Onan YD Genend Manual

900-0184 Onan YD Generators & Controls Service manual (11-1983)L 900-0184 Onan YD Generators & Controls Service manual (11-1983)L

User Manual: Onan-YD-Genend-Manual onan

Open the PDF directly: View PDF PDF.
Page Count: 111 [warning: Documents this large are best viewed by clicking the View PDF Link!]

Caution: This document contains mixed page sizes (8.5 x 11 or 11 x
17), which may affect printing. Please adjust your printer settings
according to the size of each page you wish to print.
Service
Manual
Generators
and
Controls
4.5
to
30.0
kW
USED
ON:
SK
AND DTA
SERIES
SETS
PTO
ALTERNATORS
TWO
BEARING ALTERNATORS
J-SERIES
SETS
900-0184
Reprinted
11-83
Printed
in
USA
SAFETY
PRECAUTIONS
The following symbols in this manual highlight con-
ditions potentially dangerous to service personnel, or
equipment. Read this manual carefully. Know when
these conditions can exist. Then take necessary
steps to protect personnel as well as equipment.
This symbol warns of immediate
@!@!%I
hazards which will result in severe
personal injury or death.
This symbol refers to a hazard or
@%!!@I
unsafe practice which can result in
severe personal injury or death.
This symbol refers
to
a hazard or
unsafe practice which can result in
personal injury or product or propetiy damage.
PROTECT AGAINST MOVING PARTS
Avoid moving parts of the unit. Avoid use of loose
jackets, shirts or sleeves due to danger of becoming
caught in moving parts.
Make sure all nuts and bolts are secure. Keep power
If you must make adjustments while the unit is
running, use extreme caution around hot manifolds,
'
shields and guards in position.
moving parts, etc.
Do not work on this equipment when mentally or
physically fatigued.
GUARD AGAINST ELECTRIC SHOCK
Disconnect electric power before removing protec-
tive shields or touching electrical equipment. Use
rubber insulative mats placed on dry wood platforms
over floors that are metal or concrete when around
electrical equipment.
Do
not wear damp clothing
(particularly wet shoes) or allow skin surfaces to be
damp when handling electrical equipment.
Disconnect batteries to prevent accidental engine
start. Jewelry is a good conductor of electricity and
should be removed before working on electrical
equipment.
Use extreme caution when working on electrical
components. High voltages cause injury or death.
Follow all state and local codes.
To
avoid possible
personal injury or equipment damage, a qualified
electrician or an authorized service representative
must perform installation and all service.
IAWARNING
I
EXHAUST
GAS
IS
DEADLY!
Exhaust gases contain carbon monoxide, an odorless and colorless gas. Carbon
monoxide
is
poisonous and can cause unconsciousness and death. Symptoms of
carbon monoxide poisoning can include:
Dizziness
0
Nausea Muscular Twitching
Headache Vomiting
Weakness and Sleepiness
Throbbing in Temples
Inability to Think Coherently
IF
YOU
OR ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT
INTO THE FRESH AIR IMMEDIATELY.
It
symptoms persist,
seek
medical atten-
tion. Shut down the unit and do not operate until it has been inspected and
repaired.
Protection against carbon monoxide inhalation includes proper installation and
regular, frequent visual and audible inspections of the complete exhaust system.
1-PIEM
Redistribution or publication of this document, 
by any means, is strictly prohibited.
Supplement
900-1
002
Date:
12-94
lnsett
with-
Tile:
YD
Generators
and
Controls
Service
Manual
Number:
900-0184
Date:
11-83
~~ ~ ~ ~
This supplement to the YD Service Manual adds information specific to the Onan PROTEC series of
YD PTO AC generator/voltage regulator systems.
NOTE:
The
YD
PTO
product referred to
in
the
YD
Service Manual
is
an earlier
Onan
product,
no
longer
being
manufactured.
CONTENTS
OF
SUPPLEMENT
TITLE
PAGE
GeneratorNoltage Regulator Troubleshooting
........................................
1
GeneratodRegulator Tests
........................................................
.5
12/15
KW
Generator Meter/Breaker Panel Schematic Diagram
(61
5-0426)
..............
13
16/20,20/24
KW
Generator MeterBreaker Panel Schematic Diagram
(61
5-0427)
........
14
24/30,30/35
KW
Generator MeterBreaker Panel
Schematic
Diagram
(61
5-0428)
.......
.I5
YD
PTO
AC
Generator Wiring Diagram
(61
2-6678)
..................................
.I6
GENERATOWVOLTAGE REGULATOR
TROUBLESHOOTING
This section contains troubleshooting informa-
tion for the generator and its electronic voltage
regulator. Determine the problem and then re-
fer to the appropriate
flow
chart (A,
8,
Cy D,
or
E) for troubleshooting procedures.
A.
NO
AC OUTPUT VOLTAGE AT RATED
RPM.
GINE SPEED STABLE.
B. UNSTABLE OUTPUT VOLTAGE, EN-
C. OUTPUT VOLTAGE
TOO
HIGH
OR LOW
D. EXCITER FIELD BREAKER TRIPS
E.
UNBALANCED GENERATOR OUTPUT
VOLTAGE
To
troubleshoot a problem,
start
at upper left
comer of the
chart
related to the problem,
and
answer
all
questions either YES or NO.
Follow
the chart
until
the problem is found, performing
referenced Adjustment and Test procedures
following the Flow Charts.
Referenced components
in
the Flow Charts
and
Adjustment
and
Test procedures can be
found on the schematic and wiring diagrams
found in this supplement,
and
in
the assembly
drawings found
in
the lnstallation Manual.
NOTE
Generator disassembly/assembly pro-
cedures and
PROTEC
series
YD
PTO
generator
configurations may
be
found
in
the
YD
Service
Manual
(900-0184)
and
in
the
PROTEC
Opera-
tor’s ManuaI
(929-0100)
and Installation Manual
(-).
1
FLOW
CHART
A.
NO
AC
OUTPUT VOLTAGE AT RATED ENGINE
RPM
START
Is
control panel
field
breaker CB21 on?
no
Replace defective
and
check
continuity
with
ohmmeter.
Is
breaker open?
.)
Push to
reset
breaker. Does generator
AC output voltage build up?
If
voltage
is
unstable,
high
or
low,
or
causes
breaker to trip,
see
Flow Charts
B,
C,
D
or
E.
I
Yes
-
no
Flash exciter
fidd
per
TEST
C.
Does
generator
output
voltage build
up?
3
of
VR215
to
10
VAG
or more? (TEST
A)
I
Yes
across
WE1
terminals
4
and
5
5
VDC
or
more?
I
Yes
I
no
1
Check diodes CR1 through
CR6
on
rotor
per
TEST
F.
Replace
if
bad.
Check exciter field wiring for shorts
per
TEST
L
Replace bad wiring.
Check
exciter rotor winding
per TEST
H.
Replace
if
bad.
I
I
Check exciter
fidd
wiring
Replace
bad
wiring.
Replace
fhe
regulator PC
board
per
procedure
E
if
defective. Check generator rotor winding
per
TEST
K.
Replace
if
bad.
I
1
Check
exciter field winding
1
I
Check generator stator windings
I
Der TEST
J.
ReDlace
if
bad.
-1
Conbct wifh high vol&ge can
cause
severe
personal injury or death.
Do
nof touch any exposed wir-
ing or components wiih any parf
of
the body, clothing,
tool
or
jewelry-.
Do
not use non-insulated tools inside the
control. Sbnd on an insulating mat
or
dry woodplaffom
when the control doors are open.
-1
A
newprinfedcircuit boardcan
be
dam-
aged bymalrUnctioning components within the con-
trol.
Do
not insiall the new
PC
board until all other
problems have been located and corrected.
2
FLOW
CHART
B.
UNSTABLE VOLTAGE, ENGINE SPEED STABLE
Are there
any
broken
wires
or
loose
connections
on
the
voltage regulator
assembly?
Repair
as
required.
I
Check
wiring
harness
from
regulator
assembly
to
end
bell
per
TEST
L.
Check
okav? no
-1
Repair wiring
or
replace
as
required.
I
can
be
damagedby
malfunctioning
com-
I
Yes
Replace
the
regulator
PC
board
per
procedure
E.
[-I
A
new prinfed circuit board
can
be
damagedbymaifunctioning com-
ponents within the con fro/.
Do
not ins fall
the new
PC
board until
all
other
pro&
lems
have been
located
and corrected.
Replace
the
regulator
PC
board
per
-1
Conbct with high volbge can cause severe personal injury or death.
Do
nof
touch any exposed wiring orcomponents with any parf
of
the
bod5
clothing, tool orjewel-
y.
Do
not use non-insulated
tools
inside fhe control. Sfand on an insulating mat
or
dw
wood platform when the control doors are
open.
FLOW
CHART
C.
OUTPUT VOLTAGE
TOO
HIGH
OR
LOW
START
Set
RPM
per
instructions
in
appropriate
no
I
IS
engine
ru-1
engine and/or
governor
manual.
I
Does
adjustment
of
Voltage Adjust
control
on
ihe
regulator board
result
in
I
Are
reference
transformer
T21
connections
correct
and
secure
on
yes
-1
Set
control
per
Voltage Adjustment
0.
I
Are
generator
output
leads properly
connected?
SeeTESTN.
Y=
I
the new
PC
board
unfil
all
other
prob-
lems have been locafed and corrected.
1-1
Contact with high voltage can cause severe personal injury or death.
Do
nof
touch
any
exposed wiring or components wifh anypart
of
the body, clofhing, fool orjewel-
v.
Do
nof use non-insulated fools inside fhe confml. Stand on an insulafing mat or dry
wood platform when fhe control doors are open.
3
I
FLOW
CHART
D.
FIELD
BREAKER
TRIPS
STMT
Check exciter stator winding
per
TEST
G.
Replace
if
bad. Check reference transformer
T21
per
TEST
E.
bw(
Contact with high volfage can cause severe personal injury
or
death.
Do
nof
touch any exposed wiring or components with anypart
of
the body, clothing, tool orjewel-
y.
Do
not
use non-insulated
tools
inside the control. Stand on an insulating mat or
dry
wood platfonn when the control doors are
open.
as
necessary.
FLOW
CHART
E.
UNBALANCED GENERATOR OUTPUT VOLTAGE
ponents within thecontrol,
Do
notinstall
START
Check
for
correct
grounding
of
genetator
and load.
no
output
still
unbalanced?
I
Correct
as
necessary.
Are
generator
leads connected and
I
arounded Drmerhf?
See
Procedure
N.
I
perTESTJ?
no
Replace
stator
assembly.
I
Are
genetat6
&or
winclingscontinuous
I
-1
Conbcf
with high voltage can cause severe personal injury
or
death.
Do
not
touch
any
exposed wiring
or
components with anypart
of
the bod& clothing, tool orjewel-
ry,
Do
not
use
non-insulated tools inside the confrol. Sfand on an insulating
mat
or
dry
wood
platform when the control doors
are
open.
4
GENERATOWREGULATOR TESTS
General
All
the following adjustments and tests
can
be
performed without disassembling the genera-
tor. They should be used for testing generator
regulator components in conjunction
with
the
troubleshooting
flow
charts earlier in this sup-
plement
A
-
Testing
AC
Residual
Voltage
Test for residual
AC
voltage
if
there is no AC
power output from the generator. Disconnect
propulsion engine battery cables, negative
(-)
lead first, before connecting test leads to gen-
erator leads
1
and
2.
Reconnect battery
cables, positive
(+)
cable first, start the engine,
PTO and generator and operate at normal
speed.
1-1
Accidental sfarting
of
the gen-
erator can cause severe personal injury or
death, Disconnect the propulsion engine
batterycables, negative
(-)
lead
firs&
before
connecting test leads to the controls or
generator.
Check voltage between generator leads
1
and
2
while the set is running
(see
the schematic
diagram included later in this supplement).
Use extreme caution when performing
this
test
(see warning, below). Residual voltage
should be
5
to
10
VAC.
1-1
Contact with
high
volfage can
cause sevee personal
injury
or death.
Do
not touch any exposed wiring or compo-
nents with any
part
of the
body,
clothing,
tool
or jewelv.
Do
not
use
non-insulated
fools inside the conirol. Sfand on an insu-
lating mat or
dry
wood
platform when the
control doors
are
open.
B
-
Testing Commutating
Reactor
1-1
Accidental sfarfing of the gen-
erator can
cause
severe personal injury or
death. Disconnect the
propulsion
engine
baftery
cables, negative
(-1
lead
first,
before
beginning this test.
The commutating reactor
is
shown
in
Figure
1.
It is called
CMR21
on the schematics, and
is
lo-
cated
inside the voltage regulator housing
(mounted near the generator; see Installation
and Operator's Manuals).
Only
one winding of
the reactor (leads
1
and
2)
is used on this mod-
el. Disconnect propulsion engine battery
cables, negative
(-)
lead
first
Then remove
reactor leads from the terminal board for test-
ing.
Resistance across leads
1
and
2
should be
330
to
390
milliohms at
77"
F
(25"
C). Resistance
between the winding and the reactor frame
should
be infinity.
;i
I-
I
FIGURE
1.
COMMUTATING
REACTOR
C
-
Flashing
the
Field
If
output voltage does not build up, it may be
necessary to restore residual magnetism by
flashing the field. Assemble
a
12
volt storage
battery, 10 amp
fuse,
momentary-on switch,
and diode as shown
in
Figure
2.
Disconnect propulsion engine battery cables,
negative
(-)
lead first, before connecting field
flashing leads. Connectthe positive lead tothe
FI
(+)
exciter stator lead,
and
the negative lead
to the
F2
(-)
exciter lead. Reconnect battery
cables, positive
(+)
cable
first,
then start the en-
gine,
PTO
and generator and operate
at
nor-
mal speed.
Close
the switch just long enough
for the generator output voltage to build up.
-1
lncorrecf flashing procedure
can damage the voifage reguhtor.
Do
not
keep excitation
circuitry
connecfed longer
than
5
seconds.
5
-1
Contact with
high
voltage can
cause severe personal injury
or
deafh.
Do
not
fouch
any exposed wiring
or
compo-
nenfs with any part of the body, clothh?g,
tool
or
jewelry.
Do
not use non-insulated
fools
inside the confrol. sfand on an insu-
lating maf or
dry
wood
plaffonn
when the
control doors are open.
MOMENTARYaN
SWITCH
12AMP300V
FIGURE
2.
FIELD
FLASHING
CIRCUIT
D
-
Testing Reference Transformer
Reference transformer
T21
is
located inside
the voltage regulator
housing,
mounted near
the generator.
T21
has
four
leads;
two
primary
leads marked
HI
and
H2
and
two
secondary
leads marked
Xi
and
X2.
See Figure
3.
Stop the engine and
PTO
unit.
Disconnect
leads
to
engine
starting
battery, negative
(-)
lead
first.
Disconnect transformer
T21
leads
and
make
resistance readings. The resistance
of
either coil
should
be
IO0
ohms
f
10%
at
75"
F
(25"
C).
Resistance between leads
and
transformer frame
should
be
infinity.
[BWARNINGI
Accidenial starting of the gen-
erator
can
cause severe personal injuty or
death. Disconnect the propulsion engine
battery cables, negative
(-)
lead first, before
disconnecting the reference transformer
for resisfance tesfing,
H1
>
"'
W"
FIGURE
3.
REFERENCE
TRANSFORMER
E
-
VR21
Replacement
Use
the
following
procedure
for
replacing the
voltage regulator
PC
board
or
VR
chassis.
1.
Stop
engine
and
PTO
unit.
Disconnect
leads
to
engine starting battery, negative
(-)
lead
first.
1-1
Accidenfal sfarfing of ihe
genemtor can cause severe personal
injury
or
deafh.
Disconnect the propul-
sion engine batfery cabies, negative
(-1
lead first, before conflnulng with
this
PC
board
mplacement procedure-
2.
Open the voltage regulator housing.
Dis-
connect the regulator
and
if
necessary,
la-
bel
wires. Refer
to
the
AC
control
wiring
diagram
included
later
in
this supplement.
3.
Remove
four
screws at comers
of
the
PC
board
to
remove it.
4.
Install
new
PC
board;
secure
with
four
screws.
5. Reconnect wires removed
in
step
2
at
proper terminals.
t
6
6.
Reconnect
battery
cables,
positive
(+)
cable
first.
Start
the
engine
and
PTO
and
set voltage as
outlined
in
test
(M),
Voltage
Adjustment.
F
-
Testing Rotating Rectifiers
Two
different rectifier assemblies make
up
the
rotating rectifier bridge
assembly,
Figure
4.
Us-
ing
an
accurate ohmmeter,
test
each
CR
using
negative and positive polarities. Test rectifiers
as
follows:
1.
Stop
engine
and
PTO
unit.
Disconnect
leads to
engine
starting battery, negative
(-)
lead
first.
IBWAR"G1
Accidental starting
of
the
generator can cause severe personal
injury or death. Disconnect the propul-
sion engine battery cables, negative
(-)
lead
firsf,
before continuing with this
test procedure,
2.
Disconnect
all
leads from assembly
to
be
tested.
3.
Connect
one
test lead
to
F1+
stud
and
connect other
lead
to
CRI
,
CR2,
and
CR3
in
turn;
record resistance value
of
each
rectifier.
4.
Connect
one
lead
to
F2-
stud
and connect
other
lead
to
CR4, CR5
and
CR6
in
turn;
record
resistance value
of
each rectifier.
5.
Reverse ohmmeter leads
from
steps
2
and
3
and
record
resistance
value
of
each rec-
tifier
F1+
to
CRI
,
CR2,
and
CR3
and
F2-
to
CR4, CR5,
and
CR6.
6.
All
the resistance readings
should
be
high
in
one test
and
low
in
the other
test.
If
any
reading
is
high
or
low
in
both tests, rectifier
assembly
is
defective.
Use
23
to
26
inch-lbs
(26
to
29
Nom)
torque
when
replacing
nuts
of
Fl+
and
F2-, CR1,
CR2,
CR3, CR4, CR5
and
CR6.
FIGURE
4.
TESTING ROTATING RECTIFIERS
G
-
Testing Exciter Stator
Test
the
exciter stator (Figure
5)
for
open
or
shorted
windings
and
grounds
as
follows:
Testing for Open or Shorted
WindingsStop
engine
and
PTO
unit.
Disconnect leads
to
en-
gine
starting
battery, negative
(-)
lead
first.
-1
Accidental stafiing of the gen-
erator can cause severe personal injury or
death. DIsconnect
tlte
propulsion engine
battery
cables,
negative
(-)
lead first, before
continuing with this test procedure.
Disconnect
F1+
and
F2-exciter field
leadsfrom
terminal
block
in
generator end bell. The
resis-
tance
between
field
leads
should
be
12.4
ohms
rt
10%
at
77"
F
(25"
C).
Testing for Grounds:
Stop engine
and
PTO
unit.
Disconnect leads
to
engine
starting
bat-
tery, negative
(-)
lead
first.
1-1
Accidental starling of
the
gem
erator
can
cause severe personal injury
or
death. Disconnect
fhe
propulsion engine
battery
cables,
negative
(-1
lead first,
before
continuing with this test procedure.
Connect
ohmmeter
between
either
field
lead
and
exciter
stator
laminations.
Use
ohmmeter
set
at the highest, resistance range. Resis-
tance must
be
one megohm
(1,000,000
ohms)
or
greater.
7
The
preferred test
is
with
a
megger
or
insula-
tion resistance meter that applies
500
VDC
or
more to the test
leads.
Readings
should
be
100,000
ohms or greater.
F1,
F2
LEADS
WHEATSTONE
BRIDGE OR
DIGITAL
OHMM€IER
FIGURE
5.
MEASURING
EXCITER
STATOR
RESISTANCE
H
-
Testing
Dciter
Rotor
Stop engine and
PTO
unit. Disconnect
leadsto
engine starting battery, negative
(-)
lead
first.
Accidental starfing
of
the
gen-
erator
can
cause severe personal
injury
or
death, Disconnect
the
propulsion engine
battery cables, negafive
(-)
lead first, before
continuing with these test procedure.
Test the exciter rotor (Figure
6)
for open
or
shorted windings or grounds
as
follows:
Testing for
Open
orshorted Windings:
Use
awheatstone
bridge
ordigital
VOM
forthis test.
Disconnect main rotor
field
leads
which con-
nect to rotating
rectifier
assemblies at
F1+
and
F2-. Disconnect
lead
wires from diodes
CR1,
CR2,
CR3,
CR4,
CR5
and
CR6.
Test
between
exciter
lead
pairs
TI-T2,
T2-T3,
and TI-T3.
Resistance at
770
F
(25"
C)
should
be
645
mil-
liohms
f
10%.
Testing for Grounds:
Connect
leads
of
ohm-
meter between any
CR
lead
and exciter
rotor
laminations.
Use
an
ohmmeter set at the high-
est
resistance range.
