Cummins DL4 DL5 DL6T Generator Service Manual

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Service

Manual

DL4

DL6

DL6U

Generator

and

Controls

900-0336

8-83

(Replaces

900-0336 7/82)

Printed

in

U.S.A

Redistribution or publication of this document, 

by any means, is strictly prohibited.

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.

WARN,NG

personal injury.

This symbolis used throughout the

manual to warn of possible serious

This symbol refers to possible

equipment 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

'

shields and guards in position.

If

you must make adjustments while the unit

is

running, use extreme caution around hot manifolds,

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 extreine 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.

EXHAUST

GAS IS

DEADLY!

Exhaust gases contain carbon monoxide, a poisonous gas that might cause

unconsciousness and death. It is an odorless and colorless gas formed during

combustion of hydrocarbon fuels. Symptoms

of

carbon monoxide poisoning

are:

Dizziness Vomiting

Headache Muscular Twitching

'

Weakness and Sleepiness Throbbing in Temples

If you experience any of these symptoms, get

out

into fresh air immediately,

shut down the unit and do not use until it has been inspected.

The best protection against carbon monoxide inhalation is proper installation

and regular, frequent inspections of the complete exhaust system.

If

you notice

a change in the sound or appearance of exhaust system, shut the unit down

immediately and have it inspected and repaired at once by a competent

mechanic.

t

Redistribution or publication of this document, 

by any means, is strictly prohibited.

.

Table

of

Contents

I

.

TITLE

PAGE

SAFETY PRECAUTIONS

............................................

Inside Front Cover

TABLE

OF

CONTENTS

..............................................................

1

INTRODUCTION

...................................................................

2

About This Manual

................................................................

2

Test Equipment

....................................................................

2

GENERATOR AND VOLTAGE REGULATOR

.........................................

3

Generator Description

.............................................................

3

Generator Operation

..............................................................

4

Standard Voltage Regulator

........................................................

5

Switching Voltage Regulator

.......................................................

7

Generator Service

..................

.-.

............................................

10

GENERATOR/REGULATOR TROUBLESHOOING

....................................

13

Preparation

13

Troubleshooting Procedures

......................................................

13

GENERATOR/REGULATOR TESTS

.................................................

23

General

23

A

.

Testing AC Residual Voltage

..................................................

23

B

-

Testing

L21

Reactor

............................................................

23

C

-

Testing Rectifier Bridge Assembly

.............................................

23

D

-

Flashing the Field

..............................................................

23

E

-

Testing Reference Transformer T21

.............................................

24

F

-

VR21 Replacement

............................................................

25

G

-

Testing Rotating Rectifiers

....................................................

25

H

.

Testing Exciter Stator

.........................................................

25

J

-

Testing Exciter Rotor

..........................................................

26

K

-

Testing Generator Stator

......................................................

26

L

.

Testing Generator Rotor

........................................................

27

M

-

Wiring Harness Check

........................................................

27

N

.

Sensitivity Reference Circuit

...................................................

28

P

-

Voltage Adjustment

...........................................................

28

Q

-

Reconnection

.................................................................

29

R

.

Testing

QI

Capacitors

.......

:

................................................

29

S

-

Testing Standard Regulator

....................................................

29

T

-

Testing Switching Regulator

...................................................

32

ENGINE CONTROL

.................................................................

34

General

.........................................................................

34

Control Panel

....................................................................

34

Control Components

.............................................................

35’

Engine Sensors

..................................................................

36

Operation

38

ENGINE CONTROL TROUBLESHOOTING

..........................................

41

General

41

Flow Chart B

-

Engine Cranks But Does Not Start

..................................

42

Flow Chart C

.

Engine Starts But Stops After Running Several Seconds

...............

42

ENGINE CO NTR

0

L AD

J

USTM ENTS/TESTS

........................................

43

General

43

A

-

Battery Checkout

.............................................................

43

B

-

Battery Cable Checkout

.......................................................

43

C

-

Alternator Checkout

..........................................................

43

D

-

Solenoid Checkout

...........................................................

44

E

-

Relay Checkout

...............................................................

44

F

-

Fuel Solenoid Checkout

.......................................................

44

G

-

Switch Checkout

.............................................................

44

......................................................................

.........................................................................

.......................................................................

.........................................................................

Flow Chart A

.

Engine Does Not Crank

............................................

41

.........................................................................

WIRING DIAGRAMS

...............................................................

45

1

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Introduction

ABOUT

THIS

MANUAL

For servicing purposes, the generator set can be

divided into three basic parts: the engine, the genera-

tor, and the controls. This manual covers trouble-

shooting and repair information for the generator and

the controls. Refer to the

L

Engine Service Manual

(934-0750)

when servicing the engine.

This manual has separate sections for the generator

and voltage regulator, engine control, and associated

wiring diagrams. While the wiring diagrams at the end

of the manual are included to help trace or isolate

problems,

it

is suggested that service. personnel use

the wiring diagrams shipped with the unitfortrouble-

shooting.

Repair information for printed circuit boards is not

extensive because the solid state printed circuit

boards lend themselves more to replacement than

repair. Application of meters or hot soldering irons to

printed circuit boards by other than qualified person-

nel can cause unnecessary and expensive damage.

Repair of the printed circuit boards is not recom-

mended except by the factory.

A

return and exchange

service has been initiated whereby faulty printed cir-

cuit boards can be returned to the Distributor and

exchanged for good units. For more information,

contact your Onan Distributor.

High voltage testing or high poten-

tial (or Megger) testing

of

generator

windings can cause damage to solid state compo-

nents. Isolate these components 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 or

a

digital VOM. Some

other instruments

to

have available are:

0

Onan Multitester

0

Wheatstone Bridge

0

Kelvin Bridge

Jumper Leads

0

Onan Load Test Panel

0

Variac

0

AC

Voltmeter

DC Voltmeter

See Tool Catalog

900-0019.

I

WARNING

INCORRECT SERVICE OR REPLACEMENT

OF

PARTS MIGHT RESULT IN

SEVERE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE

PERSONNEL MUST BE QUALIFIED

TO

PERFORM ELECTRICAL AND/OR

MECHA NlCA L SERVICE.

2

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Generator

and

.Voltage Regulator

GENERATOR DESCRIPTION

The YD generator (see Figure

1)

is afour pole, revolv-

ing

field, brushless exciter design with drip-proof

construction. Several single and three phase models

are available in both

50

and 60 hertz. The generator

rotor is directly coupled to the engine flywheel with a

flexible drive disc. Engine speed determines genera-

tor output voltage and frequency.

A

centrifugal

blower (on the drive disc) circulates generator cool-

ing

air which is drawn

in

through the end bell and

discharged through an outlet

in

the blower end.

’

A

ball bearing

in

the end bell supports the outer end

of the rotor shaft. The end bell is attached with four

studs that thread into the stator (DL4 and DL6) or

generator adapter casting (DL6T).

C

I

The brushless exciter stator’mounts

in

the end bell

while the exciter rotor and its rotating rectifier

assemblies mount on the generator rotor shaft.

Within theend bell, leads

F1+

and F2-from theexciter

stator winding are connected to the output terminals

of the voltage regulator.

In

addition to the

AC

output leads, single phase gen-

erators have three control wires and three phase gen-

erators have five control wires that extend from the

stator housing (see Figure

2).

On single phase sets,

leads

1

and 4 (lead 2 is not used) are used for control

input and metering. On three,phase sets, leads 4,7,8,

9,

and

10

are used for control input and metering.

BLOWER

END

BELL

BRUSHLESS

EXCITER

ROTOR

FIGURE

1.

TYPICAL

YD

SERIES

GENERATOR

(DL4

and

DL6)

3

XG-1141

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Figure

2

is a composite illustration showing four output leads for

single-phase units,

12

output leads for 3-phase broad range units,

and

four output leads for code

7

and

9X

3-phase generators.

-

CONTROLAND

7bwR

LEADS

L

‘SINGLE-PHASE ONLY ES-1315

FIGURE

2.

SINGLE AND THREE PHASE GENERATOR

SCHEMATIC (COMPOSITE)

GENERATOR OPERATION

Operation

of

the generator involves the stator, volt-

age 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 the voltage build-up process as the 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 and fed into the

exciter field windings. The exciter armature produces

three-phase

AC

voltagethat 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.

*

Generator sets without

a

control panel

or

switch-

board 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 speci-

fied on the customer’s purchase order

to

deliver only

the voltage specified.

BRUSHLESS ROTATING GENERATOR

EXCITER DIODE ROTOR

ARMATURE ASSEMBLIES MAIN FIELD

----

4

EXCITER

FIELD

MAGNETISM

I

D-

I

--

STATOR

ASSY.

--

t

RESIDUAL

MAGNETISM

MAGNET STARTS

PROCESS (YD ONLY)

-

IN

PERMANENT

MAIN

I

RESIDUALMAGNETISM

FIELD IN ROTOR STARTS

PROCESS

MAGNETISM

---b-

-

GENERATOR

-

I

BRUSHLESS EXCITER STATOR

FIELD

I

VU-21

VOLTAGE

REGULATOR

ES-1322

FIGURE 3. EXCITATION BLOCK DIAGRAM

4

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by any means, is strictly prohibited.

..

-

STANDARD VOLTAGE REGULATOR

The voltage regulator shown in Figure

4

is standard

on

DL

series generator sets with the

YD

generator.

This regulator can be connected for frequencysensi-

tive, non-frequency sensitive, or semi-frequency

sensitive regulation. Unless requested, all sets are

connected at the factory for frequency sensitive

regulation.

Voltage Regulator Description

The voltage regulator controls the output voltage of

the generatorso that a constant voltage is maintained

under varying load conditions. Basic components of

the regulator are:

Printed circuit board VR21

Voltage reference transformer T21

Commutating reactor L21

SCR bridge rectifier CR21

All

components are located within the generator con-

trol box. The voltage regulator printed circuit board

(VR21) schematic diagram is shown in Figure

5.

Voltage Regulation Operation

The regulator assembly functions as follows: Current

from one of the generatorstator windings is supplied

to the primary side

of

the voltage reference trans-

former (T21). This produces 240voltsAC in the trans-

former secondary windings which is supplied as a

reference voltage to the regulator circuit board

(VR21).

A

rise or fall in the generator stator output

voltage will produce a corresponding change in the

output voltage from the reference transformer secondary

windings.

PC BOARD

VR21

8

I)

VOLTAGE REFERENCE

TRANSFORMER (T21)

SCR

BRIDGE (CR21)

TERMINAL BOARD

TB2

REACTOR (L21)

SEE NOTE WIRING HARNESS

ES-1318

A fixed resistor

(R21)

is used on generator sets WITHOUT optional

meters.

A

panel mounted potentiometer

(R23)

is used on generator

sets WITH optional meters.

8

FIGURE

4.

VOLTAGE REGULATOR ASSEMBLY

(305-0693)

5

Redistribution or publication of this document, 

by any means, is strictly prohibited.

REF.

NO.

C1.14

c2.

c7

c3

c4,.

c12

C5, C8

G6

c11

C13

CR3

CR12

CR13

CR14

F2. F3

1

c1

02

03

.

R1

R2, R3

R4

R5

R6

R7

R8,

R16

R10

R11 R9

Rl2

R13

R14

R15. R27

R17

R18

R20.22

R21

R24

R25. R31

R26

,

R28

TB

1

CR15

K1

R19

Thru

11

29

8.30

PART

DESCRIPTION

Board Assembly, Printed

-

Capacitor

-

47

Mfd. 250 Volt

Capacitor -.22 Mfd, 250 Volt

Capacitor -.47 Mfd, 400 Volt

Capacitor -A7 Mfd, 250 Volt

Capacitor

-

1

Mfd. 100 Volt

Capacitor

-

.33 Mfd, 250 Volt

Capacitor

-

d

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

-

1/2 Watt, 47-Ohm

Resistor

-

1/2 Watt, 33-Ohm

Resistor

-

2 Watt, 4.7 Meg-Ohm

Resistor

-

Fixed 10 Watt,

Resistor

-

Fixed 15 Watt,

Resistor

-

1/2 Wan, 3.000-Ohm

Resistor

-

112 Watt, 330.000-Ohm

Resistor

-

112 Watt.,51,100-0hm

Resistor

-

Fixed.5 Watt,

Resistor

-

1/2 Watt, 90,900-Ohm

Resistor

-

112 Watt, 10.000-Ohm

Resistor- 1/2 Watt, 220.000-Ohm

Resistor- 1/2Watt, 100.000-Ohm

Resistor, Metal Film

-

1/4

Watt,

11.000-Ohm

Potentiometer-5,WO-Ohrn.

1/2 Watt

.Complete

100 Mfd, 10 Volt

270-Ohm

5.000-Ohm

15.000-Ohm

Resistor

-

1/4 Watt, 28.000-Ohm

Resistor

-

Metal Film

-

1/4 Watt, 5.110-Ohm

Resistor

-

Metal Film

-

114 Watt, 8.870-Ohm

Resistor

-

2 Watt, 10.000-Ohm

:Potentiometer

-

112 Watt.

100,000-Ohm

i

Resistor

-

1/2 Watt .47 Meg-Ohm

'Terminal Block

Diode

-

Zener

-

24 Volt

j

Clip

-

Fuse

'Relay, Magnetic Reed

.,

Resistor

-

2 Watt, 6,800-Ohm

7

I

!

FIGURE

5.

REGULATOR

PC

BOARD

(332-2044)

,

Fc

6

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Generator stator current’is also supplied to the com-

mutating reactor (L21). Reactor L21 is achokethat is

used to produce a uniform AC wave. The output ter-

minals of the reactor supply AC current to the AC

input terminals on the rectifier bridge assembly

(CR21).

Rectifier bridge assembly CR21 is made up of two

silicon controlled rectifiers (SCR’s) and three recti-

fier diodes. The generator exciter field is connected

to the DC output terminals

(+

and

-)

on CR21. The

regulator circuit board (VR21) is connected to the

SCR gate terminals (G1 and G2). When a voltage

impulse from the regulator circuit board is applied

to

SCR gate terminals G1 and G2, input AC current from

L21 is rectified to DC current which is then supplied

to the exciter field.

Rectification of AC current to DC current proceeds

until the input AC voltage wave falls to zero. At this

point, rectification of AC to DC stops. As the AC

voltage wave begins to build again, avoltage impulse

is

again applied to the SCR gate terminals G1 and G2

by the regulator circuit board. This initiates a new

rectification cycle.