An
ohmmeter reading
less
than one megohm
(1
,OOO,OOO
ohms) indi-
cates defective ground insulation.
The
preferred test
is
with
a
megger
or
insula-
tion resistance meter that applies
500
VDC
or
more to the test
leads.
Be
sure
all
exciter
leads
are disconnected from the
diodes.
Readings
should
be
100,000
ohms
or
greater.
.
8
.
EXCITER
ROTOR
~~ ~ ~~ ~
BRIDGE OR
DIGITAL
OHMMRER
TESTING WINDING
FORGROUNDS
TESTlNG
WINDING
RESISTANCE
ES-17oOs
CONNECTION
DIAGRAM
MEGGER OR
INSULATION
RESISTANCE
METER
WHEATSTONE
~ ~
FIGURE
6.
TESTING
EXCITER
ROTOR
J
-
Testing Generator
Stator
Stop
engine
and
PTO
unit. Disconnect
leads
to
engine starting battery, negative
(-}
lead
first.
IBWAR"GI
Accidenfal sfarfing
of
the gen-
erator can
cause
severe personal injury
or
death, Dlmnneci
ihe
pmpulsion engine
baiierycables, negative
(-)
lead
firs$
before
continuing
wifh
these fest
procedure.
Using proper
test
equipment,
check
the stator
for grounds, opens, and shorts in
the
windings.
Testing
for
Grounds:
Some generators
have
ground connections tothe frame. Checkwiring
diagram.
All
stator
leads
must
be
isolated
for
testing.
Use
a
megger
or
insulation resistance meter
which
applies
500
VDC
or more
to
the test
leads.
Test
each
stator winding for
a
short
to
the
laminations.
A
reading
less
than
100,000
ohms indicates
a
questionable stator.
Thor-
oughly
dry
the stator and retest.
Testing
for
Open
or
Shorted Wlndings:
Test
for continuity between
coil
leads
shown in
Fig-
ure
7:
wire
pairs
TI
-T2
and
T3-T4
should
have
equal
resistance.
Use
an accurate instrument
for
this
test
such
as
a
Kelvin bridge or digital
ohmmeter. Resistance values at
77"
F
(25"
C)
9
are given in Table
1
(lead length between
0
and
15
feet).
TABLE
1.
STATOR RESISTANCE
VALUES
IN
OHMS,
f
10%
If
any windings are shorted, open or grounded,
replace
the
stator
assembly. Before replacing
or
insulation.
the
assembly, check the leads for broken wires
kW
RATING
RESISTANCE
12/15
.115-
.I47
1
6/20
.069
-
-091
20124
-0%
-
.072
24/30
-033
-
.043
30135
-029
-
.038
I
n
RESISTANCE
MRER
..
ESl79SS
....
t.1..
w
I
WHEATSTONE
BRIDGE
FIGURE
7.
TESTING STATOR WINDINGS
10
K
-
Testing
Generator
Rotor
I
30135
~
TABLE
2.
ROTOR
RESISTANCE
VALUES
IN
OHMS,
k
10%
2.91
Stop
engine and
PTO
unit. Disconnect
leads
to
engine starting battery, negative
(-)
lead
first.
LaWAR"i;l
Accidental starting of the gen-
erator can cause severe personal injury or
death.
Disconnect
&e
pmpulsion engine
bafterycables, negative
(-)
lead
firsf,
before
continuing
with
these
test
procedure,
For these tests, use a megger
or
insulation re-
sistance meter which applies500
VDC
or
more
to the test leads.
Testing for Grounds:
Check for grounds be-
tween each rotor lead and the rotor shaft, Fig-
ure
8.
Perfom
tests
as
follows:
1.
Remove rotor leads
F1+
and F2- from the
rotating rectifier assemblies.
2.
Connect test leads between F1+ and rotor
shaft. Meter should register
100,000
ohms or greater.
3.
If
less than
100,OOO
ohms, rotor is ques-
tionable. Thoroughly dry the rotor and re-
test.
4.
Replace a grounded rotorwith
a
new iden-
tical
part.
Testing for Opn or Shorted Windings:
Per-
form tests
as
follows:
1.
Remove rotor leads
F1-t
and F2-
from
ro-
tating rectifier assemblies.
2.
Using ohmmeter, check resistance be-
tween
Fl
and F2 leads, Figure
9.
The resistance values at
77"
F
(25"
C)
should
be
as
shown
in
Table 2. If not,
replace
defective
rotor with new, identical part.
kW
RATING
RESISTANCE
(ohms)
1
6/20
20124
I
24130
I
2.24
I
MEGGER
OR
~ INSULATION
RESISTANCE
MElER
~
CA-lOlO-12S
TESTING WINDING
.
FOR
GROUNDS
FIGURE
8.
TESTING
ROTOR FOR GROUNDS
(7-7
DIGITAL
r
-1
I
TESTING
WINDING
RESISTANCE
CA1QIO.S
FIGURE
9.
TESTING
ROTOR FOR
AN
OPEN
CIRCUIT
L
-
Wiring
Harness
Check
Stop engine and
Pi0
unit. Disconnect leads to
engine starting battery, negative
(-)
lead
first.
-1
Accidental
starting
of
fhe gen-
erator can
cause
severe personal injury
or
death. Disconnect the propulsion engine
bafieryc&les, negative
(-1
lead first, before
continuing with these
iesi
procedure.
Carefully check wiring harnesses as follows:
1.
Inspect
all
wires for breaks, loose connec-
tions, and reversed connections. Refer to
the wiring diagrams at the end
of
this sup-
plement.
2.
Remove wires from terminals at each
end
and using an ohmmeter, check each wire
end to end for continuity or opens.
3.
Using an ohmmeter, check each wire
against each
of
the other wires and to
ground
for
possible shorts
or
insulation
breaks under areas covered by wrapping
material.
4.
Reconnect or replace wires
according
to
the wiring diagrams at the end
of
this
sup-
plement.
M
-
Voltage
Adjustment
When checking output voltage, be sure that the
generator has stabilized and is running
at
the
correct speed (frequency).
Accidental starting
of
ihe gen-
erafor can
cause
severe personal injury or
death, Dlsconnecf
fhe
propulsion engine
baffery
cables,
negative
(-)
lead
first,
before
connecting test leads
to
the controls
or
generator.
.
-1
Contacf
wifh
high
voltage can
cause severe personal injury
or
death.
Do
not touch any exposed wiring
or
compo-
nenfs with any
part
of
the
bod%
clothing,
tool
or
jewelry.
Do
nof
use
non-insulated
tools
inside the control. Sfand on
an
insu-
laiing mat or
dry
wood
plaffonn when the
control doors are open.
With the generator running, set the voltage
ad-
just
potentiometer
on
the
regulator board as-
sembly
for
correct voltage. See Figure
10.
I
I
0
0
VOLTAGE
ADJUST
I
FIGURE
10.
VOLTAGE REGULATOR BOARD
INSIDE
CONTROL
BOX
N
-
Reconnection
Generator reconnection conforms to
AC
wiring
diagram
612-6678,
supplied
in
this supple-
ment.
Also
see the Installation Manual
for
out-
put connection
and
generator reconnection
guidelines.
12
.
T
I
I
I
I
I
STUD
ON
BOTTOM
OF
BOX
(UNGROUNDED)
I
I1
I
I
TO
LOAD
I,
LO
1
L2
I
TO
I
I
GENERATOR
T2,
T3
TI-
-
@-@
I
z
M3
I
M4
T4-
I
L
I
I
I
METER-FREQUENCY
METER-AC
VOLT
12/15
KW
GENERATOR METEWBREAKER PANEL SCHEMATIC
DIAGRAM
13
NO.
615-0426
REV.
A
MODIFIED
INSIDE VIEW
OF CONTROL
BOX
TO
GENERATOR
-
-
__
-
-
-
- -
-
- -
-
- - -
-
__I
T
TERMINAL BLOCK
CIRCUIT BREAKER
TRANSFORMER-CURRENT
METER-FREOUENCY
METER-TIME TOTALIZING
METER-AC VOLTAGE
!
IA
TB
1
CB
I
CT1
,
CT2
M5
M4
M3
I
I
I
I
I
I
I
-
I
I
I
I
I
I
I
I
I
I
I
I
LU
CT2
m
I
13
I
It!
(‘I
TT
M4
7
II
I
t
-1
REAR VIEW
I
7
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
-
-
7
6
5
4
3
2
L1
I
\METER-AC
AMMETER
/MI
.2
RF
ITEM^
DESCWPTION
OR
MATERAL
DES
16/20,20/24
KW
GENERATOR
METENBREAKER
PANEL
SCHEMATIC
DIAGRAM
NO.
615-0427
REV.
A
MODIFIED
.
14
TABLE
OF
CONTENTS
.
.'
TITLE
PAGE
Safety Precautions
..................................................
.Inside Cover
Introduction
...................................................................
2
GENERATOR TROUBLESHOOTING
............................................
5
Part
1
4.5 to
25
kW
Range
................................................
5
Part
II
25
to
30
kW Range
.................................................
21
Generator Repair. J-Series
.................................................
35
Disassembly
..........................................................
35
Assembly
..................................
............................
36
PTO ALTERNATORS
..........................................................
37
Specifications
.............................................................
38
Wiring Connections,
15-25
kW
.............................................
40
..
Troubleshooting
...........................................................
41
Service and Maintenance
...................................................
42
TWO
BEARING ALTERNATORS
................................................
43
Troubleshooting
....................................
i
.....................
46
..
.
Specifications
....................................
:
........................
45
Alternator Repair
..........................................................
47
Gear Case Disassembly
................................................
47
Alternator Disassembly
................................................
49
Alternator Assembly
...................................................
54
CONTROL
SYSTEMS
.........................................................
55
Engine Control System Operation
..........................................
58
Gasoline Powered
Sets
................................................
58
Diesel Powered
Sets
...................................................
58
Radiator Cooled
Sets
..................................................
62
Engine Control Troubleshooting
............................................
67
Control Component Checkout
.............................................
70
WIRING DIAGRAMS
..........................
;
...............................
72
TO AVOID POSSISLE PERSONAL INJURY OR
EQUIPMENT DAMAGE. A QUALIFIED ELECTRI-
CIAN
OR
AN AUTHORIZED SERVICE
.
REPRESENTATIVE MUST PERFORM IN-
STALLATION
AND
ALL SERVICE
.
.
1
I
NTROD
UCTl
ON
JB
JC
''
MJC
RJC
JC
I
MJC
RJC
SK
GENERAL
This
manual contains troubleshooting and repair
procedures for the
YD
generators and controls..
Engine information
is
in
the applicable engine man-
ual. Three
systems
which could cause the electric
generating set to malfunction are the generator, the
control and the engine.
The
YD
generator information includes description,
troubleshooting, adjustments and tests for repairing
the generator, exciter and voltage regulator.
The majorsection of
this
manual applies to most,
but
not
all,
YD
generators.
In
the development of larger
capacity generators
in
the
YD
family,
Onan
has
included some modifications
so
that the generator
would have adequate motor-starting capability.
These modificationsinvolve two basic areas:
1.
The rotating exciter (rotor and stator)
is
about
112
inch thicker than standard.
This
results
in
the
winding
resistances being different from the
majority of generators.
2.
The
"UR"
regulation system
is
used rather than
the standard
YD
regulator.
The generator set models affected
by
the above mod-
ifications include:
25
kW
MDTNDTA'generator sets
30
kW
SK
generator sets
30
kW
YD
PTO
generators
.
'
Separate sections of
this
manual should be referred
to for information on these models which
is
different
from that provided
in
the main body of the manual.
The Controlsystem informatipn includes description
and troubleshooting procedures for repairing the set
if
the trouble
is
in
starting, stopping, or
if
thesetshuts
down because of an emergency condition.
MANUAL
REFERENCE
FOR
YD
GENERATOR
SETS
AND
ALTERNATORS
Diesel
DJB
DJE
MDJE
DJC
MDJC
RDJC
MDJF
RDJF
MDTA
DTA
YD
PTO
Alternator
YD
Two Bearing
k
60
Hz
7.5
12.5
10.0
12.5
15.0
15.0
15.0
30.0
6.0
6.0
7.5
12.0
120
15.0
15.0
17.5
25.0
25.0
15.0-30.0
5.0-20.0
I
50
Hz
6.0
10.0
12.5
.
125
25.0
:
4.5
x
4.5
6.0
9.0
10.0
12.5
12.0
14.5
15.0-30.0
5.0-16.0
STATOR
STACK
LENGTH
2.88
4.31
3.44
4.31
5.00
,
5.00
4.31
'7.00-10.38
..
2.19,
2.19
'
2.88
4.31
4.31
5.00
5.00
5.75
8.62
8.62
5.00-8.62
2.1 97-00
2
PARTS CATALOG
967-0223
967-0220
968-0340
974-0220
967-0220
968-0340
974-0220
946-0220
967-0221
967-0225
968-0224
967-0222
968-0222
974-0221
974-0222
961-0222
961 -0220
929-0002
929-0004
968-om
OPERATOR'S MANUAL
967-01 23
'*
967-01
20
968-0340
974-01
20
-. .
967-01 20
968-0340
974-01
20
946-01
20
967-01 21
967-01
25
.
968-0120
967-0122
968-01 22
974-0121
968-0121
974-0122
961-0122
961-0120
929-0002
929-0004
I
.a.
Typical
wiring diagrams
are
Included
at
the end
of
this manual to
help personnel trace
or
isolate problems. Onan suggests, however,
that service personnel
use
the wiring diagrams shipped with the
units.
Repair information
is
not extensive because the
solid-state printed circuit boards lend themselves
more to replacement
that
repair.
ONAN
does
not
recommend repair
of
the printed circuit boards,
except at the factory and has initiated a return/
exchange service obtainable through distributors,
whereby faulty printed circuit boards can be returned
and exchanged for good
units.
For
more information,
contact your Onan distributor.
Application
of
meters or high heat soldering irons to
printed circuit boards
by
other than qualified person-
nel can result
in
unnecessaryand expensive damage.
High voltage testing
or
high potential
(or
Megger) testing
of
generator windings can
cause damage to solid state components. Isolate these compo-
nents
before
testing.
TEST EQUIPMENT
Most of the test procedures
in
this manual can be
performed with
an
AC-DC
multimeter such
as
a
Simpson Model
260
VOM.
Some other instruments to
have available
are:
ENG
IN€
AD
CENEf
IAPTER
Onan
Multitester
Wheatstone
Bridge
Kelvin
Bridge
Jumper Leads
Onan Load Test Panel
Variac
AC
Voltmeter
DC
Voltmeter
See Tool Catalog
900-0019.
GENERATOR DESCRIPTION
The
YD
generators
(Figure
1)
are four-pole, revoiving
field,
brushless
exciter, reconnectible models of
drip-
proof construction. Design includes both single and
three-phase,
60
and
50
hertz type generators. The
generator rotor connects directly to the engine
crankshaft
with
a tapered shaft and key. It
is
fastened
by
the
rotor-through-stud
which
passes through the
rotor shaft and a nut on the outside
of
the end
bell.
A
centrifugal blower, on the front
end
of the rotor shaft,
circulates the generator cooling air which
is
drawn
in
through the end
bell
cover
and
discharged through
an
outlet at the blower end.
A
ball bearing
in
theend
bell
supports theouterend of
the rotor shaft. The end
bell
and generator stator
housing are attached
by
four-through-studs which
pass through
the
stator assembly to the engine-
THROUGH-STUD
FIGURE
1.
TYPICAL
YD
J-SERIES GENERATOR (SECTIONAL VIEW)
3
generator adapter. The brushless exciter stator
mounts in the end bell while the exciter rotor and its
rotating rectifier assemblies mount on the generator
rotor shaft.
All
generators have four wires extending from the
stator housing in addition to the
AC
output leads,
Figure
2.
Lead
B2
is from the battery charge winding
and connects to terminal
7
of the engine control.
Lead F1+ and
F2-
are from the exciter field winding
and are connected to the output terminals of the
voltage regulator. Leads
1
and Pare connected to the
stator windings and provide reference voltage and
input powerto thevoltage regulator. These four leads
are connected at the factory.
Figure 2
is
a composite illustration showing four
output
leads
for
single-phase units, l2output leadsfor *phase broad
range
units,
and four output leadsforcode 9x3-phase
347l600volt
generators.
TO
CHARGING
BAlTERY
RESISTOR
CHARGING
Generator sets without a control panel or
switchboard containing
AC
instruments such as
voltmeters, ammeters, running time meter, frequency
meters, and line circuit breakers are shipped from the
factory with the
AC
output leads separated in the
output box. On generator sets with switchboards
containing
AC
instruments, the
AC
output leads are
wired as specified on the customer's purchase order
to deliver only the voltage specified.
-
VOLTAGE RECONNECTION WITH
OPTIONAL INSTRUMENTS
The optional
AC
instruments on the control panel
(such as voltmeters, ammeters, transformers, and
running time meters) are intended for use with
specific nameplate voltages. Control components
may have to be changed to match new current ratings
when field reconnection for other voltage codes
or
voltages are made.
To prevent instrument damage contact the
a
Onan factory for required instrument
changes, new wiring diagrams, new plant nameplate with proper
specification number and voltagebefore attempting to reconnect a
generator with instruments on the control panel.
Under no circumstances shall the generator
be
connected in any
other mannerthan shown in the applicable wiring and reconnec-
tion diagrams.
CAUT,ON
CHARGING
RESISTOR
ENGINE
-CONTROL
F2-n
r77
TO
VOLTAGE
1
REGULATOR
Severe damage
will
result if leads are incorrectly connected or
improperly insulated.
Use
extreme care in checking leads to assure
proper connections.
.
FIGURE
2
SINGLE AND THREE
PHASE
GENERATOR
SCHEMATIC (COMPOSITE)
GENERATOR OPERATION
Operation of the generator involves the stator, vol-
tage regulator, exciter field and armature, a full wave
bridge rectifier, and the generator rotor, Figure
3.
Residual magnetism in the generator rotor and
a
permanent magnet embedded in one exciter field
pole begin thevoltage build-up processasthe gener-
ator set starts. Single-phase
AC
voltage, taken from
one of the stator windings, is fed to the voltage regu-
lator as a reference for maintaining the generator
output voltage.
AC
voltage
is
converted to
DC
by
a
silicon controlled rectifier bridge on
the
voltage regu-
lator printed circuit board and fed into the exciter
field windings. The exciter armature produces three-
phase AC voltage that is converted to
DC
by
the
rotating rectifier assembly. The resultant
DC
voltage
excites the generator rotor winding to produce the
stator output voltage for the
AC
load.
The generator rotor also produces
AC
voltage
in
the
'
charging winding of the stator which is converted to
direct current for battery charging.
h
FULL WAVE
BRIDGE
RECTI
FIE
R
RESIDUAL
.
MAGNETISM
IN
ROTOR
STARTS
ROTOh
I
B
RUSHLESS
REFERENCE
VOLTAGE EXCITER
FIELD
I
FIGURE
3.
EXCITATION BLOCK DIAGRAM
4
GENERATOR
TROUBLESHOQTING
"
PREPARATION
A
few simple checks and a proper troubleshooting
procedure can locate the probable source of trouble
and cut down service time.
Check all modifications, repairs, replacements
performed since last satisfactory operation
of
set
to ensure that connection of generator leads are
correct. A loose wire connection, overlooked
when installing a replacement part could cause
problems. An incorrect connection, an opened
circuit breaker, or a loose connection on printed
circuit board are all potential malfunction areas
to be eliminated by a visual check.
Unless absolutelysure that panel instrumentsare
accurate, use portable test meters for trouble-
shooting.
Visually inspect components on VR21. Look for
dirt, dust, or moisture and cracks in the printed
solder conductors. Burned resistors, arcing
tracks are all identifiable.
Do
not mark
on
printed
circuit boards with a pencil. Graphite lines are
conductive and can cause leakage or short cir-
cuits between components.
The PART
I
TROUBLESHOOTING PROCEDURES
are
for
YD
generators
in
the
4.5
to
25
kW size range
using the standard
YD
regulator and generator.
The PART
I1
TROUBLESHOOTING PROCEDURES
(page
21)
are for
YD
generators
in
the
25
to
30
kW size
range. These units have thicker exciters and use the
UR type regulation system.
PART
I
TROUBLESHOOTING
PROCEDURES
(STANDARD
YD
GENERATOR AND
REGULATOR)
The information in this section is divided into Flow
Charts A,
6,
C,
D,
and E as follows:
A.
NO
AC OUTPUT VOLTAGE AT RATED ENGINE
B. UNSTABLE OUTPUT VOLTAGE, ENGINE
C.
OUTPUT VOLTAGE TOO HIGH OR LOW.
D.
EXCITER FIELD BREAKER TRIPS.
RPM.
SPEED STABLE
1800
RPM.
E. UNBALANCED GENERATOR OUTPUT VOLT-
AGE.