The voltage of the DC current produced at the output

terminals of CR21

(+

and

-)

is dependent on when the

rectification process begins. If a voltage impulse is

applied to the SCR gate terminals early in the AC

wave cycle, the DC voltage is higher.

If

the voltage

impulse is applied later

in

the AC wave cycle, the DC

voltage is lower.

During operation, the regulator circuit board re-

sponds to changes in the reference voltage supplied

by the voltage transformer.

If

the reference voltage is

low, the circuit board supplies a voltage impulse

to

the SCR gate terminals early in the AC wave cycle.

This raises thevoltage of the DC current produced for

field excitation which results in an increase in the

generator output voltage. If the reference voltage

supplied

to

the regulator circuit board is high, the

circuit board supplies a voltage impulse to the SCR

gate terminals later in the AC wave cycle. This lowers

thevoltage of the DC current produced for field exci-

tation which results

in

a decrease

in

the generator

output voltage. The process of continuously sensing

changes

in

the generator output voltage and adjust-

ing the voltage supplied to the exciter field is how

regulation is achieved.

..

SWITCHING

VOLTAGE

REGULATOR (Optional)

The switching voltage regulator is available as an

option on DL series generator sets. This regulator

can provide frequency sensitive, non-frequency sen-

sitive, or semi-frequency sensitive regulation. All sets

are connected at the factory for frequency sensitive

regulation. Aseparate printed circuit board assembly

is used for each method of regulation.

The switching voltage regulator

is

recommended

when the generator set must power non-linear SCR

loads (usually associated with solid-state

equipment). The voltage sensing circuitry in the

standard regulator tends to overreact to the switch-

ing transients created by SCR loads. This can result

in erratic voltage regulation. The switching regulator

is designed to overcome this limitation.

Voltage Regulator Description

The voltage regulator controls the output voltage

of

the generator

so

that a constant voltage

is

maintained

under varying load conditions. Basic components

of

the regulator are:

Printed circuit board VR21

Voltage reference transformer T21

Commutating reactors L21 and L22

Capacitors C1 (single phase only)

All componentsexcept the C1 capacitors are located

within the control box. When used, the C1 capacitors

are mounted within the generator output box. The

switching voltage regulator assembly is shown

in

Figure

6.

The voltage regulator printed circuit board

(VR21) schematic diagram is shown in Figure

7.

Voltage

..

.

Regulator Operation

The regulator assembly functions as follows:

Current from one of the generator stator windings is

supplied to the primary side of the voltage reference

transformer (T21). This produces 240 volts AC in the

transformer secondary windings which is supplied as

a reference voltage to the regulator circuit board

(VR21) A rise or fall in the generatorstator output

will

produce a corresponding change in the output volt-

age from the reference transformer secondary

windings.

7

Redistribution or publication of this document, 

by any means, is strictly prohibited.

PC BOARD

VR21

8

1234567831011I~

VRZl

8

TBI

COMMUTATING

REACTORS

(L21

&

L22)

FIGURE

6.

VOLTAGE REGULATOR ASSEMBLY

(305-0695-02)

Generator stator current is also supplied to the com-

mutating reactors

L21

and

L22

(three phase only).

These reactors are used to produce a uniform AC

wave. The output terminals of the reactors supply AC

current to the power circuit on the regulator circuit

board

(VR21).

The power circuit primarily consists of a power tran-

sistor

(Q4),

pulse transformer; (TI), and rectifying

diodes. When the power transistor is turned on, AC

current from the commutating reactors

is

rectified to

DC and supplied to the exciter field. The current flow

stops when

the

power transistor is turned off. The

voltage of the DC output is directly proportional

to'

the on-off switching frequency of the power transis-

'

tor. An increase or decrease in the switching fre-

quency causes a corresponding increase or decrease

in the DC voltage produced. The nominal switching

frequency is approximately

125

Hz.

The pulse transformer T1 is used to trigger the firing

of the power transistor. Triggering is accomplished

by reverse saturating the transformer and then releas-

ing

it.

This initiates conduction

in

the power transis-

tor which remains on until the transformer saturates

in the forward direction. Using the pulse transformer

to trigger the power transistor helps isolate the power

circuit from the voltage regulating circuit.

8

Redistribution or publication of this document, 

by any means, is strictly prohibited.

w1

VR2

VR1

u3

u2

u1

TB1

T2

T1

R36

R34.35

R33

R32

R30

R29

R28

R24

R22

R20

R19

R18

R17

R15

R14.21

R13

R12

R11

R10

R9

R8

R7, R16

R6

R5

R3,4

R2

R1

Q4

Q3

Ql, 2

K1

CR28

CR9, 15, 22-27

CR3,5

14.16-21

&

29

cdi

,2,4.6,7,a

C15

C14

C13

c11

c10

c9

C7,12

C6,8

c5

c4

c3

c2

c1

Wire Jumpgr,

1"

Diode -Zener

Diode -Zener (5W)

IC

f

12 Volt Regulator

Integrated Circuit

1 C -Timer

Terminal Block

Transformer (1 15/230

V,

50/60

Hz)

Transformer

-

Pulse

Potentiometer (10 K, 1/2W)

Resistor (61.9 K, 1/2W, 1%)

Resistor (28

K,

1/4W, 1%)

Resistor (51.1K. 1/4W, 1%)

Resistor (2.2M. 1/2W,

5%)

Resistor (15K, 5W, 5%)

Resistor (5.1K, 2W,

5%)

Resistor (220K, 1/2W,

5%)

Resistor (330K, 1/2W,

5%)

Resistor (100n 1/2W,

5%)

Resistor (lOK, 5W,

5%)

Resistor (lM, 1/2W,

5%)

Resistor (4.7K, 1/2W,

5%)

Resistor (220K, 1/2W,

5%)

Resistor (100 K, 1/2W,

5%)

Resistor (5.1 K, 1/2W, 5%)

Resistor (1.2 K, 1/2W,

5%)

Resistor (2.7K, 1/2W.

5%)

Resistor (62K, 1/2W,

5%)

Resistor (27K, 1/2W,

5%)

Resistor (68K, 1/2W,

5%)

Resistor (47K. 1/2W,

5%)

Resistor (150

n,

2W,

5%)

Potentiometer (loOK, 1/2W)

Resistor (lOK, 1/2W,

5%)

Resistor (2.2 K. 1/2W,

5%)

Resistor (270

0,

low,

5%)

Power Transistor

-

Silicon (NPN)

Transistor

-

Silicon (NPN High Volt)

Transistor

-

Silicon (PNP)

Relay

Rectifier

-

Fast Recover

Rectifier

-

Silicon

(6A,

800V)

Diode

-

Fast Switching

Rectifier

-

Silicon (lA, 800V)

Capacitor (4000 MFD. 30V)

Capacitor

-

Metalized (.33 MFD, 400 V)

Capacitor

-

Metalized (.001 MFD, 100OV)

Capacitor

-

Metalized (.47 MGD .250V)

Capacitor

-

Metalized

(

1

MFD, 1OOV)

Capacitor

-

Metalized (.l MFD, 1OOV)

Capacitor

-

Metalized (.22 MFD, 630 V)

Capacitor

-

Metalized (.l MFD 250 V)

Capacitor

-

Metalized (1 MFD, 400V)

Capacitor

-

Metalized (.47 MFD, 400V)

Capacitor (10 MFD. 20V)

Capacitor

-

Monolytic (.22 MFD, 50V)

Capacitor

-

Metalized (.047 MFD. 250 V)

1

L-J

FIGURE

7.

REGULATOR

PC

BOARD

(300-2409)

9

Redistribution or publication of this document, 

by any means, is strictly prohibited.

The basic regulating circuit performs several func-

tions.

A

voltage sensing circuit samples the generator

terminal voltage by sensing changes in the output

voltage from the reference transformer T21. The AC

output from T21 is rectified to DC and fed to the

sensing side of the error detector circuit (U2). The

error detector compares the sensed voltage with a

constant

DC

zener diode regulated voltage. The dif-

ference is amplified and fed to the control section of a

voltage controlled variable frequency oscillator (UI).

The oscillator responds to changes in thevoltage fed

to its control section by increasing or decreasing the

oscillation frequency. The current pulses produced

by the oscillator are fed to the pulse transformer

which triggers firing of the power transistor.

By

modifying the rate of current pulses fed to the

pulse transformer, the DC field voltage can be con-

trolled. This allows the generator terminal voltage to

be maintained within specified limits.

Several additional circuits are used to improve the

operation and efficiency of the regulating circuit.

However, the basic regulating functions are per-

formed as described.

GENERATOR

SERVICE

The following sections describe the disassembly and

reassembly procedures for the generator.

Accidental starting

of

the set might

I--.

cause severe personal injury or

death. Disconnect the negative battery cable when

repairs are made to the engine, controls, or

generator.

Disassembly

WARNING

1.

Disconnect the negative

(-)

battery cable to pre-

vent accidental starting of the generator set while

servicing

.

2. Remove the generator output box cover (see Fig-

ure

8)

and disconnect the stator lead wires from

the load wires.

3.

Unplug the control wiring harness from the

underside of the control box.

4. Remove the overspeed switch bracket and switch

assembly from the end bell.

5.

Remove the upper and lower brackets that secure

the output box to the end bell.

6.

Remove the end bell stud nuts and slide off the

end bell and exciter stator assemby (see Figure

9).

It may be necessary to tap around the joint to

separate the end bell from the stator assembly.

7.

Loosen the screws that fasten the output box to

t.he generator and remove the output box and

control box as an assembly.

8.

Usea hoist and safe lifting device (stator han'dling

tongs or chain and lift hooks) to support the sta-

tor assembly as shown in Figure

9.

On DL4 and

DL6 sets, carefully remove the capscrews from

the stator attachment ring.

'

CONTROL CONTROL WIRING.

HARNESS

\

FIGURE

8.

OUTPUT

BOX

AND CONTROL

10

Redistribution or publication of this document, 

by any means, is strictly prohibited.

STATOR

LIFF

G-1153

FIGURE 9. GENERATOR ASSEMBLY

11

Redistribution or publication of this document, 

by any means, is strictly prohibited.

9.

10.

11.

12.

13.

14.

15.

Remove the stator assembly being careful not to

touch or drag on the rotor. Place stator on its side

in the horizontal position. On DL6T sets, remove

the four end bell studsfrom the generator adapter.

Using a hoist and sling to support the rotor, care-

fully remove the capscrews that attach the drive

disc to the engine flywheel (Figure

9).

Remove the rotor assembly and place

it

on wood

blocks in the horizontal position. The drive disc

and fan should not be resting on anything to

av0i.d possible distortion.

Remove the bolts that hold the drive disc to the

rotor shaft and remove the drive disc and rotor

fan.

Use a gear puller to remove the end bearing from

the rotor shaft (Figure

IO).

Clamp the rotor in afixed position and remove the

exciter rotor lock nut.

Remove the generator field leads from the exciter

rotor and slide the exciter off the rotor shaft.

..

FIGURE

10.

END

BEARING

REMOVAL

Reassembly

1.

2.

3.

4.

5.

6.

Slide the exciter rotor over the generator shaft

and install the exciter lock nut. Torque to

130

to

150

ft.

Ibs. (176 to

203

Nom).

Connect generator field leads to

F1+

and

F2-

terminals

on

exciter assembly. Torque to

23

to

26

inch Ibs.

(2.6

to

2.9

Nom).

Press the end bearing onto the rotor shaft.

Place the generator fan in position on the rotor

shaft.

Install the drive disc on the end of the rotor shaft

with the chamfer on the flywheel side. Torque the

8

placement bolts to

70

to

80

ft. Ibs.

(95

to

108

Nom).

Using a hoist and sling to support the rotor, align

the holes in the drive disc and fan with the corres-

ponding holes in the flywheel.

7.

Install the

8

capscrews that hold the drive disc to

the engine flywheel and torque to

39

ft. Ibs. (52

Nom).

8.

Using a hoist and safe lifting device, carefully

move the stator into position over the rotor

assembly. The stator leads should be at the 4

o’clock position when viewed from the end bell

position.

9.

On DL4and DL6sets, align the holes in thestator

attachment ring with the holes in the flywheel

housing and install the

12

capscrews. Torque to

39

ft. Ibs.

(52

Nom). On DL6T sets, install the end

bell studs

in

the generator adapter.

10.

Install the control box assembly.

11.

Apply a thin film of Molykotegrease or equivalent

to the mating surfaces of the end bearing and the

end bell bearing hole.

12.

Install end bell assembly on the stator with the

opening for the generator leads in the 4 o’clock

position. Torque end bell stud nuts to

20

ft. Ibs.

(27

Nom).

13.

Using a lead hammer, tap the end bell at the

horizontal and vertical plane to relieve stress.

Retorque end bell stud nuts.

14. Install the upper and lower output box brackets.

15.

Plug in the control wiring harness and connect

the stator lead wires to the load wires. Refer to

Figure 26 for the generator voltage connections.

16.

Install the overspeed switch assembly and switch

bracket.

17.

Verify that all connections are secure and then

install the output box cover.

18.

Connect the negative

(-)

battery cable and test

generator for operation.

12

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Generator/Regulator Troubleshooting

PREPARATION

A few simple checks and a proper troubleshooting

procedure can locate the probable source of trouble

and reduce down 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 absolutely sure that panel instruments are

accurate, use portable test meters for trouble-

shooting.

0

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 circuit between components.

TROUBLESHOOTING PROCEDURES

The information in this section is for both single and

three phase YD generators using the standard UR

type voltage regulator or the optional switching volt-

age regulator. Determine the problem and then refer

to the appropriate Flow Chart (A,

6,

C, D,

or

E)

for the

troubleshooting procedures.

A. NO AC OUTPUT VOLTAGE AT RATED ENGINE

RPM.

B. UNSTABLE OUTPUT VOLTAGE, ENGINE

SPEED STABLE

1800

RPM.

C. OUTPUT VOLTAGE TOO HIGH OR

LOW.

D.

EXCITER FIELD BREAKER TRIPS.

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 schematics (Figure

11

and 12) and on

assembly drawings and wiring diagrams.

13

Redistribution or publication of this document, 

by any means, is strictly prohibited.

L

-

DC

OUTPUT

VOLTAGE

F2-

I:

I

4-9

I

,8(,)

7(4)

'I

-I

EXCITER

I

F1+

\\

..