To troubleshoot a problem, start at upper-left corner
of
the chart related to problem, and answer all ques-
tions either
YES
or NO. Follow the chart until the
problem is found, performing referenced Adjustment
and Test procedures following the Flow Charts.
Referenced components in the Flow Charts and
Adjustment and Test procedures can be found on the
electrical schematic Figure
4,
and on assembly draw-
ings and wiring diagrams on pages 18-20.
DC
VOLT.
REG.
PC
BOARD
OUTPUT
VOLTAGE
VR21
EXCITER
ROTOR
RECTI
Fl
ER
(M,
ME)
ASSEMBLIES
REGULATOR
ASSEMBLY
FIGURE
4.
ELECTRICAL SCHEMATIC, STANDARD YD GENERATOR AND REGULATOR
5
FLOW
CHART
A.
NO
BUILD UP
OF
AC
OUTPUT VOLTAGE
Replace defective
field breaker.
Remove one lead from breaker
and check continuity with
ohmmeter.
Is
breaker open?
Is
control panel field
breaker CB21
ON?
If
voltage is unstable, high or low, or
causes breaker to trip, see Flow Charts
B, C, or D.
Push to reset breaker. Does generator
AC output voltage build up?
Flash exciter field per TEST [E]. Does
generator output voltage build up?
no
Is reference voltage across TB21-1
&
2
20 VAC or more? -no
I
Disconnect stator leads
1
&
2 from TB21-
1
&
2.
Is
reference voltage across leads
20 VAC or more now?
Check commutating reactor CMR21 per
TEST
[I].
Replace if bad.
I
1
Check reference transformer T21 per
TEST
[J].
Replace if bad.
I
I
Check diodes CR1 through CR6
on
rotor
per TEST [F]. Replace if bad.
I
Is
exciter field voltage Check wiring harness
W9
for
across TB21-3
&
4
7.0VDC
shorts
per TEST
[O].
Replace
bad wiring.
Check wiring harness
W9
for
opens per TEST [O]. Replace
bad wiring.
d
Check exciter field winding
per TEST
[K].
Replace if
bad.
I
Check SCRs CR13
&
CR16per
TEST
[HI.
Replace if bad.
I
I
Check exciter rotor winding
per
TEST
[L].
Replace if bad.
Check generator rotor field
winding per TEST
[MI.
Replace
I
if bad.
,
I
Check
generator stator wind-
ings per TEST
[N].
Replace
Check diodes CR12,14
&
15 per
TEST
[GI.
Replace if bad.
I
1
I
Replace voltage regulator PC
board per procedure IP].
I
Do
not
replace
the printed
cir-
cuit
boarduntil thetroublenot
on the
PC
board
has been located and corrected
to
avold damage
to
new
PC
board.
6
FLOW
CHART
B.
AC
OUTPUT
VOLTAGE
BUILDS
UP,
BUT
IS
UNSTABLE
Are there any broken wires or loose
connections on voltage regulator
assembly
VRZ?
-Yes
+
Repair
as
required.
I
no
-
I
1
1
I
I
Is
engine running at correct
RPM?
t
Check wiring harness from
VR22
to end bell
per TEST
[O].
Check
OK?
I
Set
RPM
per instructions
in
appropriate
engine manual.
-no-+
Repair wiring or replace
as
required.
Is
jumper wire
W10
connected correctly on VR21
and correct if needed.
i
for desired voltage? See Figure
19
on page 20
L
1
I
I
I
*
Are generator output leads properly connected?
See
Figure
19
and correct if needed.
I
Does
adjustment of Dampening Control
R27 on VR21 per adjustment
[B]
result
Is
voltage stable within spec at no
load to
full
load range
of
generator
set?
I
no no
Replace voltage regulator
PC
board per
procedure
[PI.
Do
not replace the printed circuit board
until the trouble not on the
PC
board has
__~__~_~_
been located and corrected to avoid damage to new
PC
board.
FLOW CHART
C.
AC OUTPUT VOLTAGE BUILDS
UP,
BUT
IS
HIGH OR LOW
START
Does adjustment
of
Voltage Adjust control
R22
on VR22 result
in
correct output
voltage?
Set control per Voltage Calibration
Adjustment [A].
Do
not replace the printed circult board
until the trouble not on the
PC
board has
been located and corrected to avoid damage to new
PC
board.
I
Replace voltage regulator
PC
board
VR21
per
procedure
[PI.
F
I
I
7
FLOW
CHART D. AC OUTPUT VOLTAGE BUILDS
UP,
BUT
FIELD
BREAKER TRIPS
Checkgenerator rotor field winding per
*
TEST
[MI.
Replace
if
bad.
Does AC output voltage build up to
140%
or
more of rated voltage before breaker trips? Check for any loose or broken wires or connections
on VR22 assembly.
no
Check generator stator windings per TEST
[N].
Replace if bad.
Check exciter rotor winding per TEST
[L].
Replace if
bad.
I
f
I
Check generator stator leads for proper
connection.
See
Figure
19,
page
20.
I
I
DO
nOt replam the printed
CiEUit
board
until
the
trouble not on the
PC
board has
been
located and
corrected
to
avoid damage to new
PC
board.
Replace voltage regulator PC board VR21
per procedure
[PI.
8
.*
FLOW
CHART
E.
UNBALANCED GENERATOR OUTPUT VOLTAGE
---no+
Are generator leads connected and grounded
properly?
See
Figure
19,
page
20.
Correct
as
necessary.
1
r-
Is
generator
stator
winding
continuous
per
TEST
[K]?
Check
load
for ground faults
and
correct
as
necessary.
-no- Replace
stator
assembly.
9
ADJUSTMENTS
AND
TESTS
(STANDARD YD GENERATOR AND REGULATOR)
GENERAL
All of the following Adjustments and Tests can be
performed, without disassembly of the generator.
They should be used for testing generator and regu-
lator components
in
conjunction with the trouble-
shooting flow charts.
..
VOLTAGE CALIBRATION ADJUSTMENT
Thecalibration adjustmentis made using an accurate
AC voltmeter to observe generator output voltage
and to set the correct no load voltage. If voltage regu-
lator VR21 printed circuit board has been replaced,
it
may be necessary to make a calibration adjustment.
To
obtain the correct output voltage, proceed as
follows:
1.
If set hasavoltageadjust potentiometer (R22) on
the meter panel, set pointer halfway between min-
imum and maximum positions.
2. With unit running at no load, turn generator
vol-
tage potentiometer R26on VR21 (Figure
5)
clock-
wise to increase output voltage; turn R26 coun-
terclockwise to decrease output voltage.
VOLTAGE STABILITY ADJUSTMENT
Voltage stability is set at the factory, but if printed
circuit board VR21 has been replaced or if damping
potentiometer R27 has been unnecessarily adjusted
it
may be necessary to reset stability. Set stability as
follows:
1.
With generatorset running at no load, turn poten-
tiometer R27 (Figure
5)
to a position where vol-
tage tends to be unstable or hunt.
2. Turn R27 clockwise slowly until voltage first sta-
bilizes. This setting will result
in
stable voltage
under all conditions in maximum voltage regula-
tor response time.
BATTERY CHARGE RATE ADJUSTMENT
One generator winding supplies current for the bat-
tery charging circuit. The current flows through
diode CRl1, ammeter M11, to the battery, and to the
ignition-fuel solenoid circuits.
1.
The slide tap on adjustable resistor R21, located
in the generator air outlet, should be set to give
about 2 amperes charging rate, Figure 2. For
applications requiring frequent starts, check bat-
tery charge condition (specific gravity) periodi-
cally and if necessary, increase charging rate
slightly (slide tap nearer ungrounded lead) until
it
keeps battery charged: Having engine stopped
when readjusting avoids accidental shorts. Avoid
overcharging.
.
a.
19 volts on 12 volt battery charge models,
b. 38 volts on 24 volt battery charge models,
c.
50
volts on 32 volt battery charge models,
test the charging circuit for opens or grounds in
the leads and charging winding.
If
leads are
defective, replace them. If winding
is
defective,.
replace generator stator.
3. If a separate automatic demand control for start-
ing and stopping is used, adjust charge rate for
maximum
4.5
amperes. This normally keeps bat-
tery charged even if starts occur as often as
15
minutes apart.
2.
If charge winding AC output is below: .
VOLTAGE REGULATOR CHECKOUT
The solid state voltage regulators (VR21) can be
checked out on the bench for proper operation or
location of faulty components. The following test
equipment (one-each)
is
required fora proper check-
out.
REF. DESIGNATION TEST EQUIPMENT
S
........................................
Switch
CMR21
..................................
Reactor
F..
.................................
Fuse,
5
Amps
T1
...........
Transformer, Variable 2 Amp 0-15OV
V2
............
Voltmeter,
.DC
f
2% of Full Scale 3,
Scale
Q.50
and 0-15OV and 0-1OV
V1
.....
Voltmeter, AC
f
2%
@
lOVAC,
1%
@
150V
R1
.....................
.Resistor, 100-Ohm
400
W
T21
.................
.Transformer, Input 315-0386
...
Transformer T21 and reactor CMR21 are a part of the
voltage regulatorassembly (VR22orVR23); theseare
the only parts obtainable with an Onan part number.
The big 100-ohm
400
watt resistor (Rl) serves as the
field during checkout.
I
10
Bench
Check
3.
Open switch
in
120
VAC
supply to
VARIAC.
4.
Piug
VARIAC
into
120
VAC
source.
5. Proceed with checkout according to steps
in
1.
Remove
voltage
regulator from
unit
according to
procedure given for voltage regulator replace-
ment. Table
1.
2.
Referring to Figure
5
and Table
1,
connect test
equipment to the printed circuit board
VR21
ter-
minals as follows:
[El
CONNECT
FROM
TO
.
FLASHING THE
FIELD
Jumper
Jumper
Lead
Lead
Lead
Lead
AC Voltmeter
DC
Voltmeter
VARIAC
R1
VR21-V1 VR21
-V4 The following procedure is used for momentarily
VR21-1 vR21-2
flashing the exciter field with
a
low voltage which
CMR21-1 vR21-10
restores the. residual magnetism
in
the alternator
CMR21-4 vR21-9
rotor. Flashing the field is usually necessary when
installing a new brushless exciter stator wound
T21-X1 VR21-6
assembly, but seldom is necessary under other
T21
-X2
vR21-4
Across T21-H1 &
H2
Across
VR21-7
8
8
. circumstances. Always check generator residual
Across T21-H1
(fused)
voltage at terminals
1
and
2
to be certain whether or
not flashing the field is necessary. Generator residual
and
H2
Across.
VR21-7
h
8
TABLE
1.
VOLTAGE REGULATOR CHECKOUT
.
I1
Ac
1m
VOLT=
(<=LESS
THAN)
"2
Dc
toLIIsE
(>=
MORE
THAN)
OCCURS
INCREASE
W7
TO
STABIL-
r----------
I
WIOJUMPER
VOLT
,I
'1
WioJuwER
I
I
I
I
I
I
L---------d
El
Ck
AC
INPUT
VOLTMETER
DAMPING
a0
70
v
VR21
I
FIGURE
5.
VOLTAGE
REGULATOR
CHECKOUT
EST EQUIPMENT CONNECTIONS
11
6
VOLT
DRY
CELL
BATTERY
'
.
FIGURE
6.
MSHlNGTHEFiELD
voltage should be at least
20
VAC
at rated speed. If
residual is too
low
and the output voltage will not-
build up, flash the field as follows:
Locate terminals
7(-)
and
8(+)
on
..
voltage
-
regulator printed circuit board (VR21).
Use a six volt dry cell battery with
two
clip leads
anda12amp,300voltdiodeasshown
in Figure6.
If a six volt battery is not available, a
12
volt auto-
motive battery
can
be
used
by
adding a 20-ohm
resistor
in
series; or a
24
volt automotive battery
can be used by increasing the resistance
to
40-oh ms.
After starting engine, touch positive
(+)
battery
lead to the+8, and negative
(-)
lead to
-7
terminals
.
just long enough until voltage starts to build up or
damage may occur to exciter-regulator system.
Be
cautious
when
worklng on
a
generator
1-1
that
is
running
to
avoid
electrical
shacks.
TEST PROCEDURES
All
of the following tests can be petformed without
disassembly
of
the generator. Use the following test
procedures for testing generator components in con-
junction with the troubleshooting charts.
TESTING ROTATING RECTIFIERS
Two
different rectifier.gssemblies make up
the
rotat-
ing rectifier bridge assembly, Figure
7.
Using an
accurate ohmmeter, test each CR using negative and
positive polarities. Test rectifiers
as
follows:
1.
Disconnect all leads fromassembly to be tested.
2.
3.
4.
5.
6.
-.
Connect one test lead to F1+ stud and connect
other lead toCR1, CR2, and CR3
in
turn; record
resistance value of each rectifier.
Connect one lead to F2- stud and connect other
lead
to
CR3, CR4 and CR5 in turn; record resist-
ance value of each rectifier.
Reverse ohmmeter leads from step
2
and record
resistance value of each rectifier F1+ to CR1,
CR2, and
CR3
and
F2-
to
CR4,
CR5, and
CR6.
All three resistance readings should be high in
one test and low
in
the other test. If any reading is
high
or
low
in
both tests, rectifier assembly is
defective.
Replace defective rectifier assembly with new,
identical part.
Use
24
Ibs-In.
(27
Nw)
toque when tightening nuts on
F1+
and
F2-, CR1,
CR2,
CR3, CR4, CRS,
and
CR6.
FIGURE
7.
TESTING ROTATING RECTIFIERS
12
5
CR13
CR12
R17
F1+
F2-
EXCITER
FIELD
i
I I
I
CR15
I
8
FIGURE
8.
SILICON CONTROLLED
RECTIFIER BRIDGE
[GI
TESTING OUTPUT BRIDGE DIODES
The output bridge rectifier diodes (Figure
8),
CR12,
CR14,
and CR15, are located on the voltage regulator
printed circuit board. Using an accurate ohmmeter,
test diodes CR12, CR14, and CR15 as follows:
1.
Connect one ohmmeter lead to each end of diode
2.
Reverse ohmmeter leads and again observe re-
and observe resistance reading, Figure
9.
sistance readings.
A
good
diode has a higher reading In one direction than the
other.
If
both
readings are high,
or
low,
diode
is
defective.
3. Replace defective diodes with new, identical
parts.
TESTING
SCR'S
Two identical silicon controlled rectifiers
(SCR's),
CR13and CR16, control the DC output voltage to the
exciter field. These
SCR's
are mounted
in
heat sinks
on
the
voltage regulator and are tested as follows:
1.
Using high scale on ohmmeter, connect ohmme-
ter leads to anode and cathode of the SCR as
shown in Figure 10. The resistance reading
should be one megohm or greater. Reverse ohm-
meter leads to anode and cathode; resistance
should again be one megohm or greater.
FIGURE
9.
TESTING DIODES
2. Using a &volt dry cell battery and a 200-ohm
series resistor, observe correct polarity and con-
nect battery leads to anode and cathode as
shown in Figure
11.
Observe polarityand connect
a
DC voltmeter across the
200
ohm resistor. The
voltmeter should now read zero. Jumper anode to
gate: voltmeter should now read &volts. Remove
jumper; voltmeter should still read &volts be-
cause the SCR remains turned on until voltage is
removed from anode to cathode.
3.
If the SCR does not pass eithertest, it is defective.
Replace defective SCR with a new, identical part.
OHMMETER
FIGURE
10.
SCR RESISTANCE
TEST
13
X1,
and
X2. H1-H2
are the primary leads.
Xl-X2
are
the secondary leads.
MULTIMETER
LLkJ
1
TO
1
RATIO
T21
XI
x2
Resistance between
H1-H2
should be
113
to
139
ohms, between
Xl-X2 133
to
163
ohms at
77OF
(25OC).
Resistance between coils and from
any
ter-
minal to transformer frame should be infinity.
/KI
TESTING
BRUSHLESS
EXCITER STATOR
Like the generator, the brushless exciter stator
(Fig-
ure
12)
can
be
tested for open or shorted
windings
and grounds.
Testing
for
Open
or
Shorted Windings:
Disconnect
Fl+
and
F2-
exciter
field
leads
from
ter-
FIGURE
11.
SCR
VOLTAGE
TEST
111
TESTING REACTOR
The reactor assembly
CMR21
leads are marked
1,2,3
and
4.
Wires
1-2
and
3-4
are wound on the same iron
core.
1
2'
CMRPI
rn
3.
4
Resistance between
1-2
and
3-4
should be
0.33
to
0.39
ohms
and
0.38
to
0.46
ohms respectively at 77"
F
(25°C).
Resistance between coils (e.g.
1-3)
and from
any terminal to reactor frame should be infinity.
[Jl
TESTING REFERENCE TRANSFORMER
The transformer
T21
has four leads marked
H1,
H2,
minal block
in
generator
end
bell. The resistance
between
field
leads should be
10.98
to
13.42
ohms at
68"
F
(20'
C).
Testing
for
Grounds:
Connect ohmmeter between either
field
lead and
exciter stator laminations. Use ohmmeter set at
RX
100
scale.
An
ohmmeter reading
of
less
than infinity
(
oc
)
indicates defective ground insulation.
OHMMETER
RESISTANCE
BETWEEN
F1
AND
F2
SHOULD
BE
10.98
TO
13.42
OHMS
FIGURE
12
TESTING EXCITER FIELD
[LI
TESTING
BRUSHLESS
EXCITER
ROTOR (ARMATURE)
The brushless exciter rotor (Figure
13),
can be tested
for open or shorted windings, or grounds.
.
14
OHWETER,
c
FI
I
CONTACT
ONE
PROD
TO
EACH
OF
mE
FLELD
LEADS AND OTHER
PROD
TO ROTOR SHAFT.
IF
ROTOR
IS
GOOD, THERE
WILL
BE
NO
0215
READING
ON
OHWlETER.
FIGURE
14.
TESTING ROTOR FOR GROUNDS
FIGURE
13.
TESTING
EXCITER ARMATURE
Testing
for
Open
or
Shorted Windings:
Use a Wheatstone Bridge for this test. Disconnect
main rotor field leads which connect to rotating recti-
fierassemblies at Flcand F2-. Disconnect lead wires
from diodesCR1, CR2, CR3, CR4, CR5and CR6. Test
between exciter lead pairs T1-T2, T2-T3 and Tl-T3.
.
Resistance should be
0.5
to
0.6
ohms at 68OF
(2OOC).
Testing
for Grounds:
Connect leads of ohmmeter between each
CR
lead
and exciter rotor laminations; use
RX
100 scale on
ohmmeter.
An
ohmmeter reading less than infinity
(00)
indicates defective ground insulation.
TESTING GENERATOR ROTOR
For these tests, use an ohmmeter on
RX
100 scale.
Testing
for
Grounds:
On brushless type generators, check for grounds
between each rotor lead and the rotor shaft, Figure
14. Perform tests as follows:
1.
Remove rotor leads F1+ and F2- from rotating
rectifier assemblies.
2. Connect ohmmeter leads between F1+ and rotor
shaft and between F2- and rotor shaft. Meter
should not register.
3. If meter registers, rotor is grounded.
4.
Replace grounded rotor with new, identical part.
Testing
for
Open
or
Shorted Winding:
All
resistancevalues should be within
rfr
10%of
values
specified
in
Tables 2 and
4
at
77OF
(25°C).
Perform
tests
as
follows:
1.
Remove rotor leads F1+ and F2- from rotating
2. Using ohmmeter, check resistance between F1
rectifier assemblies.
and F2 leads, Figure 15.
If
resistance
Is
low,
there
are
shorted
turns.
If
resistance
is
hlgh,
rotor
winding
Is
open.
In
either
case,
rotor must
be
replaced.
3.
Replace defective rotor with new, identical part.
OHMMETER
-
CONTACT
ONE PROD TO ONE FIELD LEAD
AND
OTHER
PROD
TO
OTHER FIELD LEAD.
RESISTANCE
VALUES ARE GIVEN
IN
TABLES
2
AND
4.
8273
FIGURE
15.
TESTING
ROTOR
FOR AN OPEV CIRCUIT
15
TABLE
2
RESISTANCE VALUES
FOR
ROTORS Testing
for
Open
or
Shorted
Windings:
~
RESISTANCE
’
OHMS@2S°C(77V)
245
-
2.50
245
-
2.50
276
-
282
276
-
282
2.05
-
2.09
2.30
-
235
230
-
2.35
230
-
2.35
230
-
2.35
250
-
255
250
-
255
250
-
2.55
250
-
255
250
-
255
270
-
275
kW
RATING
50
HERTZ
4.5
DJB
4.5
DJE
6.0
JB
6.0
MDJE
-
-
-
9.0
DJC
10.0
MDJC
125
JC
125
RJC
125
RDJC
120
MDJF
14.5
RDJF
-
AND
MODEL
60 HERTZ
6.0
DJB
6.0
DJE
7.5
JB
7.5
MDJE
10.0
MJC
125
JC
125
RJC
12.0
DJC
120
MDJC
15.0
JC
15.0
MJC
15.0
RJC
15.0
RDJC
15.0
MDJF
17.5
RDJF
TESTING GENERATOR STATOR
Using proper test equipment, check the stator for
grounds, opens, and shorts
in
the windings.
kW
RATING AND MODEL
50
Hertz
60
Hertz
.