BRUSHLESS

EXCITER

ROTOR

(30.

WYE) ASSEMBLIES

ES-1377-1

FIGURE

11.

YD GENERATOR AND STANDARD VOLTAGE REGULATOR

14

Redistribution or publication of this document, 

by any means, is strictly prohibited.

I

.I

'I

1

I

r

H2

X2 RED

VU

21

TB1

I

112

1

.

...

.. ...

SEENOTE1

.

..

.

I

SEE

NOTE

2

NOTE

1.

CAPACITOR ASSEMBLY USED

FOR

SINGLE PHASE INSTALLATIONS ONLY.

NOTE

2.

L22 AND

CB4

USED

FOR

THREE

PHASE INSTALLATIONS ONLY.

STATOR

10,

EXCITER

ROTOR

(3v).

WYE)

-

ROTATING

F2-

GENERATOR

R

ECTl

FI

ER

ASSEMBLIES

I

ES-1421

FIGURE

12.'

YD

GENERATOR AND SWITCHING VOLTAGE REGULATOR

15

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW CHART A. NO AC OUTPUT VOLTAGE AT RATED ENGINE RPM

STANDARD VOLTAGE REGULATOR

.

Test voltage regulator assembly per

procedure

(S).

Replace the regulator

PC

board per procedure

(F)

if

START

Replace defective

field breaker.

ohmmeter.

Is

breaker open?

b

I

Is

control panel field

breaker CB3

ON?

If voltage is unstable, high or

low.

or

causes breaker

to

trip, see Flow Charts

B,

C.

D. or E.

Push

to

reset breaker. Does generator

AC output voltage build up?

Is

residual voltage across TB2-2 and H1

5

to 10 VAC or more? Flash exciter field per TEST [D]. Does

generator output voltage build up?

.

1

Disconnect stator leads

7

(4)

and

8

(1) from TB2-2

and H1.

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 TB1-5

&

6

5

VDC

or

more? TEST [C].

Check diodes and

SCR’s

on

bridge assembly CR21 per

yis

1

Check exciter field wiring

harness per TEST [MI.

I

Check fuses F2 and F3 for

continuity on VR21 regu-

lator PC board.

t

i

I

Check exciter field winding

per TEST [HI. Replace

if bad.

The newprinted circuit boardmight

be damaged

by

malfunctioning

co’mponents within the control.

Do

not install the new

PC

board until all other problems have been located

and corrected.

I

no

J.

Check lead continuity between

TB2-2 and

8

(1) on generator, and

I

Check exciter rotor winding

per TEST [J]. Replace if bad.

I

+

Check generator rotor field

winding per TEST

[L].

I

Check generator stator wind-

ings per TEST [K]. Replace

if

bad.

16

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW

CHART

B.

UNSTABLE

VOLTAGE,

ENGINE

SPEED'STABLE

1800

RPM

STANDARD VOLTAGE REGULATOR

--Yes

-

Are there any broken wires or loose connections

on voltage regulator assembly? Repair as required.

I

1

I

Check wiring harness from regulator assembly

to end bell per TEST [MI. Check

OK?

-no+ Repair wiring or replace as required.

yes

Test voltage regulator assembly per

procedure

(S).

Replace the regulator PC

board per procedure

(F)

if

defective.

1

Does adjustment of Dampening Control R26 on VR21

per adjustment [PI result in stable

voltage? set?

Is

voltage stable within spec at no

load to full load range

of

generator

--yes

+

be damaged by malfunctioning

components within the control.

Do

not install the new

I

no

I

no

Is

engine running at correct RPM?

-

no----, Set RPM per instructions in appropriate

engine manual.

Does adjustment of control R18 on VR21 result

in correct output voltage?

-

yes----,

I

yes

Set per Voltage Calibration Adjustment [PI.

I

Are reference transformer (T21) tap connections

correct and secure on TBl? See TEST

[Q].

Does adjustment of Voltaga

-an

-

.

-

I

-

_-

-I

_,I

Are generator output leads properly connected?

b

See Figure 26.

no

-1

Test voltage regulator assembly per

procedure

(S).

Replace the regulator PC

b,oard per procedure (F) if defective.

-

I

.

1

I I

The new printed circuit board might

be damaged by malfunctioning

components within the control.

Do

not install the new

PC board until all other problems have been located

and corrected.

1

17

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW

CHART

D.

EXCITER

FIELD

BREAKER TRIPS

STANDARD VOLTAGE REGULATOR

I

b

Check generator rotor field winding per

TEST

[L].

Replace

if

bad.

START

1

I

1

Check generator stator windings per TEST [K].

Replace

if

bad.

I-

Does AC output voltage build up to 15O0/o0r

more of rated voltage before breaker trips?

kyes-l

Check for any loose or broken wires or connections

on VR21 assembly.

I

1

Check exciter stator winding per TEST [HI.

Replace

if

bad.

I

v

I

Check exciter rotor winding per TEST

[J].

Replace

if

bad.

Check diodes and SCR's

in

bridge assembly

CR21 per TEST [C].

I

Check reference transformer T21 and connections

per TESTS [E] and [a]. Replace if bad.

Check generator stator leads for proper

connection. See Figure

26.

I

1

The new printed circuit board might

be damaged by malfunctioning

components within the control.

Do

not install the new

,

PC

board until all other problems have been located

and corrected.

Test voltage regulator assembly per

procedure

(S).

Replace the regulator PC

board per procedure

(F)

if defective.

18

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW CHART

E.

UNBALANCED GENERATOR OUTPUT VOLTAGE

STANDARD

AND

SWITCHING VOLTAGE REGULATOR

no

-

Are generator leads connected and grounded

properly? See Figure

26.

START

Remove load at generator terminals. Is output

still unbalanced? and load.

Check for correct grounding

of

generator

yes

Correct as necessary.

1

yes

I

Is

generator stator winding continuous per Replace stator assembly.

Is

generator stator winding continuous per Replace stator assembly.

yis

Check load

for

ground faults and correct as

necessary.

19

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW

CHART A. NO AC OUTPUT VOLTAGE AT RATED ENGINE RPM

SWITCHING VOLTAGE REGULATOR

~

-

-~

Push to reset breaker. Does generator

.

AC output voltage build up?

Replace defective

field breaker.

and check continuity with

Are field circuit breakers

If voltage is unsta

B, C,

D,

or

E.

-yes

*

causes breaker to

J

io

1

I

i"

A

\

ble, high or low. or

trip, see Flow Charts

Check lead continuity between the following

terminal points and the generator per Test

M.

TB2-2 and T8 (1

0

-lead 1)

TB2-H1 and T7 (1

0

-lead

4)

TB2-1 and T9

'

I

Check diodes CR1 through Ck6

on rotor per'TEST

[GI.

Re-

place if bad.

i

I

no

I

Check exciter field winding

per TEST [HI. Replace

if bad.

T

ves

Is

residual voltage across TB2-2 and H1

5

to 10 VAC

or

more? Flash exciter field per TEST [D]. Does

generator output voltage build up?

ti0

I

+

Disconnect stator leads 7

(4)

and

8

(1) from TB2-2

and H1.

Is

residual voltage across leads

5

to 10

VAC

or more now?

-yes-

Check reactors L21, L22

(30),

and transformerT21 pertests B

and E.

I

Is

exciter field voltage

5

volts DC

or more between TB1-5

and TB1-1 l?

no

1

Check exciter field wiring

harness per TEST,

[MI.

1

I

regulator assembly per

procedure (T). Replace the regulator

PC

board per procedure (F) if defective.

.

Check C1

capacitorsforopensorshorts

perTest

R

Replace if bad.

Contact with high voltage

might cause serious,

personal injury or death. Avoid contact with

capacitor terminals. Dangerous voltage might be

present up to a minute after set shutdown.

1

m.

Thenewprihfed circuit boardmight

be damaged by malfunctioning

components within the control.

Do

not install the new

PC

board until all other problems have been located

and corrected.

1

Check generator rotor field

winding per TEST

[L].

Replace if bad.

Check generator stator wind-

ings per TEST [K]. Replace

if bad.

,

20

Redistribution or publication of this document, 

by any means, is strictly prohibited.

c

.no.

+

Check wiring harness from regulator assembly

to end bell per TEST

[MI.

Check OK?

FLOW CHART B. UNSTABLE VOLTAGE, ENGINE SPEED STABLE

1800

RPM

SWITCHING VOLTAGE REGULATOR

START

..

Repair wiring

or

replace as required.

Are there any broken wires or loose connections

on voltage regulator assembly?

Does adjustment of Dampening Control

R5

on VR21

per adjustment [PI result in stable

voltage? -yes

II)

I

Repair as required.

Is voltage stable within spec at no

load to full load range of generator

set?

I

Is engine running at correct RPM?

-

no--.)

IiO

Set RPM per instructions in appropriate

engine manual.

-1

-yes

4

Does adjustment

of

control

R36

on

VR21

result

in correct output voltage? Set per Voltage Calibration Adjustment [PI.

Are reference transformer (T21) tap connections

correct and secure on TBl? See TEST

[a].

$.

~~

Test voltage regulator assembly per

procedure

(S).

Replace the regulator PC

board per procedure

(F)

if defective.

*

Are generator output leads properly connected?

See Figure 26.

The new printed circuit boardmight

be damaged by malfunctioning

components within the control.

Do not install the new

PC

board until all other problems have been located

and corrected.

FLOW CHART C. OUTPUT VOLTAGE TOO

HIGH

OR LOW

SWITCH

IN

G VOLTAGE REGULATOR

ge

Latiorailon

no

Does adjustment of Voltage Adjust control

R23

on

control panel result in correct output

voltage?

Set control per Voltal

*"

.'

Adjustment [PI.

I

no

The newprinted circuit boardmight

be damaged by malfunctioning

components within the control.

Do

not install the new

PC

board until all other problems have been located

and corrected..

Test voltage regulator assembly per

procedure (T). Replace the regulator PC

board per procedure (F) if defective.

21

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOW CHART

D.

EXCITER FIELD BREAKER TRIPS

SWITCHING VOLTAGE REGULATOR

Check for any loose or broken wires or connections

on VR21 assembly.

Does AC output voltage build up

to

150% or

more of rated voltage before breaker trips?

Check generator rotor field winding per

TEST

[L].

Replace if bad.

I

t

Check generator stator windings per TEST

[K].

Replace if bad.

1

Check generator stator leads for proper

connection. See Figure 26.

1'

Test voltage regulator assembly per

procedure (T). Replace the regulator PC

board per procedure

(F)

if defective.

The

newprintedcircuitboardmight

be damaged by malfunctioning

components within the control.

Do

not install the new

PC

board until all other problems have been located

and corrected.

22

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Generator/Regulator Tests

'

GENERAL'

.

All of the following Adjustments and Tests can be

performed without disassembly of the generator.

They should be used for testing generator regulator

components in conjunction with the troubleshooting

flow charts.

.

[AI

TESTING AC RESIDUAL VOLTAGE

Test for residual AC voltage if there is no AC power

output from the generator. Check between terminals

2 and

HI

on TB2 (Figures

11

and 12). Residual volt-

age should be

5

to

10

VAC. If none, flash the field per

Test (D)

.

If

residual voltage is present at TB2, proceed to PC

board

VRI.

On sets with the standard regulator,

check between terminals

1

and 2 on TBI (Figure

11).

On sets with the switching regulator, check between

terminals 2 and 3 on TBI (Figure 12). If no voltage is

present, check continuity between these points with

the generator shut down. If voltage is low, check

reactor (Test

B)

and T21 transformer (Test

E).

TESTING COMMUTATING REACTORS

The L21 and L22 commutating reactors (Figure 13)

mount inside the control box. Remove reactor leads

from terminal board for testing.

The coils 1-2 and 3-4 are wound on the same core.

Resistance between 1-2 and 3-4 should be .031 to

0.37 and .037

to

0.46 ohms respectively at 77°F

(25OC). Resistance between coils and from any ter-

minal to frame of the reactor should be infinity.

FIGURE

13.

COMMUTATING REACTORS

TESTING RECTIFIER BRIDGE

ASSEMBLY (CR21)

The rectifier bridge located within the control

cabinet, contains 3 diodes, CRI, CR2 and CR3, and

two silicon controlled rectifiers, SCRI 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

14.

Disconnect wires from rectifier unit prior to testing.

Test unit inordershown inTable1. RefertoFigure15

for SCRI and SCR2 test circuit. When test is com-

,

plete and satisfactory, reconnect unit observing cor-

rect wiring hook-u

p.

AC TERMINALS ARE

GIVEN NUMERIC

DESIGNATIONS FOR

TEXT REFERENCE

ONLY. DOES NOT

APPEAR ON UNIT.

IIL

FIGURE

14.

RECTIFIER BRIDGE ASSEMBLY

CDI

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 6-volt battery, IO-ohm resistor, and

diode as shown in Figure 16.

23

Redistribution or publication of this document, 

by any means, is strictly prohibited.

--1

I

-p

OOR

I

6

VOLT

t

r----

t

DC

VOLTMETER

6

VOLT

DRY

CELL

BATTERY

FIGURE 15. TESTING CR21

If a 6-volt lantern battery is not available, a 12-volt or

'

24-volt generator set battery can be used. However, a

20-ohm or a 40-ohm, 2 watt resistor must be used in

series respectively with the 12 amp

300

V

diode. Start

,

the generator set and operate at normal rpm. Touch

the positive

(+)

lead to terminal TB2-4 and the nega-

tive

(-)

lead to terminal TB2-5. Hold leads on termi-

nals just long enough for voltage to build up.

TB2-5

TB2-4

$:

Incorrect flashing procedure can

'

damage the voltage regulator.

Do

not keep excitation circuitry connected longer than

5

-

seconds.

PLACE RESISTOR HERE

6

V

-

Use

10

f2

12

V

-

Use

20

f2

24

V

-

Use

40

f2

---

.-

.

-

ES-1420

6

VOLT

DRY CELL

BATTERY

FIGURE 16. FIELD FLASHING CIRCUIT

TESTING REFERENCE

..

.

TRANSFORMER T21

Transformer T21 has eight leads;

six

are primary

leads marked

HI

through H6, two are secondary

leads marked

X1

and

X2.

TABLE

1.

TESTING RECTIFIER BRIDGE ASSEMBLY CR21

*

-

Apply temporary jumper

from

AC1' to

G1

to test

SCRl.