4.5DJB 6.0 DJB
4.5 DJE 6.0 DJE
6.0
JB 7.5 JB
6.0
MDJE 7.5 MDJE
10.0 MJC
12.5 JC
12.5 RJC
9.0 DJC 12.0 DJC
10.0
MDJC 12.0 MDJC
12.5 JC 15.0 JC
15.0 MJC
12.5 RJC 15.0 RJC
12.0 RDJC 15.0 RDJC
12.0 MDJF 15.0 MDJF
14.5 RDJF 12.5 RDJF
Testing
for
Grounds:
Some generators
have
ground
connections
to
the frame.
Check
wiring diagram.
.Using an ohmmeter set at
RX
100, test each stator
winding for shorts to laminations.
A
reading less than
one megohm indicates a ground.
18
-695
.695
.460
.460
.340
.303
-303
.303
.303
.220
.220
-220
.220
.220
.162
Test for continuity between coil leads shown
in
Fig-
ure 16; all parts should have equal resistance. Use an
accurate instrument for this test such as a Kelvin
Bridge. The proper resistance values for J-Series sets
are given
in
Table 3 according to kW ratings and
voltage codes.
All
resistances should be
+:
10%
of
value shown at 68’ F
(2OOC).
Table 4 has resistance
valuesfor PTOalternators in the 15-25 kWsize range.
If any windings are shorted, open
or
grounded,
replace the stator assembly. Before replacing the
assembly, check the leadsfor broken wires or insula-
tion.
51 8
-761
.761
.498
.498
-
-
-
.260
.260
.198
-
.198
.198
.198
.143
FROM
KELVIN
3c
-360
-360
.224
-224
-172
-120
.120
.120
-120
-087
-087
-087
.087
-087
-066
A/
BRIDGE
TI-T4 T7-TIO T3-Tb
.
T9-TI2 TZ-TS
=TI1
t
THREEPHASEMODELS
TEST BETWEEN
WIRE
PAIRS
SlNGLE PHASE MODELS
TEST BETWEEN WIRE
PAIRS
TI-T2 TST4
FIGURE
16.
TESTING
STATOR
WINDINGS
TABLE
3.
RESISTANCE VALUES FOR STATORS
53c
-485
.485
-294
.294
-
-
.153
.153
-110
.110
.110
.110
-089
-
I
I
I
I
I
I
.
16
COl
VOLTAGE
OHMS
Q
77'F
(25OC)
CODE ROTOR STATOR
3c
2.77
-
2.35
0.095
1
3c
2.70
-
2.75 .063
-
.076
-219 Tl-T2, T2-T3,
.
1
42 T1 -TO, T2-TO
5D
2.70
-
2.75 Tl-T3
.248 T3-TO
3c 1.800
-
0.095
0.170 Tl-T2, T2-T3,
5D
1.800
-
T3-Tl
0.106 Tl-TO, T2-TO
0.192 T2-TO
PI
WIRING HARNESS CHECK
Carefully check wiring harnesses as follows:
1.
Inspect all wires for breaks, loose connections,
and reversed connections. Refer to applicable
wiring diagram.
2.
Remove wires from terminals at each end and
using an ohmmeter, check each wire end to end
for continuity or opens.
3.
Using an ohmmeter, check each
wire
against
each of
the
other
wires
for possible shorts
or
insulation breaks under areas covered by wrap-
ping material.
4.
Reconnect or replace
wires
according to
applicable wiring diagram.
VR21
REPLACEMENT
Use the following procedure for replacing the voltage
regulator
PC
board.
1.
Stop engine.
2.
Disconnect and
if
necessary, label the following
3.
Remove four screws at corners.
4.
Remove
used
PC board.
5.
Install
new
PC board; secure
with
four screws.
6.
Reconnect wires removed
in
step
2
at the proper
terminals.
7.
Place
jumper
W10
at proper terminals for your
particular voltage code and voltage connection.
See
Figures
17
and
19.
8.
Perform Voltage Calibration and Stability
Ad-
justment procedures
[A]
and
[B]
to obtain the
correct generator output voltage and stability
with new PC board
in
set.
wires:
3,
4,
5
or
6,
7, 8, 9,
and
10.
,
TABLE
4.
RESISTANCE VALUES
FOR
PTO ALTERNATORS
PTO
MODELS
15.0
kW
l-Phase
.
20.0
kW
l-Phase
20.0
kW
$Phase
25.0
kW
l-Phase
25.0
kW
$Phase
17
Figure
17
shows the above components for typical
control boxes. The electrical schematic and printed
circuit board are shown in Figure 18.
VOLTAGE REGULATOR
The line-voltage regulator assemblies VR22 and
VR23
On
the J-Series generator Sets are solid state
devices. Basic components are:
Printed circuit board VR21
Voltage reference transformer T21
Commutating reactor CMR21
Field circuit breaker CB21
Voltage adjust rheostat R22 (Optional)
The voltage adjust control R22
is
optional on either
VR22 or VR23 voltage regulator. When R22 isased, it
is connected between VR21-1 and VR21-3 (Figure 17)
and the jumper between VR21-1 and VR21-2 is
removed.
REMOVE
JUMPER
WHEN
OPTIONAL VOLT-
AGE
ADJUST CONTROL
IS
USED
/
./
WIO
VR22
(W/O VOLT ADJ
Y
J
VR23
(W/VOLT
ADJ)
VOLTAGE
(OPTIONAL)
ADJUST
-
CB2
I
\
VR21
C
.FEU)
)-I
L-
N0TE:FIEU)
BREAKER BREAKER
IS
MOUNTED
ON
PANEL
/
REFERENCE
TRANSFORMER REACTOR
VOLTAGE COMMUTATING
AIR-COOLED
AND
8203
MARINE
SETS
RADIATOR-COOLED
SETS
FIGURE
17.
STANDARD YD VOLTAGE REGULATOR
ASSEMBLIES
.
REGULATOR SCHEluqnC
R25
R24
R23
R22
DES.
I
DESCRIPTION
721
I
Transformer.
Ref
Voltare
MSISTOR-FIU
42.2Rn.
1/41
48.4KlI.
1/4V
"
I,
RESISTOR
Ion.
Iln
RESISTOR
2705
)r
RIB
RIG
AI5
11'
R14
R13
RI
1.
I2
R9
AB
10
R7
R6
R5
R3
RZ
R4
I
IRESISTOR-FILY
2
67K
1/11
RfSIST(w
FILM
21.01.
I/*
RESISTOR
IBKd
IW
33n.
I
121
RESlSTllR
.
am.
t/n
RESISTOR-FIW
irom.
1/41
RESISTOR-IIRF
WOUWO
4Kn.
¶1
RESISTOP
I
RM.
112W
RESISTOP
IOOKIl.
1M
270M.
IRI
RESISTOR-FILY
I.ZW.
I/N
RESISTOR
2
UE6n.
i/n
RES
I
STOR
3M.
1/21
a3wn.
rm
220m.
tin
Rl
I-
33KL
1/21
nz
1
TRANSISTOR-UIIIJUHCTION
.
RECTIFIER-GATE
CONI
CR5
IW
cR3.4.6-I
11
RECTI
FI
ER-OI
WE
Id.
400V
I
I
0IO;E-ZEHER
2oY
5.w
CAPACITOR
.47MmlOW
CAPACITOR
3YFO
z!i4&
lYF0
'.lUFOZSORI
8787
om(1387
IO(Yllm9
+aM-T
-1-1
PRINTED
CIRCUIT
BOARD,
VR21
NOTE:
The
2500ohm
external voltage
adjust
potentio-
meter
connects
between
pin
I
and
pin
3.
See
regulator
schematic.
If
your
set
does
not have an external
voltage adjust potentiometer,
pin
I
is
jumpered
to
pin
2.
FIGURE
18.
STANDARD YD
REGULATOR
PC
BOARD
300-1540
19
1
VI
v2
v3
v4
VI
v2
v4
-
VI
v2
\R
v4
VI
SCHEMATIC
MAGRAM
240
5
J
LI
y
i2
WIRING
DIAGRAM
CONNECT
XI
TO
VRZI-5 FOR
50
HERTZ: CONNECT
XI
TO
VR21-6 FOR
60
HERTZ
GENERATORS.
T4
h
T7
R
K
TI0
T5
A.
T8
T3
1
TI1
T6
A
T9
TI
A
TI2
TI
~~~
l7
T6
TI2 T3
T9
T5
Tll
T4
TIOR
T8
LI
u
L3
LO
TIRT3TO
FIGURE
19.
GENERATOR WIRING AND RECONNECTION DIAGRAMS
4.5
-
25
kW
(CODE 5D
PTO
UNITS SEE PAGE
34)
20
*
PART
II
TROUBLESHOOTING
PROCEDURES
(YD
GENERATORS USING
UR
REGULATOR)
The information in this section is for generators used
on 25DTA/MDTA series sets and the 30kW PTO and
SKsets. Information is divided into
Flow
Charts, A, B,
C, D and E as follows:
A.
NO
AC OUTPUT VOLTAGE AT RATED ENGINE
B.
UNSTABLE OUTPUT VOLTAGE, ENGINE
C. OUTPUT VOLTAGE
TOO
HIGH OR LOW.
D. EXCITER FIELD BREAKER TRIPS.
RPM.
SPEED STABLE
1800
RPM.
E. UNBALANCED GENERATOR OUTPUT VOLT-
'
AGE.
To troubleshoot a problem, start at upper-left corner
of the chart related to problem, and answer all ques-
tions either YES
or
NO. Follow the chart
until
the
problem is found, performing referenced Adjustment
and Test procedures following the Flow Charts.
Referenced components
in
the Flow Charts and
Adjustment and Test procedures can be found on the
electrical schematic Figure
20,
and on assembly
drawings
and
wiring diagrams
on
pages
32-34.
GENERATOR
OPERATION
The basic operation of the generator and AC controls
involves thestator, voltage regulator, exciter field and
armature, afull wave bridge rectifier,
and
the genera-
tor rotor, Figure
20.
Residual magnetism
in
the gen-
erator rotor and a permanent magnet embedded
in
one exciter field pole begin the voltage build-up pro-
cess as the generator set starts
running.
Single-
phase AC voltage, taken from the stator windings, is
fed to the voltage regulator as a reference voltage
for
maintaining the generator output voltage. The AC
reference voltage is converted to
DC
by
a
silicon
controlled rectifier (SCR) bridge and fed into the
exciter field windings. The exciter armature produces
three-phase AC.voltage that is converted to DC by the
rotating rectifier assembly. The resultant
DC
voltage
excites the generator rotor winding to produce the
stator output voltage for the AC
load.
The
SCR
bridge is encapsulated
in
a hermetically
sealed block. Therefore, if any diode or silicon con-
trolled rectifier fails, the entire bridge has to be
replaced.
I
ASSEMBLY
I
ES1067
FIGURE
20.
ELECTRICAL SCHEMATIC,
YD
GENERATOR
WITH
TYPE UR REGULATOR
21
START
Replace defective
field breaker.
and check continuity with
ohmmeter.
Is
breaker open?
Is
control panel field
breaker CB21
ON?
no
A
ti0
I
v
I
1
4
I
I
Push to reset breaker. Does generator
AC output voltage build up?
I
If voltage is unstable, high or
low,
or
causes breaker to
trip,
see
Flow Charts
B.
C, D. or
E
t
-t-l
P
I
I
I
I
no
I
-1
t
Is
residual voltage across 1621-62 and
63
5
to
10
VAC or more? Flash exciter field per TEST [D].
Does
generator output voltage build up?
Disconnect stator leads 7 and
8
from
TB21-62
and
63.
Is
residual voltage across leads
5
to
10
VAC or more now?
Check reactor L21 and transformer T21 per
TESTS
[B] and
[E].
Is
exciter field voltage
across VR21-5
&
6 5
VDC
Check exciter field wiring
for
opens per TEST
[MI.
Replace bad wiring.
Check exciter field winding
per TEST [HI. Replace
if bad.
Check diodes and SCR's on
bridge assembly CR21 per
TEST [C].
Check fuses F2 and F3 for
continuity on VR21
regu-
Check exciter field wiring
for
shorts per TEST
[MI.
Replace bad wiring.
v
Replace voltage regulator
PC board per procedure IF].
Do
not
replace the
printed circuit
board
until
the trouble
not on
the
PC
board
has
been
located and
corrected
to
avoid damage
lo
new
PC
board.
I
Check lead continuity between
VR21-12
&
l7
on generator,
I
Check diodes CR1 through CR6
on rotor per TEST
[GI.
Re-
I
Check exciter rotor winding
per TEST [J]. Replace if bad.
I
'
22
FLOW CHART
B.
UNSTABLE VOLTAGE,
ENGINE
SPEED STABLE
1800
RPM
Are there any broken wires or loose connections
on voltage regulator assembly?
START
--Yes
-
Repair as required.
i
<
Check wiring harness from regulator assembly
to end
bell
per
TEST
[MI.
Check
OK?
Repair wiring or replace
as
required.
~~ ~~~
Does adjustment
of
Dampening Control R26 on VR21
per adjustment
[PI
result in stable
voltage?
yes
J-
Is
voltage stable within spec at no
--Yes-
.
load to full load range
of
generator
set?
-
no---,
Is
engine running at correct
RPM?
Replace voltage regulator
PC
board per
procedure
[F].
Set
RPM
per instructions
in
appropriate
engine manual.
Do
not replace the
printed
circuit board
untll the trouble not on the
PC
board has
_I
been located and corrected to avold damage to new
PC
board.
Are
reference transformer (~21) tap connections
correct and secure on
TB22?
See
TEST
IO].
w
FLOW
CHART C. OUTPUT VOLTAGE TOO HIGH
OR
LOW
Are generator output leads properly connected?
See Figure
36,
page
34.
START
Does adjustment
of
Voltage Adjust control
R21 on VR21 result in correct output Set control pervoltage Calibration
Adjustment
[PI.
I
I
I
1
t
Does adjustment
of
control R18 on VR21 result
in correct output voltage?
I I
Set per Voltage Calibration Adjustment
[PI.
I
I
I
I
I
Do
not replace the prlnted clrcult board
until
the trouble not
on
the
PC
board has
been located and corrected to avold damage to new
PC
board.
’
f
I
Replace voltage regulator
PC
board VR21 per
procedure
[F].
23
.
FLOW
CHART
D.
EXCITER
Does AC output voltage build
up
to 150% or
more of rated voltage before breaker trips?
START
I
t
-yes- Check for any
loose
or broken wires or connections
on VR21 assembly.
FIELD
BREAKER
TRIPS
*
I
i
Check generator stator windings per TEST
[K].
Replace
if
bad.
I
no
I
Check diodes CR1.2,3.4,5 and
6
in
rotor assembly
per TEST
[GI.
Replace
if
bad.
1
Check exciter stator winding per TEST
[HI.
Replace if bad.
Check exciter rotor winding per TEST
[J].
Replace if bad.
I
t
I
i
I
Check diodes and
SCRs
in bridge assembly
CR21 per TEST
[C].
Check.generator
stator
leads for proper,
connection. See Figure
36,
page
34.
I
I
Check generator rotor field winding per
TEST
[L].
Replace
if
bad.
I
I
I
I
I
DO
nOf
tephCt?
the
pdnted CirCUlt board
until
the
trouble not
on
the
PC
board
has
bcen
located
and
corrected
to
avold
damage
to
new
PC board.
I
I
Replace voltage regulator PC board
VR21
per
procedure
[F].
24
FLOW CHART E. UNBALANCED GENERATOR OUTPUT VOLTAGE
START
Remove load at generator terminals.
Is
output
still
unbalanced? and load.
Check for correct grounding of generator
Yes
I
.
I
I
1
tno-l
Are generator leads connected and grounded
properly?
See
Figure
36,
page
34.
I
I
Correct
as
necessary.
I
I
t
I
Is
generator stator winding
continuous
per
TEST
[K]?
Replace stator assembly.
Check
load for ground faults and
correct
as
necessary.
25
ADJUSTMENTS AND
TESTS
(YD
GENERATORS USING
UR
TYPE REGULATORS)
GENERAL
All of the following Adjustments and Tests can be
performed without disassembly of
the
generator.
They should be used for testing generator and regu-
tator components in conjunction with the trouble-
shooting flow charts.
TESTCNG
AC RESIDUAL VOLTAGE
.
Generator residual
AC
voltage should be checked
first
if
there is no
AC
power output.
A
quick place to
check
is
at
TBzl
across terminals 62 and
63
(see
Figure
20).
Residual voltage should
be
5-10
VAC.
If
none,
flash
field
pet
Test
[D].
if residual voltage is present at TB21, then check
circuit breaker CB21. If CB21 is
OK,
proceed to VR21
PC board and check for residual voltage between
connector numbers
11
&
12,1& 2, and
9
&
10. If none,
check continuity between these points with the gen
set shut down. If voltage is low, check L21 reactor
(Test
[B]
and
T21
transformer (Test
[E]).
TESTING.
L2f REACTOR
The t21 eommutating reactor (Figure
21)
mounts
inside the control
box
The
coils
1-2
and
3-4
are wound on the same core.
Resistance between 1-2 and
3-4
should be .031 to
,037and
.037to
.046 ohms respectivelyat 77OF (25').
Resistance between coils and from any terminal to
frame
of
the reactor should be infinity.
rc1
TESTING
RECTIFIER BRIDGE
ASSEMBLY (CR21)
The rectifier bridge located within the control cabi-
net, contains
3
diodes,
CR1,
CR2
and
CR3,
and two
silicon controlled rectifiers, SCRl and
SCR2.
The
components are encapsulated within a hermetically
sealed block, therefore failure of any diode'or
SCR
means the entire unit has to be replaced.
See
Figure
22.
FIGURE
21.
L21
REACTOR
AC
TERMINALS ARE
GIVEN
NUMERIC
'
DESIGNATIONS
FOR
Tf3T
REFERENCE
ONLY.
DOES
NOT
v
APPEAR
ON
UNIT.
CRI
I
I
C)
FIGURE
22
RECTIFIER BRIDGE
ASSEMBLY
Disconnect wires from rectifier unit prior to testing.
Test unit in order shown in Table
5.
Refer to Figure
23
for SCR1 and SCR2 test circuit. When test is
com-
plete and satisfactory, reconnect unit observing cor-
rect wiring hook-up.
26
L....
DRY
ELL
BATTERY
TEST
FIGURE
23.
TESTING
SCR
OHMUEERLEAD
RECTlFIER
TEmNG
+
-
TERMINUS
CR
ISCR
REMARKS
METER
SCUE
1x
+u13
Infmily
RXlOK
X
TABLE
5.
TESTING RECTIFIER BRIDGE
ASSEMBLY
CR21
3x
+
SCRl
I"f#lir,
RXlOK
X IC1
9'
6
V
Ds.tu*
DCVdPnckf
DC
VOmMn
lmd
R..dh9
+
less
lhan
rrlh
Ralrbr
+-
AC1
+
SCRl
ACl
1
+
3
VOID
Infmily
RXlOK
ACI
+.
SCRZ
lnfintly
RXlOK
lo"
141x
x~~v
I
I
I
I
Infmily
RXlOK
AC2
+
SCRZ
AC?
+
3
VOID
5x
-
CRl RXl
x
ACI
6X
+.
SCRZ
lnfintly
RXlOK
xmr
-
FLASHING THE FIELD
If output voltage does not build up
it
may be neces-
sary to restore residual magnetism by flashing the
field. Assemble a &volt battery and diode as shown in
Figure
24.
If a &volt lantern battery is not available, a 12-volt
or
24-volt generator set battery can be used. However,
a
20-ohm
or
a &ohm, 2 watt resistor must be used in
-
series respectively with the 12amp
300
Vdiode. Start
the generator setand operate at normal rpm. Touch
positive lead to
+
terminal on rectifier bridge, and
negative lead to the
-
terminal. Hold leads on termi-
nals just long enough for voltage to
build
up.
CAUTION
DO
not
keep
excitation circuitry connected
Ex
longerthan BseconL,ordamage
may
occur
to
the
exciter
regulator.
.
PLACE
RESISTOR
HERE
FOR
12V
OR
24V
BATTERY
RECTIFIER
BRIOGE
ASSEMBLY
6
VOLT
DRY
CELL
BATERY
FIGURE
24.
FIELD FLASHING
CIRCUIT
TESTING REFERENCE
TRANSFORMER
T21
Transformer
T21
has eight leads; six are primary
leads marked
H1
through H6, two are secondary
leads marked X1 and X2.
27
The winding schematic (Figure 25) shows the resist-
ance values for the individual coils
in
ohms. Resist-
ance between any primary and secondary leads and
from any lead to transformer frameshould be infinity.
m
531-649 OHMS
Tzl
x1
vR21-9 x2 vR21-10
FIGURE
25.
T21 WINDING SCHEMATIC
..
VR21
REPLACEMENT
Usethe following procedure for replacing the voltage
regulator PC board
or
VI?
chassis.
1.
2.
3.
4.
5.
6.
7.
8.
Stop engine.
Disconnect and
if
necessary, label wires: VR21-1
through VR21-12 Refer to AC control wiring
diagram.
Remove four screws at corners.
Remove
old
PC board.
Install new PC board; secure with four screws.
Reconnect wires removed
in
step
2
at proper
terminals.
Place jumper
W12
at proper terminals for your
particular voltage code and voltage connection.
See Test Procedure
[Q].
Perform voltage calibration and stability adjust-
ment procedures to obtain the correct generator
output voltageand stability with new PC board
in
set.
TESTING ROTATING RECTIFIERS
’
Two
different rectifier assemblies make up the rotat-
ing rectifier bridge assembly, Figure 26. Using an
accurate ohmmeter, test each CR using negative and
positive polarities. Test rectifiers
as
follows:
1.
Disconnect all leads from assembly to be tested.
2.
Connect one test lead to F1+ stud and connect
other lead to CRl, CR2, and CR3 in turn; record
resistance value of each rectifier.
3. Connect one lead to F2- stud and connect other
lead to CR3, CR4 and CR5 in turn; record resist-
ance value of each rectifier.
4.
Reverse ohmmeter leads from step
2
and record
resistance value of each rectifier F1+ to CRl,,
CR2, and CR3 and F2- to CR4, CR5, and CR6.
5.
All
three resistance readings should be high in
one tedand low in the other test. If any reading is
high or low in both tests, rectifier assembly is
6.
Replace defective rectifier assembly with new,
c
. . defe,ctive.
identical part.
Use 24ibr-h.
(2.7
Nom)
torquewhen replacing nutsof Fl+and F2-,
CRl, CR2, CR3, CR4, CRS, and CR6.
CR3
FIGURE 26. TESTING ROTATING RECTIFIERS
[HI
TESTING EXCITER STATOR
Test the exciter stator (Figure 27) for open or shorted
windings and grounds as follows:
Testing for Open or
Shorted
Windings:
Disconnect F1+ and
F2-
exciter field leads from ter-
minal block in generator end bell. The resistance
between field leads should be 13.05
to
15.95 ohms at
77’ F (25OC).
Testing
for
Grounds:
Connect ohmmeter between either field lead and
exciter stator laminations. Use ohmmeter set at RX
100
scale. An ohmmeter reading of
less
than infinity
(
Di
) indicates defective ground insulation.
1
-
28
kW
RATING
60
Hertz
DTAIMDTA
25.0
kW
SK
30.0
kW
PTO 30.0
kW
OHMMETER RESISTANCE BETWEEN
Fl
AND
F2
SHOULD
BE
13.05
TO
15.95
OHMS AT
77'F
(25°C)
VOLTAGE CODE
75
3c
-066
to .081
.a99
to
-121
Code
50
.031
to
-038
-027
to
-033
Ohms Ohms
Ohms
Ohms
Tl-T2, T2-T3, -032
to
.039
T3-Tl
.149to
Ohms
.183
Ohms
FIGURE
27.
TESTING EXCITER FIELD
IJI
TESTING EXCITER ROTOR
Test the exciter rotor (Figure 28) for open or shorted
windings or grounds as follows:
Testing for Open or Shorted Windings:
Use a Wheatstone Bridge for this test. Disconnect
main rotor field leads which connect to rotating recti-
fier assemblies at
F1+
and
F2-.
Disconnect lead wires
from diodes CR1, CR2, CRq, CR4, CR5and CR6.Test
between exciter lead pairs Tl-T2, T2-T3 and Tl-T3.
Resistance should be
0.6
to
0.7
ohms at
68"
F
(2OOC).
Testing for Grounds:
Connect leads
of
ohmmeter between each
CR
lead
and exciter rotor laminations; use
RX
100 scale on
ohmmeter. An ohmmeter reading less than infinity
(..)
indicates defective ground insulation.
FI
CRS
FIGURE
28.
TESTING EXCITER
ROTOR
TESTING
GENERATOR
STATOR
Using proper test equipment, check the stator for
grounds, opens, and
shorts
in the windings.
Testing for Grounds:
Some generatots
have
ground connections
to
the
frame.
Check
wiring diagram.
Using an ohmmeter set at
RX
100, test each stator
winding for shorts to laminations. A reading lessthan
one megohm indicates a ground.
Testing for Open or Shorted Windings:
Test for continuity between coil leads shown
in
Fig-
ure 29; all pairs should have equal resistance. Use an
accurate instrument for this test such as
a
Kelvin
Bridge. Resistance valuesat 77'
F
(25OC) are given
in
Table 6.
If
any windings are shorted, open or grounded,
replace the stator assembly. Before replacing the
assembly, check the leads
for
broken wires or insula-
tion.
THREE PHASE MODELS
TEST BETWEEN WIRE PAIRS
29
CONTACT
ONE
PROD
TO
EACE
OF
ME
FIELD
LEADS
AND
OTHER
PROD
TO
ROTOR
SHAFT.
IF
ROTOR
IS
GOOD. THERE
WILL
BE
NO
CONTACT
ONE
PROD
TO
EACH
FIELD
LEAD
8215
READING
ON
OHMMETER.
8213
FIGURE
30.
TESTING ROTOR FOR GROUNDS FIGURE
31.
TESTING ROTOR
FOR
AN OPEN CIRCUIT
TESTING GENERATOR
ROTOR
For these tests, use an ohmmeter on
RX
100
scale.
WIRING HARNESS CHECK
Carefully check wiring harnesses as follows:
Testing for Grounds:
On brushless. type generators, check for grounds
between each rotor lead and the rotor shaft, Figure
30. Perform tests as follows:
1.
Remove rotor leads
F1+
and
F2-
from rotating
rectifier assemblies.
2. Connect ohmmeter leads between
F1+
and rotor
shaft and between F2- and rotor shaft. Meter
should not register.
3.
If meter registers, rotor is grounded.
4. Replace grounded rotor with new, identical part.
Testing
for
Open or Shorted Winding:
Perform tests as follows:
1.
Inspect all wires for breaks, loose connections,
and reversed connections. Refer to applicable
wiring diagram.
2.
Remove wires from terminals at each end and
using an ohmmeter, check each wire end to end
for continuity or opens.
3. Using an ohmmeter, check each wire against
each of the other wires for possible shorts or
insulation breaks under areas covered by wrap-
ping material.
4.
Reconnect or replace wires according to appli-
cable wiring diagram.
.
1.
Remove rotor leads
F1+
and
F2-
from rotating
rectifier assemblies.
SENSITIVITY REFERENCE CIRCUIT
2. Using ohmmeter, check resistance between
F1
and
F2
leads, Figure
31.
Theresistancevaluesat68°F
(2OOC)
should beas
follows:
1.84to 2.24ohmsfor25DTNMDTAand 30kW
1.62 to 1.98 ohms for 30 kW
SK
models.
PTO
models.
If
resistance
is
low,
there
are
shorted
turns.
If resistance Is
high, rotor winding is open.
In
either
case,
rotor must
be
replaced.
3.
Replace defective rotor with new, identical part.
Three types
of
frequency sensitivity reference voltage
are possible with voltage regulator VR21.
1.
frequency sensitive-voltage output reduces in
direct proportion to the engine speed.
2.
Non-frequency sensitive-voltage output does
not decrease when engine speed decreases.
A
temporary overload with a non-frequency sen-
sitive reference could cause the engine to reduce
speed, and then require a
50-
to 60-percent load
reduction before
it
could return to rated speed.
3.
Semi-frequency sensitive
-
voltage output
decreases as engine speed decreases, but not as
.#
.)
30
severely as
in
the "frequency sensitive" mode.
Unless otherwise requested by the purchaser,
Onan
sets
are connected
at
the
factory
for
semi-
frequency sensitive voltage regulation because a
decrease
in
voltage output reduces the effective
load on the engine, permitting the set to return to
its rated voltageand frequency when the overload
is removed.
CHANGING SENSITIVITY REFERENCE
The sensitivity reference can be changed if
necessary, by unsoldering W1 on VR21 at
"S'
(semi-
frequency sensitive) and resoldering itto ho1e"F" (for
frequency sensitive)
or
to hole
"N"
(for non-
frequency sensitive) voltage regulation.
See
Figure
32.
I
1
FIGURE
32
REGULATOR
CIRCUIT
BOARD
VOLTAGE ADJUSTMENT
After replacement
of
the regulator printed circuit
board (VR21), voltage adjustment is performed as
follows (see Figure
32):
1.
Center the voltage adjust knob
so
pointer is in a
vertical position.
2.
Start
unit
and operate at correct rpm.
3.
Using a screwdriver, turn R18 potentiometer on
printed circuit board
VR21
counterclockwise to
decrease
the
voltage
or
clockwise
to
increase the
voltage. Observe voltmeter on meter panel while
making adjustment. Set voltage with no load
connected to generator. (ExarnplcFor
a
120/240
volt connection, set at no-load voltage
or
ap-
proximately
246
volts.)
If voltage
is
unstable
or
tends to hunt, turn
R26
potentiometer on VR21
in
the
direction shown on
printed circuit board to increase voltage sensitivity.
-w2
NOTE
SEE
VOLTAGE
CHART
FIGURE
36
0
L
P
.I
CONNECT
LOOSE
WIRE
FROM
TERMINAL
#63
1
TO
EITHER
H3, H4, H5
OR
H6
DEPENDING
ON
VOLTAGE
SELECTED.
30
kW
PTO
AND
SK
SETS
I
CONNECT
LOOSE
WIRE
FROM
TB2-2
TO TB2-
HI,
HZ
H3,
H4.
H5
OR
H6
DEPENDING ON
VOLTAGE
SELECTED.
1
m2
25
kW
DTA
SETS
FIGURE
33.
CONNECTING
LOOSE
WIRE
W12
I
31
[a1
RECONNECTION
WIRE
W12
VOLTAGE
REGULATOR
The voltage regulator assembly (Figure 34) controls
the generator AC output. Basic components
of
the
regulator are:
Printed circuit board VR21
Voltage reference transformer T21
Commutating reactor L21
SCR bridge rectifier CR21
Figure
36
shows reconnection possibilities for the
generator. When reconnecting for a different voltage,
be sure to also reconnect lead W12 (inside control
box) to the proper
H
terminal
as
shown in Figure
33.
On the
SK
series generator sets,
T21,
CR21 and L21
are mounted to the control box inside panels close to
the VR21 printed circuit board.
.
Thevoltage regulator printed circuit board and sche-
matic diagram are shown in Figure 35.
\
PC
BOARD
VR21
VR
MOUNTING
PANU
TERMINAL
BLOCK
TB2
VOLTAGE TRANSFORMER
SCR
BRIDGE
CR21
COMMUTATING
REACTOR
RESISTOR
ASSEMBLY
T21
L21
FIGURE
34.
VOLTAGE REGULATOR ASSEMBLY
305-0579
32
4
REF.
NO.
C1.14
c2. c7
c3
c4.
c12
c5.
c8
G6
c11
C13
CR3
CR12
CR13
CR14
Thnr
11
F2. F3
1c1
Q2
Q3
Rl
R2. R3
R4
A5
R6
R7
R8.
R16
R10
R11
R9
R12
R13
R14
R15,
R27
R17
R18
R20.22
R21
R24
29
&
30
PART
DESCRIPTION
Board
Assembly,
Printed
-
Capacitor
-
A7
Mfd,
250
Volt
Capacitor
-22
Mfd.
250 Volt
Capacitor -A7
Mfd.
400
Volt
Capacitor -.47
Mfd,
250 Volt
Capacitor
-
1
Mfd.
100 Volt
Capacitor
-
.33
Mfd,
250
Volt
Capacitor
-
1
Mfd.
400 Volt
Capacitor
-
Electrolytic
Rectifier
-
Silicon
Diode
-
Zener
5.6
Volt
Diode
-
Zener 20 Volt
Diode -Zener 18 Volt
Fuse
114 Amp
Integrated Circuit
Transistor
-
Silicon
NPN
Transistor
-
Unijunction
Resistor
-
112 Watt, 47-0hm
Resistor
-
112 Watt, 33-0hm
Resistor
-
2 Watt, 4.7 Meg-Ohm
Resistor
-
Fixed
10 Watt,
Resistor
-
Fixed
15
Watt,
Resistor
-
112 Watt, 3.000-0hm
Resistor
-
112 Watt, 330.000-0hm
Resistor
-
112 Watt, 51.100-0hm
Resistor
-
Fixed3 Watt,
Resistor
-
112 Watt, 90,900-0hm
Resistor
-
112 Watt, 10.000-0hm
Resistor- 112 Watt. 220,000-0hm
Resistor- 1RWatt. 100.000-Ohm
Resistor, Metal Film
-
114
Watt,
11.000-0hm
Potentiometer-5,0hm. 112 Watt
Resistor
-
114 Watt, 28.000-0hm
Resistor
-
Metal Film
-
114 Watt, 5.1 1 Whm
Resistor
-
Metal Film
-
114 Watt, 8,870-0hm
Complete
100
Mfd.
10 Volt
27Whm
5.000-0hm
15,000-0hm
REF.
NO.
PART
DESCRIPTION
R25,
R31
R26
Potentiometer
-
112
Watt,
1W.000-0hm
R28
TBl Terminal
Block
CR15
K1 Relay, Magnetic
Reed
R19
Resistor
-
2
Watt. 10,000-Ohm
Resistor
-
1f2 Vdatt -47
Meg-Ohm
Diode
-
Zener
-
24 Volt
Clip
-
Fuse
Resistor
-
2 Watt, 6.8009hm
1
PC
BOARD ASSEMBLY
//.%a
-
--
---
SCHEMATIC
ES-1068
FIGURE
35.
UR VOLTAGE REGULATOR
PC
BOARD
332-1956
33
1201240
VOLT,
1
PHASE,
60
HERTZ
NAMEPLATE
VOLTAGE
CODE
3
1-
Lo
L2
1201240
VOLT, DELTA
3
PHASE,
60
HERTZ
NAMEPLATE
VOLTAGE
CODE
5D
l------
L1
LO
L2
P
I
1
L3
I
3471600
VOLT,
3
PHASE,
60 HERTZ
I
NAMEPLATE
VOLTAGE
CODE
9X
TI
TO
c
CONNECT
LEAD
W12
TO
H5TERMlNAL
I
.
TO
12
LEAD GENERATORS ONLY
GENLRATOR
CONNECTION WIRING DIAGRAM
(WITH
CURRENT TRANSFORMERS
WHEN
USED)
LO
11
12
11
12
16111
18112
14
19
15
17
13
110
LO
11
12
13
11
110
16
17
12
111
14
18
13
112
15
19
LO
11
12
13
LO
11
12
13
1101li 112
11
17
14
12
18
75
13
19
1
FIGURE
36.
GENERATOR
WRING
AND
RECONNECTION DIAGRAMS
(25DTAM#DTA,
30 kW
-0
AND
SK
SERIES)
I
34
GENERATOR
REPAIR, J-SERIES
r’
COOLINGAIR
FIGURE
37.
GENERATOR
AIR
OUTLET
DISASSEMBLY
1.
Disconnect battery to prevent accidental starting
of engine.
2.
Remove end bell cover to reveal rotor-through-
stud nut.
3. Remove
B1
lead from tapped adjustable resistor
in generator air outlet opening, Figure 37.
4.
Remove leads from control box to ignition sys-
tem, choke, start disconnect switch, etc., on
engine.
5.
Remove stator-through-stud nuts, end bell, and
ADAPTER
stator assembly, Figure
38.
Screwdriver slots in
adapter provide
a
means for prying stator loose.
Be careful not to
let
statortouch or drag on rotor.
6.
Remove
air baffle from adapter. Turn rotor-
through-stud nut to end of stud. While pulling
rotor outward with one hand, strike nut a sharp
blow. Support rotor with hoist and sling to avoid
bending rotor-through-stud, Figure 39.
Use
a
heavy, soft faced hammer to loosen the rotor from
its tapered shaft fit.
If
rotor does not come loose,
strike
it
asharp downward
blow
in center of lami-
nation stack. Rotate rotor and repeat until
it
comes loose. Be careful not to hit bearing or
windings.
7. After disassembly, all .parts should be wiped
clean and visually inspected.
SUPPORT ROTOR
WITH HOIST AND
SLING TO AVOID
BENDING THROUGH
STUD
INSERT PRY BEHIND
BLOWER WHEEL THROUGH
AIR OUTLET OPENING
TURNNUTOUTTO
END
OF
GENERATOR
THROUGHBTUD
STRIKE WITH SOFT
HAWER WHILE
PRYING.
=.
~
,
d
FIGURE
39.
ROTOR REMOVAL
BRUSHLESS
EXCITER STATOR
I
FIGURE
38.
GENERATOR DISASSEMBLY
35
ASSEMBLY
9.
Torque down rotor-through-stud nut
55-60
ft. Ib
1.
2.
3.
4.
5.
6.
7.
8.
Clean and inspect all mating surfaces.
Coat mating area between generator bearing and
end bell bearing hole with a thin film of Molykote
or equal.
Install rotor-through-stud in engine crankshaft.
Install key
in
the crankshaft.
Slide rotor over through-stud and onto
crankshaft. Be careful not to let weight of rotor
rest on or bend the through-stud.
Install baffle ring.
tnstall stator through-studs in adapter.
Install stator and end bell. Torque nuts on
through-studs to
19
to
21
ft-lbs
(26
to
28
Nom).
MakeartalntheBl
kadlsplsccdthroughthegrommetinthe
bffk
ring
and
out
the
air
dirchargf!
openlng
in
the
adrptcr.
(75-81
Nom).
The rotor and stator are automati-
cally aligned because stator and bearing support
were tightened in step
8.
10. Tap end bell to align at horizontal and vertical
plane; use a lead hammer to relieve stresses on
components (recheck torque).
11.
Reconnect leads to preheater, centrifugal switch
and governor solenoid.
12.
Install lead
B1
on adjustable resistor,
R21.
.
.
Check
B1
lead to
see
that it
is
short and
is
kept away lrom the blower.
If
near-
rery
when Installing
a
new
stator
or
leads, cut
B1
lead
shorler
and
reinstail
the
connector.
13.
Install end bell cover.
36
.
PTO
ALTERNATORS
ALTERNATOR DESCRIPTION
The
15
kW
through
30
kW
alternators are four-pole,
revolving field, brushless exciter, 1800rpm modelsof
drip-proof construction. Alternator design includes
both single and three-phase,
60
hertz type alterna-
tors. The alternator rotor is fastened to the gear case
by the rotor through-stud which passes through the
rotor shaft, Figure
40.
The end bell and stator housing are attached by four
through-studs which pass through the stator
assembly to the gear
case
alternator adapter. The
brushless exciter stator mounts in the end bell while
the exciter rotor and its rotating rectifier assemblies
mount on the alternator rotor shaft. The shaft is
supported at both ends by lubricated ball bearings. A
centrifugal blower on the drive end of the alternator
draws air through the alternator for cooling.
The complete alternator includes
a
built-in exciter
and voltage regulator, mounting feet, lifting eye,
mounted gear box and splined driveshaft and control
box,
which includes voltmeter and a full output load
Plug-
Control
Box
The control box includes the voltage regulator,
voltmeter,
15
amp duplex receptacle with circuit
breaker, 50 amp welder receptacle with circuit
breakers, a full output load connector with load
circuit breakers, and
a
field circuit breaker. The load
circuit breakers can be used as an onoff switch.
Alternator power must feed into the farm electrical
system through an approved double throw load
transfer switch.
Gear
Box
The gear box and alternator adapter contain
two
helical gears supported by heavy duty ball bearings.
The bearings and gears are lubricated by the gear box
oil. The gear box requires 1.0-pint
(-47
litre) of SAE
90
EP
(extreme pressure) gear lubricant.
ORIGINAL EQUIPMENT
MANUFACTURERS PRODUCTS
Onan manufactures several versions of
YD
PTO
alternators which are sold nationally under other
brand names. The major difference
in
these units are
location
of
control components and the form
of
mounting hardware.
37
SPECIFICATIONS
SINGLE PHASE ALTERNATORS
b'
.
Starting
Watts
......................
Running. Watts..
....................
Volts
...............................
Phase..
............................
Hertz
..............................
Current
(Amperes).
.................
Power Factor
.......................
Wire
...............................
Brushless
..........................
Alternator
Speed
(Nominal)
.........
Tractor
Speed
(Nominal)
............
Minimum Horsepower Required
Driving Source
.................