Remove jumper and read voltmeter.

See Figure 15.

**

-

Apply temporary jumper from AC2 to

G2

to test SCR2. Remove jumper and read voltmeter.

SeeFigure15.

24

Redistribution or publication of this document, 

by any means, is strictly prohibited.

The winding schematic (Figure 17) shows the resist-

ance values for the individual coils

in

ohms. Resist-

ance between any primary and secondary leads and

from any lead to transformerframeshould be infinity..

L

HO

350-427

OHMS

c

333-407

OHMS

c-

303-371

OHMS

-

H3

r

282-344

OKMS1

531-649

OHMS

4

x1

x2

VR21-9

VR21-10

FIGURE 17. T21 WINDING SCHEMATIC

VR21 REPLACEMENT

Use the following procedure for replacing the voltage

regulator PC board or

VR

chassis.

1.

2.

3.

4.

5.

6.

7.

8.

b

9.

Stop engine.

Disconnect and if necessary, label wires. 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

1

terminals.

1

Place jumper W12 at proper terminals for your

I

particular voltage code and voltage connection.

See Test Procedure

[Q].

Adjust the voltage and stability potentiometers as

indicated:

Standard Regulator

-

Turn R18 fully counter-

clockwise and R26 fully clockwise.

Switching Regulator

-

Turn

R5

and R36 fully

cloc kwise.

Perform voltage calibration and stability adjust-

ment procedures to obtain the correct generator

output voltage and stability with new PC board

in

set. Refer to test (P).

[GI

.

TESTING ROTATING RECTIFIERS

Two different rectifier assemblies make up the rotat-

ing rectifier bridge assembly, Figure 18. 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 'CR1, CR2, and CR3 in turn; record

resistance value of each rectifier.

3. Connect one lead to F2- stud and connect other

lead to CR4,

CR5,

and CR6 in turn; record resist-

ance value of each rectifier.

4. Reverse ohmmeter leads from steps 2 and 3 and

record resistance value of each rectifier

F1+

to

CR1, CR2, and CR3-and F2-

to

CR4; CR5, and

CR6.

5.

All the resistance readings should be high in one

test and low

in

the othertest. If any reading is high

or low in both tests, rectifier assembly is defective.

6. 'Replace defective rectifier assembly with new,

.

identical part.

Use

24 Ibs-in. (2.7

Nom)

torque

when

replacing nuts

of

F1+ and F2-,

CR1, CR2, CR3, CR4, CR5, and CR6.

FIGURE 18. TESTING ROTATING RECTIFIERS

TESTING EXCITER STATOR

Testing the exciter stator (Figure 19) 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

77O F (25' C).

Testing

for

Grounds

Connect ohmmeter between either field lead and

exciter stator laminations. Use ohmmeter set at the

highest resistance range. Resistance must be one

megohm (1,000,000 ohms) or greater.

25

Redistribution or publication of this document, 

by any means, is strictly prohibited.

OHMMETER RESISTANCE BETWEEN

F1

AND

F2

SHOULD BE

13.05 TO 15.95 OHMS

AT

77°F

(25°C)

FIGURE

19.

TESTING

EXCITER

FIELD

FOR

OPENS

OR

SHORTED WINDINGS

CJI

TESTING EXCITER ROTOR

Test the exciter rotor (Figure 20) 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 CRI, CR2, CR3, CR4, CR5 and

CR6.

Test

between exciter lead pairs TI-T2,

T2-T3

and TI-T3.

Resistance should be

0.6

to

0.7

ohms at

68OF

(20°C).

Testing for Grounds

Connect leads of ohmmeter between each CR lead

and exciter rotor laminations. Usean ohmmeter set at

the highest resistance range. An ohmmeter reading

less than one megohm

(1,000,000

ohms) indicates

defective ground insulation.

TESTING GENERATOR STATOR

Using proper test equipment, check the stator for

grounds, opens, and shorts in the windings.

Testing for Grounds

Some generators have ground connections to the frame. Check

wiring diagram.

All

stator leads must be isolated

for

testing.

Use an ohmmeter set at the highest resistance range

to test each statorforshorts to laminations. A reading

less than one megohm

(1,000,000

ohms) indicates a

ground.

F2-

CR5

f

p-

CR4

CR3

WHEATSTONE

BRIDGE

CR4

*

SCHEMATIC

OF

cR6vcR'

EXCITER

A

CR2

CR5

ES-1316

FIGURE

20.

TESTING EXCITER ROTOR

..

Testing for Open or Shorted Windings

Test for continuity between coil leads shown in Fig-

ure

21;

all pairs should have equal resistance. Use an

accurate instrument for this test such as a Kelvin

Bridge. Resistance values at

77O

F (25OC) are given in

Table 2.

If any windings are shorted, open or grounded,

replace the stator assembly. Before replacing the

assembly, check the leads for broken wires or

insulation.

THREE

PHASE

MODELS

EST BETWEEN WIRE

PAIRS

Tl-T4 T7-Tl0 T3-T6

T9-Tl2' T2-T5 T8-TI1

SINGLE

PHASE

MODELS

EST BETWEEN WIRE

PAIRS

GI142

FIGURE

21.

TESTING STATOR WINDINGS

26

.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

L

,

TESTING GENERATOR ROTOR

For these tests, use an ohmmeter on the highest res-

istance range

(R

x

10 k

f2).

Models Ohms Resistance

(60

Hertz) Code 3R Code 15R

20.0 DL4 0.049

0.1

27

.

25.0 DL6 0.039 0.100

30.0 DL6 0.029 0.072

0.045

40.0DL6T

-

Testing for Grounds

On brushless type generators, check for grounds

between each rotor lead and the rotor shaft, Figure

19. Perform tests as follows:

.

1.

Remove rotor leads

Fl+

and

F2-

from rotating

rectifier assemblies.

2.

Connect ohmmeter leads between F1+ and rotor

shaft and between F2- and rotor shaft. Meter

should register one megohm or greater.

3.

If

less

than one megohm, rotor is grounded.

4.

Replace grounded rotor with new, identical part.

'

Models

(50

Hertz)

16.0 DL4

20.0 DL6

25.0 DL6

32.0 DL6T

Testing for Open or Shorted Windings

Perform tests as follows:

1.

Remove rotor leads F1+ and F2- from rotating

.

rectifier assemblies.

Ohms Resistance

Code 53R Code 515R

0.071 0.186

0.036 0.084

-

0.059

- -

\

OHMMETER

Model

50

60

Hertz Hertz

16.0 DL4 20.0 DL4

20.0 DL6 25.0 DL6

25.0 DL6 30.0 DL6

32.0 DL6T 40.0 DL6T

.

Ohms Resistance

Code Code

15R

&

515R

1.80 2.75.

2.04 1.80

.

2.32 2.04

-

2.70

3R

&

53R

W

6215

CONTACT

ONE

PROD

TO'EACH

OF

THE

FIELD

LEADS

AND

OTHER

PROD

TO

ROTOR

SHAFT.

IF

ROTOR

IS

GOOD,

THERE

WILL

BE

ONE

MEGOHM

OR GREATER

RESISTANCE.

FIGURE

22.

TESTING

ROTOR

FOR GROUNDS

2. Using ohmmeter, check resistance'between F1

and F2 leads, Figure 23.