Gear Box Oil Capacity, Pints
........
Gear Lubricant
.....................
Weight
.............................
15.OYD-3G
37.500
.
15,000
1201240
1
60
62.5
1
.o
4
Yes
1800
540
30
1.0
Pt
(0.47 litre)
SAE 90 EP
354 Ibs. (161 kg)
20.OYD-3G
52,000
20,000
1
201240
1
60
83.3.
1.0
4
Yes
1800
540
35
1
.O
Pt
(0.47 litre)
SA€ 90 EP
398
Ibs.
(181 kg)
THREE PHASE ALTERNATORS*
45
1.0
Pt
(0.47 litre)
SA€ 90 EP
438
Ibs.
(198 kg)
Starting Watts
..............................
Running
Watts
..............................
Volts..
.....................................
Phase
......................................
Hertz
......................................
Current (Amperes).
.........................
Power Factor.
..............................
Wire
.......................................
Brushless
..................................
Alternator Speed (Nominal)
.................
Tractor Speed (Nominal)
....................
Minimum Horsepower
..
Required, Driving
Source
.................................
Gear Box Oil Capacity, Pints
................
Recommended Gear Lubricant
..............
Weight
.....................................
.
20.0Y D-5D G
57,500
20,000
1201240
3
60
60.2
0.8
4
Yes
1800
540
35
1.0
Pt
(0.47
litre)
SAE 90 EP
423
Ibs.
(192 kg)
All
models
are
CSA
Certified.
'Delta wound, one phase center-tapped
to
deliver 120/240
volt,
single-phase
power in capacities
to
2J3
of
rated
%phase
kVA.
25.OYD-3G
62,500
25,000
120/240
1
60
104.2
1
.o
4
Yes
1800
540
25.OYD-5DG
70,000
25,000
120/240
3.
60
75.4
0.8
4
Yes
1800
540
45
1.0 Pt (0.47 litre)
SAE 90 EP
438
Ibs.
(198 kg)
30.0Y D-3G
80,000
30,000
1201240
1
60
125
1
.o
4
Yes
1800
.
540
.
55
1.0
Pt
(0.47 litre)
SAE 90 EP
483 Ibs. (219 kg)
30.OYD-5DG
95,000
30,000
120/240
.3
60
90.5
0.8
4
Yes
1800
540
55
1.0
Pt
(0.47 litre)
SAE 90 EP
512
Ibs.
(232
kg)
38
FIELD
EREAKEP
\
VOLTMETER RECEPTACLE
BREAKER
/
PTO
SHAFT
DRIVE
120
VOLT,
I5
AMP
240
VOLT.
50
AMP
CONTROL BOX CIRCUIT BREAKER
LIFTING EYE
ALTERNATOR
ALTERNATOR
STATOR
EXCITER STATOR
EXCITER ROTOR
ROTOR-THROUGH-STUD
TORQUE TO
55-60
FT.
LES
MOUNTING
FOOT
FIGURE
40.
YD
TRACTOR
DRIVE
ALTERNATOR
WIRING
CONNECTIONS,
15-25
kW
SINGLE PHASE ALTERNATORS
The most popular single phase connection is the
120/240combination. With this connection either 120
or 240 volts can be used alone or
at
the same time
(Figure 41).
Refer to page 8for wiring connections
of
30
kW
units
using the
UR
control.
EXCITER
WINDING
VOLTMETER
VOLTAGE REGULATOR
'
F;Gi?F
-'-
,e3
to.
1
LINE
I
CIRCUIT
c85
BREA
KE
R
&:
FIELD BREAKER
GI(
I
)
ALTERNATOR
?I
CBi
CB2
RECEPTACLE
1,,-q
POWER
CAB LE
RECEPTACLE
240
v.
RECEPTACLE
&
GROUND
r
FIGURE
41.120/240
VOLT,
SINGLE PHASE CONNECTION
THREE PHASE ALTERNATORS
Three phase alternators are connected
as
shown in
Figure 42. The three load wires are connected to T1,
T2 and T3. Single phase (240 volts) can be obtained
between any two three-phase terminals. Single phase
(120volts) can be obtained between T1 and TO or T2
and
TO.
TO is the grounded terminal for 120
volts.
..
EXCITER
WINDING
OUTPUT
LEADS
VOLTAGE REGULATOR
FIELD BREA
ALTERNATOR
T4
w
I20
v.
RECEPTACLE
.KER
POWER
CABLE
RECEPTACLE
240
V.
RECEPTACLE
FIGURE
42
THREE PHASE
240
VOLT
DELTA
CONNECTIONS
.
40
NOTE:
For
detailed
troubleshooting
information
refer
to
GENERATOR
and
CONTROL
TROUBLESHOOTING
procedures
and
tests.
NATURE
OF
TROUBLE POSSIBLE
CAUSE
Alternator Overheats
1.
Windings and parts covered
with dirt and oil.
2.
Air intake
is
restricted
or
incoming air too
hot.
3.
Overloaded.
1.
Alternator loose on base.
2.
Defective bearing.
1.
External short circuit on
2.
Incorrect PTO speed.
Noisy Alternator
Low
Voltage Output
of
Alternator line.
No
Voltage Output,
or
Voltage Builds Up But
Is
High, Low, Unstable, TROUBLESHOOTING, Page 5.
.
Trips Field Breaker. ..
u
Refer to GENERATOR
.
A
few simple checks and a proper troubleshooting
procedure can locate the probable source of trouble
and cut down troubleshooting time.
1.
Check all modifications, repairs, and
replacements performed since last satisfactory
operation of set to be sure that connection of
generator leads are correct.
A
loose wireconnec-
tion, overlooked when installing a replacement
part could cause problems. An incorrect connec-
tion, an opened circuit breaker, ora loose printed
circuit board are all potential malfunction areas to
be eliminated by a visual check.
2.
Unless absolutely sure that panel instrumentsare
accurate, use portable test meters for
troubleshooting.
3.
Visually inspect components on voltage
regulator. Look for dirt, dust, moisture and cracks
in the printed solder conductors. Burned
resistors, arcing tracks are all identifiable.
Do
not
mark on printed circuit boards with a pencil.
Graphite lines are conductive and can cause
short
circuits between components.
REMEDY
1.
Disassemble alternator
and clean.
2.
Clean alternator air intake
and outlet areas.
3.
Remove part
of
load.
1.
Tighten mounting bolts.
2.
Replace. Check alignment.
1.
Test alternator with line
wires disconnected.
2.
Readjust PTO speed to
540
to
600
rpm.
Refer to GENERATOR
TROUBLESHOOTING, Page
5.
TABLE
7.
TROUBLESHOOTING
41
SERVICE
AND MAINTENANCE
PERIODIC SERVICE AND INSPECTION
Follow a regularscheduleof inspection and servicing.
Make a good visual check before, while, and after
alternator is operating; look for loose or broken leads
and bad connections.
GEAR BOX LUBRICATION
Use only
SAE
90
EP
multi-purpose gear lubricant.
Drain the gear box after the first
100
hours of
operation and refill with fresh lubricant of, the
recommended grade. Repeat this procedure each
year thereafter,
or
every
250
hours of operation,
whichever occurs first. Maintain the proper oil level
between changes.
Overfilling
will
causefoaming,
which
can
lead
Ezx
to
an
oil
kak.
CAUTION
Remove oil fill plug at top of thecaseand oil level plug
from the face of the gear case, Figure
43.
Fill
case
until oil flows from the oil level plug hole. Gear box
holds
1
pint
(0.47
litre)
U.S.
measure. Replace both
plugs.
PTO SHAFT LUBRICATION
Grease the universal joints
and
telescoping shafts
on
the
PTO
shaft at least every25 operating hours. Under
adverse conditions, grease the joints as required,
possibly every
4
to
8
hours.
WARNING
Never
operate
the
alternator
with
the
protec-
=
tive
guards
removed
from
the
PTO
shaft
Per-
mal
injury or
death
may
othemise
result.
BEARINGS
The ball-type bearing on the cover end
is
double
sealed and lubricated for life.
If
this bearing becomes
noisy, worn, or otherwise defective, replace it.
Re-
move the old bearing with a gear puller and drive or
press new ones into place. The bearing on the gear
box end is lubricated by the gear box lubricant
(SAE
90
EP). For disassembly and repair see Alternator
Repair section on page
47-
'
*
(PTO
GUARD
REMOVED)
FIGURE
43.
GEAR
BOX
LUBRICATION
'42
.
a’
.
I
TWO
BEARING
ALTERNATORS
GENERAL
Onan
YDtwo
bearing alternators
5.0
through
20.0
kW
are 50 and
60
hertz units designed for belt and pulley
or direct coupling to a separate prime mover.
Acentrifugal bloweron the frontend of the rotorshaft
circulates the alternator cooling air. The air
is
drawn
in
through the end bell cover, over the rotor, and
discharged through an outlet at the blower end,
Fig-
ure
4.4.
A
ball bearing at each end supports the rotor shaft.
The end bell and stator housing are attached by four-
through-studs which pass through the stator
assembly. The brushless exciter stator mounts in the
end bell while the exciter rotor and its rotating
rectifier assemblies mount on the rotor shaft.
VOLTAGE
REGULATOR
The line voltage regulator
is
an all solid state device.
Basic components of the voltage regulator are:
Printed circuit board
Voltage reference transformer T21
0
Commutating reactor CMR21
Field circuit breaker
Voltage adjust rheostat (optional)
Figure
45
shows the above components in a typical
control on standard units.
/FIELD
STATOR,
BREAKER
m\
I
CONTROL
JUNCTION
BOX
1-
---
ASSEMBLIES
ROTO
R-SHAFT
TORQUE
TO
130
TO
STATOR-THROUGH-S
I
1
\
mu11
.
END
BELL
TORQUE
TO
19-21
FT.
LBS
ROTOR
(S28
Wm)
150
FT.
LBS
TUD
flGURE
44.
GENERATOR
(CUTAWAY
VIEW)
43
I
REGULATOR MOUNTING
PANEL
FIELD
CIRCUIT
BREAKER
I
I
I
I
CYRZI-2
I
7821-1
I
-
I
t
I
I
I
CURZI-3
I
7821-2
I
-
I
I
I
1
CURZI-4
I
VR2l-9
I
-
I
I
I
CBZI-2
VRZ
1-1
0
TBZ
I
-F
1
VR21-8
yR2
1-7
14
CONTROL
BOX
The control box (on top
of
the alternator) contains the
voltage regulator and the lowerportion of the junction
box
for
making alternator to load line connections.
The generator output leads are accessible by remov-
ing the control box cover,
I
VRPI-V4
COY.
I
VPl-VI
1
15
1
I
1
15
VR21-1
yR21-2
.
FIGURE
45.
VOLTAGE
REGULATOR
ASSEMBLY
OPTIONAL
SWITCHBOARDS
Switchboards (Figure
46)
are optional equipment
which can be purchased at added cost. They contain
a voltmeter; ammeters, line circuit breakers and
marked terminals. The switchboard is used to check
alternator voltage, load current and.voltage regula-
tion with a varying load.
When ordering parts for switchboards, obtain part
numbers and description
of
part from the wiring dia-
gram supplied with the switchboard.
..
c
AC VOLTMETER
I
KNOCK
OUTS
SINGLE POLE
LINE CIRCUIT
BREAKERS
FIGURE
46.
TYPICAL
WALL
MOUNTING
"SB"
SWITCH-;
BOARD
-
3
PHASE,
120120a
VOLTS
44
SPECIFICATIONS
MODEL NO.
AND
KW
RATING
6.0-3CSl
7.5-3cs/
TWO
BEARING ALTERNATORS
ELECTRICAL DETAILS GENERAL UTILITY
RATING
Frequency
kVA
Amps
Weigh€
(Approx.)
In
Hertz
Phase Wires Watts at
PF
240V
Lbs.
kg
60
1
4
6000
6.0
@
1.0
25.0
235
106.6
60
1
4
7500
7.5
@
1.0
31 -3
259
11
7.5
NO=
All units are two-bearing alternatorsdesigned for clockwise mtation with belt andpulley drive or direct drive coupled to a
separate prime mover- The direction of rotation is clockwise only; it is determined when facing the drive shaft end. The
60
hertz
units operate at
1800
rpm while the 50 hertz units operate at
1500
rpm.
NOTE:
The 3CSland 53CSlmodelsare
1201240
voltsinglephase units. The lSSland518Slmodels are threephase broadrange
reconnectible units.
See Figure
19,
page
20,
for voltage codes, wiring diagram, and connection diagrams.
'
45
NOTE:
For
detailed
troubleshooting
information
refer
to
GENERATOR
and
CONTROL TROUBLESHOOTING
procedures
and
tests.
-I
A
few simple checks and a proper troubleshooting
procedure can locate the probable source of trouble
and cut down troubleshooting time.
1.
Check all modifications, repairs, replacements
performed since last satisfactory operation
of
set
to be sure that connection of generator leads are
correct.
A
loose
wire connection, overlooked
when installing a replacement part could cause
problems. An incorrect connection, an opened
circuit breaker, or
a
loose printed circuit board
are all potential malfunction areas to be
eliminated by a visual check.
1.
Speed
IGW
because of
loose, slipping
belts.
2.
External short circuit on
line. wires disconnected.
3.
Open circuit
of
shunt field
winding.
4.
Short circuit of winding
in
the field
or
armature.
1.
Adjust belt tension.
2.
Test alternator with
line
3.
Make proper connections.
4.
Refer
to
GENERATOR
.
TROUBLESHOOTING, Page
5.
2.
Unless absolutely sure that panel instrumentsare
accurate, use portable test meters for
troubleshooting.
3.
Visually inspect components on voltage
regulator. Look for dirt, dust, or moisture and
cracks in the printed solder conductors. Burned
resistors, arcing tracks are all identifiable.
Do
not
mark on printed circuit boards with a pencil.
Graphite lines are conductive and can cause
short circuits between components.
c
TABLE
7.
TROUBLESffOOTING:
Low
Voltage Output
of Alternator
.
46
ALTERNATOR REPAIR
GENERAL
Disassembly and reassembly
of
.the
PTO
and
two
2. Remove gear case drain plug and allow oil to
drain, Figure
48.
Use
a
new
gasket when replacing
gear
case
cover.
bearing akernators are nearly identical. The
difference involves the drive end and the controls.
Use the appropriate Parts Catalog and Wiring
Diagrams as aids in reassembling the control box
hardwareand the alternatoroutput and control leads.
The following items require disconnecting and remo-
val before disassembly of gear case and alternator:
-
-
.
Disconnect engine PTO shaft.
Remove control box cover.
0
Disconnect alternator output leads from control
Disconnect exciter leads F1 and
F2
at printed
Remove control box from alternator.
components.
circuit board.
GEAR CASE
DISASSEMBLY
The gear case cover is drained of oil and removed
from the unit for two purposes: (a) gear, bearing, or
shaft replacement; and (b) to provide a
flat
end for
supporting the alternator during disassembly and
reassembly.
1.
Remove PTO guard by loosening three 5/16
x
1/2-inch locking screws, Figure
47.
FIGURE
48.
DRAINING GEAR
CASE
..
.
RETAINING RING
IR
OUTLET
GRILL
PTO
SHAFT
TUMBLING
ROD
PLATE
GUARD
..
FIGURE
47.
GEAR
CASE ASSEMBLY
47
f
3.
Removesix5/16x l-inch capscrewsandWo5/16
-
l-l&inch cap screws and gear case plate, Fig-
ure
49.
5.
Block
up gear case plate as shown in Figure
51
and tap
PTO
shaft out of plate.
To
assure
a
good
seal
always
we
a
new
gear
case
gasket
when gear
case
plate
Is
assembled.
FIGURE
49.
GEAR CASE
PIATE
REMOVED
4.
If necessary, remove seal and snap ring from
around
input
shaft, Figure
50.
Oldseal
mutt
be
replaced
with
a
new sealwhen
reassembled
A
FIGURE
51.
REMOVAL OF
PTO
SHAFT
FROM
GEAR
CASE
PLATE
6. Remove snap ring and tap bearing through gear
box
plate, Figure
52
FIGURE
50.
INPUT SHAFT SEAL AND SNAP
FIGURE
52
GEAR
PLATE
BEARING
REMOVAL
RING REMOVAL
48
.
The drive gear and innerend bearing are pressed on the Input shaft
and
held
In
place
by
a
key and
a
retaining ring, Flgure
53.
Use
a
suitable press when
it
is
necessary
to
replace
the
bearing, gear
or
shaft.
FIGURE
53.
INSTALLING SNAP RING BEHIND
DRIVE GEAR BEARING
ALTERNATOR
DISASSEMBLY
The alternator disassembly and reassembly
is
safer
and easier
with
thealternator
in
the vertical position
as
shown
in
following sequence of illustrations.
Alternator components are heavy,
so
use
a hoist
and
rope sling and stator tongs for handling and separat-
ing
the
components, Figure
54.
On
two
bearlng alternators, remove drlve end bearlng plate and
shaft
key
before
upending the unit
for
dlsassembty.
1.
2.
3.
Usea hoist and ropesling to raise theend
bell
end
up
to
a
vertical position.
Support unit
on
drive end
and
use special blocks
to protect drive shaft.
This
step isn't necessary on
PTO
units
if
the
gear case cover and shaft are
removed first.
Remove four
nuts
from rotor-through-studs,
Figure
55.
'
n
FIGURE
55.
END BELL REMOVAL
BLOWER
,
KEY
ROTOR
BRUSHLESS
A'REA
FLE
STATOR
EXCITER
f
I
ROTOR
THROUGH-STUD
STATOR
/
THROUGH-STUD
COVER
FIGURE
54.
ALTERNATOR DISASSEMBLY
49
4.
Remove end bell by tapping upward around joint
.
and separating
it
from stator assembly, Figure
56.
FIGURE
56.
FREEING END BELL
FROM
STATOR
5.
Remove four stator through-studs with vise grip .
pliers as shown in Figure
57.
Reinstall two studs
.
during reassembly for aligning and guiding the
'
.
stator over the rotor.
FIGURE
58.
STATOR
HANDLING TONGS
A
pair
of
tongs is the most suitable device'for han-
dling stators, Figure
58.
The tongs shown were made from one inch steel bar.
stock. The tongs should be a suitable size for han-
dling several different size stators.
FIGURE
57.
STATOR
THROUGH-STUD BOLT REMOVAL
50
6.
Using a safe lifting device, stator handling tongs,
or chain and lift hooks,
lift
stator assembly from
gear
case
adapter.
If
necessary,
lift
unit
off
bench
about one inch and tap adapter housing with a
soft faced hammer to free stator from adapter,
Figure
59.
.
FIGURE
59.
STATOR REMOVAL
DO
not
set
stator
down
on
open
end,
top
or
bottom,
because
stator weight
can
damage
the
windings.
8.
Remove air baffle by loosening four locking
screws, Figure
61.
7.
While stator is stiil on lift tongs or hooks, revolve
stator to horizontal position and set it down on its
side, Figure
60.
FIGURE
61.
AIR BAFFLE REMOVAL
FIGURE
60.
REVOLVING STATOR FOR REPAIRS
51
c
9.
10.
A
FIGURE
62
ROTOR
HANDLING
SLING
A
rope sling is the most suitable device for han-
dling rotors, Figure
62.
Remove rotor and fan .by using a soft-faced
hammer to tap on the adapter while holding the
rotor assembly about one inch above bench with
a hoist and rope sling, Figure
63.
Uie
care
to prevent damage to the fan
Iz3
blades. Broken bladeswill
throw
the fan
out
of
balance and
reduce
the air
flow
rate.
If it
is
necessary to replace a damaged fan, sup-
port rotor assembly horizontally and remove fan
from rotor with a gear puller. Use the holes
pro-
vided in fan to attach gear puller tongs.
CAUT~ON
FIGURE
63.
ROTOR
AND
FAN
REMOVAL
Use care to prevent damage
to
thefan blades.
Broken blades will throw the fan
out
of
balance and reduce the air flow rate.
11.
Hold
rotor in
a
suitable clamp and loosen nut on
rotor-through-stud bolt as shown in Figure
64.
FIGURE
64.
ROTOR
THROUGH-STUD
NUT
REMOVAL
52
0455
FIGURE
65.
ROTOR
BEARING REMOVAL
12.
If
required, remove bearing with agear pullerand
accessory crutch
(if
available)
from rotor through
stud, Figure
65.
13.
Clamp alternator rotor in
a
fixed vertical or hori-
zontal position to remove or install the rotor
lock
nut, Figure
66.
Lock nut
is
torqued
to
130-150
ft.
Ib. (176-203
Nom).
FIGURE
66.EXCllER
ROTOR
LOCKING NUT REMOVAL.
53
14.
15.
If bearing, shaft, or oil seal replacement is
re-
quired, hold gear case upright and tap drive pin-
ion and shaft through gear case, Figure
67.
16.
Remove snap ring from bearing on drive pinion
shaft, Figure
68.
17.
Press
bearing from drive pinion shaft if bearing
(Not Illustrated)-With vise grips, remove rotor
through-stud from drive pinion shaft. replacement is required,
FIGURE
67.
REMOVING DRIVE PINION
SHAFT
FROM
GEAR
CASE
FIGURE
68.
DRIVE
PINION
SHAFT
BEARING
i
SNAP RING
REMOVAL
Use care to
prevent
damage
to
the
fan
blades.
Broken
fan
blades
will
throw
the
6. Install
two
stator throughstuds in adapter for
aligning stator assembly over rotor during
assembly.
ALTERNATOR ASSEMBLY
Assemble alternator components in reverse order
follow:
from disassembly using additional instructions that
fan
out
of
balance
and reduce
the
air
flow
rate.
1.
Clean and inspect
all
mating surfaces.
2. Coat mating area between alternator bearing and
end bell bearing hole with a thin film of Molykote
or equal.
3.
Install rotor-through-stud in drive pinion
shaft,
if
it
was removed.
4.
Install rotor and fan assembly
on
adapter. Guide
raised line on the fan body casting indicates the
location of key slot inside. The drive shaft and key
can be seen through the air outlet in the adapter.
5.
If they were removed, install exciter rotor and
shaft bearing.
Hold
fan with wooden stick and
torque shaft nut against exciter rotor 130to
15Oft.
Ibs. (176 to 203 Nom).
7.
Install baffle ring.
8. Install remaining two stator throughstuds in
adapter.
9.
Install stator and end. bell. Torque nuts
on
through-studs to 19 to 21 ft-lbs
(26
to 28 Nom).
Ib.
(75-81
Nom).
lnsta’l
mounting
feet
and
control
box-
l2
Connect
alternator
Output and
control
leads
according to appropriate wiring diagram.
13. Replace end bell cover.
14.
Replace control box cover.
key
‘lot
in
fan
Onto
key
in
drive
pinion
shaft.
A
10.
Torque down rotor-through-stud nut to
55-60
ft.
54
CONTROL
SYSTEMS
GENERAL
YD
generator sets
use
several
forms
of control boxes
and panels as shown
in
Figures
69
through
72.
Instrumentation and control functions vary because
of set design, different needs of each installation, and
optional equipment ordered
by
the customer.
*
For description
and
troubleshooting information on
the
30
kW
SK
engine
DC
controls, see Section
8Aof
Master Service Manual
900-0218.
FIELD
VOLTAGE ADJUST
BREcKER
CIRCUIT
RHEOSTAT,
RESET BUTTONS.
\
\
S
\
METER
FAULT
LAMP
FIGURE
69.
TYPICAL AIR-COOLED’AND MARINE
SET CONTROL PANEL
CONTROL PANEL COMPONENTS
The following
is
a
brief
description
of
typical controls
and
instruments
on the face
of
the
panels; these may
vary according to the customer purchase order.
Start-Stop Switch: Starts and stops the unit locally.
Battery Charge Rate
DC
Ammeter.
Indicates the
battery charging current.
Field Circuit Breaker: Provides generator exciter and
regulator protection from overheating
in
the
event
of
.
AC
VOLTMETER
LINE
CIRCUIT
BREAKER
PHASE
SELECTOR
WIT-
B218
AC AMMETERS
*
FIGURE
70.
CONTROL PANEL AND OUTPUT
BOX
AIR-COOLED
SET
ONLY
certain failure modes
of
the generator, exciter, and
voltage regulator.
Pre-Heat Switch: Provides pre-heat conttol for
manifold heater and glow plugs for cold diesel engine
starting.
Oil
Pressure
Gauge: Indicates pressure
of
lubricating
oil
in
engine (wired to
a
sensor unit located on the
engine).
ACVoltmeter: Indicates
ACgeneratoroutputvoltage.
Voltmeter Phase Selector Switch: Selects the phases
of
the generator output to be measured
by
the
AC
voltmeter.
Voltage Adjust Rheostat: Provides approximately
plus
or
minus
5
percent adjustment
of
the
rated
output voltage.
CC
AC
.AMMETERS
WATER TEMPERATURE
GAU
EMOTE HEATER
WITCH
UN-STOP
SWITCH
FIGURE
71.
TYPlCAL
RAMATOR-COOLED
SET
CONTROL
PANEL
Cranking
Limiter: Some systems have a thermally
activated device that limitscranking
45
to 90seconds
depending on ambient temperature.
A
red pushbut-
ton popsout and cannot be reset until one minute
has
elapsed. Other solid state systems
(DTA)
limit crank-
Ing to
45-75
seconds before energizing a fault relay.
The relay stops the cranking function and turns on a
red Overcrank
lamp.
Running Time Metec Registers the total number of
hours,
to
I/lOth that the unit has run. Use
it
to keep a
record for periodic servicing. Time is accumulative;
meter cannot be reset.
Frequency Meter: Indicates the frequency of the
generator output in hertz.
It
can be used to check
engine speed. (Each hertz equals
30
rpm.)
Wzrning Lights: Indicator lights are used on some
controls to give warning
of:
56
set
failed to start
Overspeed
Low oil pressure
Pre
low
oil pressure
Low
engine temperature
High engine temperature
Pre high engine temperature
Overcrank
Start switch in
Off
position
Reset pushbuttons orswitches permit restarting after
,trouble
is
corrected.
.)
Line Circuit Breaker: Protects generator from line
overloads.
Water Temperature Gauge: Indicates temperature of
circulating coolant in engine. (Wired to a sensor unit
located on the engine.)
/-\
\-/
RESEi
START PRIME WPTESl
STOP
REMOTE
FIELD
CONTROL REMOTE
BREAKER BREAKER BREAKER
@
@
@-
~~
MDTA SERIES
8
0
m
0
0
3
PHASE-
-
VOLTAGE
ADJUST
1
PHASE
RESET
START
PRIME LAMPTEST
a
REMOTE
@@@
FlELLl
CONTROL
REMOTE
RUN
PRE HI ENG TEMP
PRE
LO
OIL
PRES
LO
ENG TEMP
HI
ENG TEMP
OVERSPEED
OVERCRANK
LO
OIL
PRES
SWITCH
OFF
DTA SERIES
FIGURE
72
TYPICAL
CONTROL PANELS, DTA/MDTA
I
57
ENGINE CONTROL SYST.EM OPERATION
Dependable, trouble-free operation of the control
system should be the major concern of any compe-
tent generator set service personnel. Service person-
nel must thoroughly understand how the controls
operate, know how to check for troubles, and know
how to make the proper adjustments, replacements,
or repairs in a reasonable amount of time.
The circuitry, control components, and operating
cycles for air-cooled and marine generator sets are
similar, however the gasoline and diesel-powered
sets are different enough to be described separately.
Prior
to
starting the generator set, check the fuel
supply, engine oil level, and all battery connections
for loose or broken wires. If an automatic demand
control is in use, check for correct connections.
GASOLINE POWERED
SETS
The DC start and run circuits are supplied by the
12-volt battery and charge winding of the generator.
The control circuits are completed by returning to
ground (negative post of battery).
Figure 73shows a typical wiring diagram for gasoline
powered sets described in the following Starting,
.Start-Disconnect and Stopping sequences. Relay
contact references normally open (NO) and normally
closed (NC) referto position of contacts with the unit
at rest (not energized).
Starting
Sequence
The Start-Stop switch
is
pressed and held at Start
position until the engine starts and runs.
Do
not hold
mltch
longer
than
30
seconds
Ex
during any
attempt
to
stah
Longer
periods
my harm
the
starter
motor
and
discharge battery
needlettly.
1.
The start circuit is completed by Start-Stop
switch S11 at the 'Start position. This action ener-
gizes Start Relay K11 via NCcontacts of the Start-
Disconnect Ignition Relay K12.
2.
Start Relay
K11
has
two
sets
of
NO
contacts per-
forming the following functions when energized:
a. One set connects battery
B+
to: primer sole-
noid K3, thermal choke S3, and starter motor
shift solenoid
B1.
b. The other set connects
B+
to: the breaker
point assembly
S3
(via high temperature
switch S2 and
NC
contacts of optional Emer-
gency Relay 'K14), thermal choke heater S3,
and other fuel control components.
CAUT,ON
'If
K14 should energize and stop the engine, a brief period is
required for the relay's heater to cool before the relay con-
tacts reset to the de-energlzed position for starting again.
Start-Disconnect Sequence
When engine speed reaches
900
rpm, centrifugal
switch
S1
closes. This connects
B+
to the Start-
Disconnect Relay K12 via resistor
R1
1. The
NC
con-
tacts of K12 now opens the K11 start circuit. The
NO
contacts of K12 close to connect
B+
(via K14 con-
tacts) to the ignition circuit and fuel control .com-
ponents.
#
Stopping Sequence
Holding
S11
in Stop position de-energizes K12 which
opens
B+
circuit to the ignition system and fuel con-
trol components.
DIESEL
POWERED
SETS
The
DC
start and run circuits are supplied by the
12-volt battery, and by the charge winding of the
generator. The control circuits are completed by
grounding to the negative pole of the battery.
Do
not apply overvoltage
to
the starting cir-
.E3
cuit at any time. Overvoltage will destroy the
glow
plugs
and air heater in
two
to
three
seconds.
If it becomes
necessary
to
use
an additioml
source
of
power to
star!
the
unit-
use
a
12-volt
battery
connected
in
parallel
with
the
starting
bancrier.
CAUTION
The following starting, startdisconnect and stopping
sequences are referenced to the typical control
schematic in Figure
74.
Test reference to relay contacts normally open (NO)
and normally closed (NC) refer to position
of
con-
tacts with the unit at rest (not energized).
Starting Sequence
1.
2.
For cold engine starting, the Pre-Heat Switch
S12
is held in the Heat position for 30 seconds if
ambient temperature is above
55OF
(43OC);
60
seconds if below
55OF.
This action energizes the
Manifold Heater Relay K13 which connects bat-
tery
B+
to the manifold and glow plug heaters
After proper pre-heat time,
512
is
released and
start circuit energized (Step 2).
The start circuit is completed by Start-Stop
Switch
SI
1
at the Start position. This action ener-
gizes Start Relay K11 via
NC
contacts .of relay
K12. Relay K13 is also energized by S11 at Start.
c
HRl-5.
.I
58
I
TI IC0 IL-IGNITION
I
I
621
I
GENERAlOR
RZI
lRED!3oR
ASSI
I
VRZZ
lREGULATOR ASSY-VOLTAGE
VR23
I
REGULATOR
ASSY
-VOLTAGE
I
W/O
V
ADJ)4.-CIZ.+S~-OWO.
Q.-w
I
WV
ADJl-O~-O4,-O7.~-ll-l22d-.lr
I
I
I
J
CRII
IRECTIFIER
a
LEAD
ASSY
FI
INSE-IO
AMP
I
KII
IRELAY-START
SOLWID
'
(02
IRELAV#LEID
IdsV
K14
IRELAY-EYERGEUCY (LOP1
I
I
1-
I
FIGURE
73.
TYPICAL GASOLINE ENGINE CONTROL SCHEMATIC
~~~
FIGURE
74.
TYPICAL DIESEL ENGINE CONTROL SCHEMATIC
59
Umlt
cranking
15
to
20reconds
to
con-
5ewe battery
and
prevent possible
harm
to
the
starter
motor
Bl.
3.
Start Relay K11 has
two
sets of
NO
contacts per-
forming the following functions when energized:
a. One set connects battery
B+
to the starter
motor shift solenoid B1.
b.
The other set connects
B+
to the fuel solenoid
K1 and optional fuel pump El via
NC
contacts
of optional Emergency Relay 'K14.
'If
K14
should energize
and
stop
the
engine,
a
brief
period
Is
required
for
the
relay's
heater
to
eo01
before
the
relay
contacts
reset
to
the
de-energized
position
for
starting
again.
Start-Disconnect Sequence
When engine speed reaches
900
rpm, centrifugal
switch S1 closes. This connects B+ to the Start-
Disconnect Relay K12 via resistor
Rll.
The
NC
con-
tacts of K12 open the cranking circuit. The
NO
con-
tacts of K12close to keep B+ (via K14contacts)
to
the
fuel solenoid K1 and the fuel pump El.
Stopping
Sequence
Holding SI1
in
Stop position de-energizes K12 which
opens B+ circuit to the fuel solenoid and pump.
The
fuel solenoid shaft forces the injection pump control
arm to the no-fuel position. The engine stops from
lack of fuel.
a
,
60
Redistribution or publication of this document, 
by any means, is strictly prohibited.
MOTE:
ULES
OTHERWISE
1I1)TED.
ALL
COIPONEWTS ARE
SHOW
IN
THE
~M-EW~OZED
msiiiow.
.
Mll
CAUEE
-
OIL
PRESS.
112
.EIUEE
-
WATER
TEMP
113
AIIETER
-
CHARGE
5-0-5
,
111
RESISTW
-
3.0HT.
101
$11
.
SWITCH
-
PANEL
LIGHT
S12
SllTCH
-
SELECTOR
SW
SWITCH
-
UNI-
1111
BLOCK
-
TERMINAL
I.
mi
BLOCK
-
TERIIMAL
WM
USED
~~
FIGURE
75.
TYPICAL CONTROL SCHEMATIC, RADIATOR-COOLED J-SERIES DIESEL ENGINE
61
RADIATOR-COOLED DIESEL SETS
The control components on the water-cooled, diesel
sets are similar to the air-cooled and marine sets, but
the circuitry and operating cycles are different. The
solid-state control used on the DTNMDTA Series is
described separately.
The DC start and run circuits are supplied by the
12-volt battery, and by the battery charging system.
Do
not apply overvoltage
to
the starting
cir-
cult at any time. Overvoltage will destroy the
glow plugs and air heater In
two
to
three
seconds.
If
it becomes
necessary
to
use an additional
source
of
power to
start
the unlt-
use
a 12-volt battery connected In parallel with the
starting
batteries.
Prior to starting, check the fuel supply, engine oil
level, and all battery connections for loose or broken
wires. If an automatic demand control is
in
use, check
for correct connections and make sure the selector
switch is
in
Remote position.
Figure 75 shows a typical schematic diagram for
radiator cooled diesel sets described in the following
Starting, Start-Disconnect and Stopping sequences.
Starting Sequence
The following sequence of electrical functions occur
during the starting operation. Relay contact text ref-
erences normally open (NO) and normally closed
(NC) refer to position of contacts with the unit at rest
(not energized). .
With S12 in
the
Remote position, the operator can
start the set from a remote location,
or
by an auto-
matic demand control.
In
this position only is engine
preheating controlled automatically by 20 second
Time Delay Relay K17. Relay K17 is energized by
B+
connected through the remote switch, and through
S12 in the Remote position.
Manual starting at the set involves the following
sequence
of
electrical and mechanical functions:
1.
,
2.
For
cold engine starting, the Pre-Heat Switch S13
is held
in
the Heat position for 30seconds if below
55°F
(13OC); 60 seconds if below 55OF. This
action energizes the Heater Relay K1 which con-
nects
B+
to the manifold and glow plug heaters
HR1-5. After proper pre-heattime, Sl3is released
and the start circuit energized (Step 2).
The start circuit is completed when the selector
switch is moved
to
the Run position. This action
energizes Fuel Relay K11 via normally closed
contacts K14 and K15 (Cranking Limiter and
Emergency Shutdown Relays). When K11 con-
tacts close,
B+
energizes the following com-
ponents.
Oil pressure meter M11.
Water temperature meter M12.
Fuel solenoid K3.
Optional water solenoid K2 and fuel pump E3.
Heater Relay K1 via NC contacts of Si3 and
K13 (Start-Disconnect Relay).
Starter RelayK16via K13and S12. (Relay K16
connects B+ to the B1 starter solenoid and
Cranking Limiter Relay K14.)
Start-Disconnect Sequence
When engine reaches about 900 rpm, centrifugal
switch S4 closes and energizes relays K12 and K13
(Oil Pressure and Start-Disconnect). The NC con-
tacts of K13 opens the K16 Starter Relay circuit and
starter.solenoid BI.
Stopping Sequence
Positioning selector switch S12 to Stop position dis-
connects
B+
voltage from the control circuits; there-
by de-energizing all control components required to
operate the engine
in
either Run
or
Remote con-
dition.
Emergency Shutdown
Emergency Shutdown Relay K15
is
controlled by any
one of three switches: S1 low oil pressure, S2 high
water temperature, and S3 overspeed. Contacts of
K15 control two circuits: one normally closed set
of
K15 contacts controls the fuel solenoid relay coil to
shut
off
the fuel supply to the engine; the other nor-
mallyopensetclosestolightthe pilot lightandsetoff
the emergency alarm whenever the emergency shut-
down relay energizes.
CONTROL
OPERATION
(DTNMDTA
SERIES)
Figures 76and 77show the PC board and DCcontrol'
schematics for the solid state control. Relay contact
text references normally open
(NO)
and normally
closed (NC) refer to position of contacts with the unit
at rest (not energized).
Starting Sequence
The start circuit is completed by switch S10
in
the.
Start position. This action energizes On/Off Relay
K2
which puts B+atStopSolenoid KSand Fuel Pump
El'
(via contacts K2, K1 and J1-4). As K5 energizes, its
NC
contacts open and allow the Starter Pilot Relay K4
to
energize (via contacts K2,
K1,
K3, J1-6, K6, P1-16
and K5 auxiliary coil to ground). The K4 contacts
connect
B+
to the Starter Motor Solenoid K and
cranking begins.
.62
.'
.
300-1696
ENGINE MONITOR
PCB
It
I
I
FIGURE
76.
DC CONTROL
SCHEMATIC
DTNMDTA (OPTIONAL METERING)
63
Start-Disconnect Sequence
When cranking begins, the solid-state crank-limiter
timer is activated. If engine does not start
in
45-75
seconds, Fault Relay
K1
energizes and cranking
stops. Engine start
is
determined when voltage out-
put at auxiliary terminal of the belt driven alternator
energizes the Start-Disconnect Relay
K3.
Relay
K3
stops the timer sequence and opens the cranking
circuit.
Stopping Sequence
'
Placing switch
S10
in
Stop position de-energizes
relay
K2
which opens
B+
circuit
to
the Stop Solenoid
and Fuel Pump. The Stop Solenoid connecting rod
moves the
injection
pump control tothe no-fuel posi-
tion. The engine stops from lack
of
fuel.
Emergency Shutdown
Fault Relay
K1
can be energized by any of several
sensors as follows:
S3
low oil pressure switch,
S5
high engine temperature switch,
S7
overspeed
switch,
OC
(overcrank) Limiter.
When
K1
is energized, a NC set of contacts open
B+
to the Stop Solenoid and Fuel Pump, and another set
closes to connect
B+
to an optional fault alarm. The
engine sensor causing the fault triggers a transistor
circuitthat lights up theappropriate fault lamp on the
control panel. Theengine cannot be started until fault
condition is corrected and the Reset Switch
S12
pressed.
The
Low
Oil Pressure Delay circuit is not .actuated
until the Start-Disconnect Relay is energized. The
circuit allows
a
delay of
7.5
to
12.5
seconds
before
LOPshutdown and prealarm are functional. Follow-
ing
this initial delay, both the
LOP
shutdown and
pre-alann functions
are
immectiate.
.
64
.
R29.34 2
AZO-26
7
R7.9.11.13.15. 7
17.19
R35
I
Rlb.E.IO.
12.14
15
16.18.27.28.32
(111-17
7
P4.5.7-IO.I8
7
(11-3
3
K3
1
K2
I
KI
I
11-3
3
CR12
I
CR13-
I
1.B-28.32
27
CA29
I
C12.9
2
CI
I
I
c8.10
2
$1-7
7
REF.Dp.
111
1136
1.
I
UI-2
782
TBI
tSO.33
e
~ISTOII
(ID~,I/N,W
TRUSISTM-
SIONALIYPS
653OEOl.4
DIODE-400V
14041
(-OI.-oL)
SILKSCREEN-
PC
-0
(-05)
SLISQIEEH-
PC
WARD
(-02)
SOLDER-BAR
IGPROGIMA8LE TIMER
TEWINAL
BLOCK4
PLC
1-01.42)
TEWINAL BLOCK-12 PLC
RESISTOR
(IOOK.1/21.5Z)
RESlSTOR
(47K,IL?N,55)
RESISTOR
(lOO.l/ZW.%)
RESISTOR
(6EO,l/ZW.%)
RESISTOR
(Z704~,5%)(-02)
RESlSlOR
(lOK.lL?W.S%)
TRANSISTORSIMIL
(UPS
6533)
-1.5%)
TRANSISTORSIMIL (UPS 6530)
TmsisrnR
(92W45A)
REUY-MIN
OPDl
REUY-SPST
REUV-TPDT
PUIGCMHECTOR
OIODE4OOY
(IR6054)
OIOOE-4OOY
(404)
DIODE-
4OOV
14D41(-01,-03)
CIPACITOR-TANT 147YFO.20V)
WACITOR
LO22
YFD.4OOV)
CAPACITOR
(.ism.
I
oov)
DASH
NO.
NOTE
1.
USE
CR29
FOR
-01
8-03,
USE
R25
FOR
-02
-.-
ma
--
_-
-..I--
FIGURE
77.
ENGINE MONITOR PCB SCHEMATIC
300.1896
(DTNMDTA)
65
a
a
a
W
9
a
W
z
f
6
a
3
0
E
b
w
66
The data in this section is divided into three flow
charts, and information on troubleshooting the
DTA/MDTA
solid-state control (page
a).
The flow
charts consist of:
A.
Engine does not crank.
B.
Engine cranks but does not start.
C.
Engine starts but stops when start switch is
Before starting a troubleshooting procedure, make a
few simple checks that may expose the problem and
cut down on troubleshooting time.
Check all modifications, repairs, replacements
performed since last satisfactoryoperation of set.
A
loose wire connection overlooked when instal-
ling a replacement part could cause problems. An
incorrect connection, an opened switch or circuit
breaker, or a loose plug-in are all potential prob-
lems that can be eliminated by a visual check.
Unless absolutely sure that panel instruments are
accurate, use portable test meters for trouble-
shooting.
released.
-
Check engine oil level. If
OK,
reset relay. Check oil
pressure switch
S4
and related wiring.
’
Is
LOP
emergency relay K14 tripped?
To
troubleshoot a problem, start at the upper-left
corner of chartand answerall questions eitherYESor
NO.
Followthe chart until the problem is found,
per-
forming referenced Control Component Checkout
procedures on page
70.
Refer to typical wiring dia-
grams
in
Figures 78 and 79for locating control com-
ponent leads, terminals and other check points.
Check for correct voltage at terminal blocks as shown
below. Measure voltage between terminal and
ground, or as indicated.
TBll-B+.
............................................
12
VDC
TB11-1
............................................
GROUND
TBll-2
....................................
l2VDC RUNNING
TBll-3
....................................
l2VDC STOPPED
TB11-H
....................................
l2VDC STOPPED
-12-4
....................................
l2VDC RUNNING
TB12-5
...................................
-12
VDC RUNNING
1612-6
..................
0-VDC STOPPED, l2VDC RUNNING
TB12-7
.........................................
19 to 21 VAC
TB21-1
to
2
..................................
.120 to 139 VAC
K11-B+
..............................................
12 VDC
K11-S
............................
.7 to
9
VDC ON CRANKING
K13-H
.................................
12 VDC
ON
PREHEAT
Jumper
battery
cable B+ connection
to
61
starker
solenoid terminal. Does engine crank?
+
FLOW
CHART
A.
ENGINE
DOES
NOT
CRANK
+
Check battery cables for clean and tight connections
(ref. Checkout
[B]).
Check
B7
starter solenoid and
motor
-
if bad, repair or replace.
START
Check
battery
per Checkout
[A]
and recharge or replace.
(NOTE: Centrifugal switch S1 and diode CRll can cause
battery discharge.
See
Checkouts
IC]
and
[HI).
Is battery dead?
-
With Si1 in
Start
position, does start solenoid K11
energize?
(Is
at least
7
volts DC present between
+
K11 terminal
S
and ground?)
Check solenoid K11, relay K12, Start/Stop switch S11
and associated wiring and connections per Checkouts
PI,
[El and
[GI.
1
Is
at least 7 volts DC present between B1 starter
solenoid terminal and ground? Check wiring and connections between K11 terminal
S
and the solenoid terminal of
81.
L
DIESEL ENGINE
t
(Also
see "Onan
Diesel
Starting Guide," page
71)
START
Does
fuel
transfer pump
El
and solenoid
K1
operate
when
SI
1
is
in
Start
position?
no
Check relays
K11,
K12
and
K14
per Checkouts
[D]
and
[E].
Check wiring. Replace transfer pump
El
if
defective.
Yes
I
Incorrect
fuel? (See Operator's Manual
recommendations.)
3
Does
fuel primer solenoid
K3
energize when
S11
is in
Start
position?
-
Check fuel supply system: fuel tank, shutoff valves, fuel
lines and connections, fuel filters and pumps.
Is
engine getting fuel? (Exhaust smoke should
be
blue-whiie. and fuel flow
steady
from fuel return
I
line.)
Check solenoid
K3
and related wiring. Repair or replace
as
needed.
I
I
Is carburetor choke operation proper?
-
Check heater solenoid
K13
and
switch
S12
per Checkouts
[D]
and
[GI.
Check wiring and heater elements.
Is
preheat
system operating properly?
Check electric choke components and wiring (if used).
.
Adjust per Operator's Manual instructions.
-no--,
f
I
GASOLINE
ENGINE
I
Yes
'1
I
Check ignition components: points, condenser, plugs,
distributor, wiring, and HETCO. Battery voltage must
appear at coil during cranking.
Is
ample spark ignition voltage available at
spark plugs?
I
L
I
c
Is
fuel pump
OK?
Does
fuel pulsate from line removed
at carburetor?
Use extreme care for this test. Run
fuel into
a
suitable container and
make sure area
is
well ventilated to prevent an explosion
or
flre
and
resulting
personal
injury
or
death.
I
I
I
Check fuel supply system: fuel tank, shutoff valves, fuel
lines and connections, fuel filters and pumps.
68
FLOW
CHART
C.
ENGINE
STARTS BUT STOPS
WHEN
START SWITCH
IS
RELEASED
Connect voltmeter from TB12-5 to ground.
Is
battery
voltage indicated as engine rpm increases?
START
Check centrifugal
switch
SI
and related wiring.
S1
should
close at about
900
rpm and connect battery
B+
to
-no-
TB12-5.
Connect voltmeter to other side
of
resistor
R11
(either at
relay KlPor Stop terminal
of
S11).
Is
batteryvoltage read
at rpm increase?
7
Check resistor
R11
per Checkout
[FJ.
If
OK,
check
relay
K12 switch S11 and related wiring for short
to
ground.
Jumper
normally
open
contacts
of
relay
K12
Does
engine
start
and run? no---,
'
Check wire between relay
K12
and ammeter M11.
Yes
1
I
Replace relay
K12
TROUBLESHOOTING DTNMDTA DC ENGINE CONTROL
Refer to Control Operation and the schematic
in
Fig-
ure
76
when troubleshooting
this
control. Repair
information
is
not extensive since the solid-state
printed circuit board lends itself more to replacement
than repair. External components such as leads,
switches, indicator lights, relays, gauge senders, cir-
cuit breakers, DCvoltage regulator, etc.,
plug
into the
board.
If
an external component
is
suspected
of
causing
a
problem, disconnect
its
associated jack
(51,
J2or
53)
from the board (Figure
80)
and check continuity
of
wiring
and the component. Note some switches are
NC
and some
NO
with
unit at rest. Individual compo-
nents can be checked out simularily as referenced
in
"Control Component Checkout" on page
70.
*
t
FIGURE
80.
LOCATION OF JACKS AND
RELAYS'ON
ENGINE MONITOR BOARD
300-1896
CONTROL
COMPONENT
CHECKOUT
The following component checkouts are referenced
in the Control Troubleshooting flow charts, pages 67
to
69.
They are an aid to isolating circuit problems
caused by faulty engine control components.
BATTERY CHECKOUT
Check charge condition of the battery with a hydro-
meter. The electrolyte specific gravity should be
about 1.260forafullycharged battery at
80”
F
(27OC).
If not, add approved water to keep electrolyte at
proper level and recharge the battery. If battery will
not recharge, replace
it.
If the battery loses excess water, the generator
charge rate may be set too high. Likewise, if battery
state of charge is not maintained, the charge rate may
be too low. Set charge rate per Adjustment Procedure
[C]
in the Generator Troubleshooting section (page
10).
BATTERY CABLE CHECKOUT
With the starter motor operating, check the voltage
drops
(1)
from the battery negative post (not the
cable clamp) to the cylinder block,
(2)
from the bat-
tery positive post to the battery terminal stud on the
solenoid. Normally, each
of
theseshould be less than
0.3
volt. If extra long battery cables are used, slightly
higher voltagedrops may result. Thoroughlyclean all
connections
in
any part of the circuit showing exces-
sive voltage drop.
RECTIFIER CHECKOUT
Disconnect one lead from, or remove, each rectifier
for its individual test.
Note
carefully the direction
of
mounting
of
any
rectifier removed.
I1
must
be
remounted
in
its
original
direction.
1.
Connect the ohmmeter across the rectifier con-
tacts and observe the meter reading.
2. Reverse the connections and compare
the
new
reading with the first reading.
3.
If one reading is considerably higher than the
other reading, the rectifier can be considered
satisfactory. However, if both readingsare low, or
if both indicate an “open” circuit, replace the rec-
tifier with a new identical part.
SOLENOID
CHECKOUT
8
1.
Apply 12 volts to battery terminal.
2. Jumper a ground wire to terminal marked
“S.”
Solenoid should activate.
3.
If contacts are good,
12
volts should be read
between terminal S1 and ground. The voltage
drop measured across contacts should never
exceed
1
volt
in
circuit application.
[El
RELAY CHECKOUT
1.
Connect 12 volts across relay coil terminals.
Relay should activate if coil is okay.
2. Connect
a
12-volt source to one side of relay
contacts.
3.
Connect a voltmeter to other side of relay contact
and 12-volt source. If 12volts appearswhen relay
is energized, contact is okay. The 12-volt reading
appears
in
reverse order when checking normally
closed
(NC)
contacts.
RESISTOR CHECKOUT
1.
Remove battery
B+
cable.
2. Disconnect one side of resistor and using an
ohmmeter measure across resistor for an accu-
rate reading.
SWITCH CHECKOUT
1.
Remove battery
B+
cable.
2. Place ohmmeter leads across switch.
3.
Activate switch. If meter reads continuity, switch
is good.
CENTRIFUGAL SWITCH CHECKOUT
The start-disconnect switch is located on the gear
cover on the side
of
the
engine above
the
oil filter. The
switch opens when theengine stops and closes when
the engine speed reaches about
900
rpm. Check the
switch contacts for pitting. If necessary, loosen the
stationary contact and adjust the point gap at 0.020
inch (0.51
mm).
Replace burned or faulty points.
70
ONAN
DIESEL
STARTING
GUIDE
IMPORTANT!
KEEP ENTIRE FUEL SYSTEM CLEAN AND FREE FROM
WATER
DIESEL INJECTION PUMPS
WILL
FAIL IF SYSTEM
CLEANLINESS IS NEGLECTED
INJECTION PUMPS
AND
NOZZLES ARE NOT FIELD
REPAIRABLE
WHEN TROUBLESHOOTING. CHECK ALL OTHER
COMPONENTS FIRST
WARNING
DO
NOT IEE ETHER STARTING
=
AIDS! ETHER
IS
EXTREMELY EX-
PLOSIVE AND MAY CAUSE SERIOUS PERSONAL IN-
JURY. ENGINE DAMAGE
IS
ALSO
LIKELY.
.
L
.-
FUEL TRANSFER
FUEL RETURN
NE CONNECTION
INJECTION PUMP
BEFORE STARTING:
I
CHECK FUEL SUPPLY. BE SURE SHUTOFF VALVES ARE OPEN.
I
I
PRIME FUELSYSTEM
IF:
FUEL FILTERS WERE DRAINED
OR
CHANGED,
SYSTEM WAS JUST INSTALLED. FUEL TANK RAN DRY.
TO PRIME PUMP. MOVE PRIMING LEVER UP AND DOWN UNTIL FUEL
a
FLOWS STEADILY FROM RETURN LINE (DISCONNECTED).
PREHEAT COLD ENGINE PUSH PREHEAT SWITCH AND HOLD
-
30
SECONDS
IF
ABOVE
%OF
(13oC);
60
SECONDS
IF
BELOW 55'F (13eC).
I
ENGAGE START SWITCH
TO START
RELEASE PREHEAT
'
STOP
I
LIMIT
CRANKING
TO
15
TO
20
SECONDS
TO
CONSERVE
BARRY.
ALLOW?
MINUTE
BEFORE
RE-
CRANKING.
I'
IF ENGINE DOES
NOT
STARE
IF
ENGINE
FIRED,
REPEAT
ABOVE PROCEDURES,
INCLUDING
PRE-
HEAT. IF IT STILL
DOES
NOT START, PROCEED AS FOLLOWS
I
TEMPERATURES
BELOW
320~ (ooc]: USE NUMBER
1
DIESEL FUEL USE CORRECT VISCOSITY OIL.
KEEP BATTERIES FULLY CHARGED.
DO
NOT USE ETHER STARTING AID.
I
I
_.
I
OBSERVE ENGINE EXHAUST "SIGNALS":
1
I
I
I
LITTLE
OR
NO
EXHAUST SMOKE ENGINE IS NOT GETTING FUEL.
PRIME FUEL SYSTEM
AS
SHOWN
ABOVE
OBSERVE FUEL FLOW
FROM
RETURN LINE
BLUE-WHITE EXHAUST SMOKE:
ENGINE
IS
GETTING FUEL
I
1
I
I
I
I
I
FUEL FLOWS STEADILY
CHECK PREHEAT SYSTEM:
1.
OBSERVE AIR HEATER THRU
AIR INLET HOLE
OR
BY REMOV-
ING AIR CLEANER.
2.
ENGAGE PREHEAT.
3.
IFHEATERELEMENTDOESNOT
GLOW RED WITHIN
30
SECONDS, CHECK AIR HEATER
AND GLOW PLUG WIRING
CONNECTIONS TIGHT?
FREE FROM CORROSION?
2-79 900-0217
I
CHECK
FUEL
SOLENOID
SOLENOID ROD SHOULD
PULL
IN
AND
THROlTLE
ARM
FOLLOW (AS SHOWN) WHEN
START SWITCH
IS
TURNED
ON. IF NOT, CHECK FOR
NG LINKAGE
E
OR
BROKEN WIRES
OLENOID
ROD
THROTTLE ARM
I
CHECK FUEL SUPPLY
SYSTEM:
FUEL TANK EMPTY?
SHUTOFF VALVES
CLOSED?
'
FUEL LINES KINKED?
LOOSE CONNECTIONS?
CLOGGED FUEL FILTERS?
I
IF ENGINE IS
STILL
NOT GETTING FUEL, CHECK TRANSFER PUMP:
1.
CRANK ENGINE AND OBSERVE FUEL
FLOW
FROM
RETURN
LINE.
2.
IF FUEL DOES NOT SPURT
OUT.
PUMP MAY BE DEFECTIVE.
I
IF ENGINE STILL DOES NOT START. CONTACT AUTHORIZED ONAN SERVICE REPRESENTATIVE
I
71
WIRING DIAGRAMS
The wiring and schematic diagrams
in
this section represent typical air-cooled, marine, and radiator cooled
engine driven YD generator sets. Wiring diagrams for special order generator sets are shipped with the units and
should be referred to whenever possible.
MODEL
DJB
DJC
DJB,DJE
DJC
MDJC
UDJE
MDJF
JB
JC
JB
JC
MJC
JC
RJC
RDJC
RJC
RDJC
JC
RJC
RDJF
MDTA/DTA
kW
RATING
4.5
&
6.0
(Code 18,518,3C, and
53C)
9.0
&
120
4.5
&
6.0
(with LOPswitch)
9.0
&
120
(with
LOP
switch)
1Q;O
7.5
12.0
&
15.0
6.0
&
7.5
15.0
6.0
&
7.5
(with 'LOP switch)
12.5
&
15.0
(with LOP switch)
10.0
& 15.0
12.5
(Code
18
&
518
120/240
V)
12.5
(Code
18
&
518
120/240
V)
17.5
(Code
18
&
518
120/240
V)
12.5
(Code
18
277/480
V)
17.5
(Code
18
277/480
V)
12.5
(Code 18
120/240
V)
12.5
(Code
18 120/240
V)
17.5
(Code 18
120/240
V)
25.0
(Code 3CR
&
15R)
RDJC/RDJF Engine Control
Voltage Regulator Assembly (Air-Cooled
Voltage Regulator Assembly (Radiator Cooled Sets)
and Marine Sets)
Typical Single-phase PTO Alternator
Typical Three-phase PTO Alternator
30.0
kW YD PTO Alternator Control
Typical Two-Bearing Alternator (Single and Three Phase
.
Typical Two-Bearing Alternator (Single and Three Phase)
with Circuit Breaker CB21)
DRAWING
NUMBER
61
2-4791
61 2-4791
61 2-4792
61 2-4792
61 2-4792
61
2-4B2
61 2-4792
61 2-4793
,612-4793
61 2-4794
61 2-4794
61 2-4794
61 2-481 6
61 2-481
6
61 2-481 6
61 2-4817
61 2-481 7
612-4818
61 2-481 8
61 2-481 8
61 2-5799
61 2-2730
305-0532
305-0534
305-0579
305061 8
620-01
55
620-01 56
620-01 93
620-0205
620-01 53
620-01
54
PAGE
73
74
75
76
77
78
79
80
81
82
83
84
84
85
88
87
87
88
88
NOTE: Special order generator sets with optional specification codes such
as,
4R-,4XR-,
and
5DR
-
60
Hertz:
5R
and
55R
-
50
Hertz; and
many others are basic
18R
-
60
Hertz or
518R
-
50
Hertz and
3C
-
60 Hertz
or
53C
-
50
Hertz generators. Optional meter equipment and
voltage output capabilities change the specification codes of these units and each wiring arrangement is slightly different.
72
I
I
>
0
c
I
73
I
I
I
L
I
Im
74
5
a
a
e,
2
5
0
B
f
0
u)
I
e,
a a
5
n
I
I
I
I
x
0
i
mi
$1
i
75
I
1'
t
I
I
U
I
p
WL
I-
CE
3
w
IW
o_
z
u)
I
It
I
I-
I
-----_..-
I
a
0
w
u
Y
L
80
I
I
I
I
I
I
I
I
$1
:I
a1
I
I
3
tl
de;
I
81
i
0
\
N
\
s
\"
0
\-
ai
0
Redistribution or publication of this document, 
by any means, is strictly prohibited.
P
83
RADIATOR COOLED SETS
PLKFMSM
CDMCTlDn
(Ill)
A.
XI
TO
YRI-¶
1.
x2
TO
n1-lo
0.
ws
TO
m-1
C.
HI
TO
TI24
p'p
@@
/
RADIATOR COOLED
AND PTO MODELS
/
/
/
'\
I\
r-
--1
.----
I"
I.
I
-1
85
I
86
~
"-
.I
\
e
6
a
i-
z
0
0
a
E
a
E
13
a
k
w
0
0
*
Y
3
8
@Y
87
5
88
I-
?$"
c
2
z
W
W
I
c
a
I
7
I
I
I
I
I
I
I
I
TERM
I
NAL
BLOCK
TB
1
I
6
Et
I
CIRCUIT
BREAKER
ICB
1
T
RAN
S
F
0
RME R
-
CUR
R
EN T
lCTl
.CT2
A
TI
b~
TL
I
4
3
2
I
----
t4
E
T
ER
-
F
RE
Q
U
E
N
C
7
METER-T
I
ME
I4ETER-AC
VOLTAGE
TOTAL
I
Z
I
NG
-e
M5
M3
I
REAR
VIEW
M
5
1.1
4
t;i
3
-
AC
WIRING DIAGRAM
-
ELECTRONIC REGULATION
50/6OHZ
C821
I
NOTES:
1.
CUT
LEADS
3
8
4
FROM L21.
THESE
LEADS
ARE
NOT
USED.
2.
UNLESS OTHERWSE
NOTED.
ALL
COMPONENTS ARE
SXQW
IN
DE-
ENEROltED
POSITION.
3.
DASMED
LINES
INDICATE
CONNECTIDNS
WEN
USE0
-
.-
1
I
I
I
I
_I
--
I'
i
I
1
I
I
I
I
I
I
I
I
I
I
I
I
Ii
-r-
TOP
EOOE
AC SCHEMATIC
-
ELECTRONIC REG
50/60HZ
T2
1
HI
XZ
RECONNECTION
OIAOXM
I
TRANSFORMER-VOLT REF
T21
CMR2
1
REACTOR
ASSY-COM
GENE2ATOR
(AC)
G2
1
C
I
RCU
I
T BREAKER-LOAD
CBZZ
C
I
RCU
I
T BREAKER-MAG
3A
CB2
I
REGULATOR-ASSY VOLT
VRZ
1
DEC;CTdF;TI&hl
LXI
MATErjkL
LZ
16
.
Onan
Corporation
1400
73rd
Avenue
N.E.
Minneapolis,
MN.
55432
1-800-888-ONAN
612-!574-5000 International
Use
Telex:
275477
Fax:
612-574-8087
Onan
is
a
registered
trademark
of
Onan
Corporation

Navigation menu