The resistance values at

77OF

(25OC) should be as

shown in Table 3. If not, replace defective rotor

with new, identical part.

OHMMETER.

CONTACT

ONE

PROD

TO

EACH

FIELD

LEAD

8213

FIGURE

23.

TESTING

ROTOR

FOR

AN

OPEN

CIRCUIT

TABLE

3.

RESISTANCE VALUES

FOR ROTORS

WIRING HARNESS CHECK

Carefully check wiring harnesses as follows:

1.

2.

3.

4.

27

Inspect all wires for breaks, loose connections,

and reversed connections. Refer to applicable

wiring diagram.

Remove wires from terminals at each end and

using an ohmmeter, check each wire end to end

for

continuity or opens.

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.

Reconnect or replace wires according to appli-

cable wiring diagram.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

SENSITIVITY REFERENCE CIRCUIT

~

-

(Standard Voltage Regulator)

Three types of frequency sensitivity reference voltage

are possible with voltage regulator VR21.

1. Frequency sensitive-voltage output reduces in

proportion to the engine speed,

Unless otherwise requested by the purchaser, the

factory equips the set with frequency sensitive

regulation.

2.

mon-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-vol tage output de-

creases as engine speed decreases, but not as

severely as in the “frequency sensitive’’ mode.

Changing Sensitivity Reference

The sensitivity reference can be changed if neces-

sary, by unsoldering W1 on VR21 at hole

“F”

(fre-

quency sensitive) and resoldering

it

to hole

“S”

(for

semi-frequency sensitive) or to hole

“N”

(for non-

freauency sensitive) voltage regulation. See Figure

-

24.

R26

-

SENSITIVITY

REFERENCE

VRzlBOARD

USY-PC

332-1956

I

R18

VOLTAGE ADJUSTMENT

After replacement of the regulator printed circuit

board (VR21), the regulator must be adjusted for sta-

bility and voltage. Center the panel mounted voltage

adjustment knob (if equipped)

so

the pointer is in a

vertical position. Start the set and allow

it

to stabilize

at the correct frequency and speed. Adjust as speci-

fied in the following sections.

Standard Voltage Regulator

Adjust the voltage by turning R18 potentiometer on

printed circuit board VR21 counterclockwise to

decrease the voltage or clockwise to increase the

voltage. Observe thevoltmeter on control panel while

making the adjustment. Set voltage with no load con-

nected. (Example: For a 120/240 volt connection, set

no load voltage for 246 volts).

Adjust the stability (dampening) by turning R26

potentiometer on printed circuit board VR21 coun-

terclockwise until the voltage becomes unstable or

tends to hunt. Then turn R26 clockwise until the volt-

tage stabilizes.

1

Switching Voltage Regulator

Adjust the voltage by turning R36 potentiometer on

printed circuit board VR21 counterclockwise to

increase the voltage or clockwise to decrease the

voltage. Observe thevoltmeter on control panel while

making the adjustment. Set voltage with no load con-

nected. (Example: For,a 120/240 volt connection, set

no load voltage for 246 volts).

Adjust thestability (dampening) byturning

R5

poten-

tiometer on ,printed circuit board VR21 counter-

clockwise until the voltage becomes unstable or

tends to hunt. Then turn R5 clockwise until the volt-

age stabilizes.

FIGURE 24.

PC

BOARD ASSEMBLY (332-2044)

28

Redistribution or publication of this document, 

by any means, is strictly prohibited.

[QI

\

RECONNECT1

ON

.

Figure 26 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 25.

CONNECT LOOSE

WIRE

H2,

H3,

H4,

H5

OR

H6

DEPENDING

ON

VOLTAGE SELECTED

FROM

TB2-2 TO TB2-

TB2

ES-1066

FIGURE

25.

RECONNECTION LEAD

W12

TESTING

Q1

CAPACITORS

Single phase generator sets with the switching regu-

lator have two capacitors

(Ql)

mounted in the gener-

ator output box.

If

the generator set does not build up

an AC output voltage, the

Q1

capacitors should be

tested with an ohmmeter for an open condition or a

short. Make sure the capacitors are discharged

before testing.

WARNING Contact with high voltage might

a

cause serious personal injury or

death. Avoid contact with capacitor terminals. Dan-

gerous voltage might

be

present up to a minute after

set shutdown.

Place the ohmmeter on the

R

x

1

scale and touch the

test prods to the capacitor terminals. The meter poin-

ter should rise and then quickly drop back as the

capacitor becomes charged. If the pointer does not

move, the capacitor is open. If the pointer rises but

does not drop back, the capacitor

is

shorted. Replace

the capacitor

if

either condition exists.

[SI

TESTING VOLTAGE REGULATOR

The voltage regulator assembly can be removed from

the

control and tested for proper operation if neces-

sary. The following test equipment is required.

'

EQUIPMENT

Switch

5

Amp Fuse

Variable Transformer

(4

Amp, 0-280 VAC)

AC Voltmeter

(+

or

-

2%

10

VAC,

1%

250 VAC)

3

Scale DC Voltmeter,

0-1

0,

0-50,

and

0-300

(+

or

-

2% of full scale)

Resistor

-

1.65K

+

or

-

150

Ohm

Resistor

-

50

ohm, 1200 W

SCHEMATIC

*

REFERENCE

S

F

TI

VI

v2

R1

R2

29

Redistribution or publication of this document, 

by any means, is strictly prohibited.

GENERATOR

CONNECTION

SCHEMATIC

DIAGRAM

3 120/240

1

60

H5

53 110/220

1

50

H6

115/230

1

50

H6

&&Y

L2

-

CT 22

DIAGRAM

I

CT

22

60

H3

60

H5

TI~T;~

a

3

El

,2

11

T2 16111 18T12

14

19 T5

17

T3

110

11

12 13

I,

11

I

LO

W

CI

73

Y

13

11

110

16

17

12

111

14 T8 T3 112 T5 T9

12 13

W

d

-1

a

14 16

111

T2

18

T3 19

15

110

112’’

l7

T319

1

I

T39

l3

I

110111

Tl2

11

17

74 T2

18

15

98C2193

FIGURE

26.

GENERATOR VOLTAGE CONNECTIONS

30

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Standard Voltage Regulator Test

The regulator must be tested as acomplete assembly

with all components connected including thevoltage

reference transformer (T21), PC board (VR21), com-

mutating reactor (L21), and SCR bridge rectifier

(CR21).The50 ohm resistor (R2) servesas theexciter

field during testing. Use the following procedure to

check.

:

1.

Connect the test equipment to the regulator as

2. Open switch

S

and then connect

the

variable

3. Test regulator according to the steps in Table

4.

shown in Figure 27.

transformer

(Tl)

to the power supply.

V1= AC INPUT VOLTAGE

V2

=

DC OUTPUT VOLTAGE

1

Calibration Set V1 to 208 VAC Set Pot R18 to hold

V2 Between

90-1

10

VDC

2 Range A. Set

V1

to 21 1 VAC V2 shall be

<

60

VDC

V2

shall

be

<

10

VDC

3 Range A.

Set

V1

to 203 VAC V2 shall be

>

180

VDC

V2 shall be

>

140

VDC

'

Step No. Test Procedure Requirements

B.

Set

V1

to 213 VAC

B.

Set V1 to 205 VAC

EOARD

ASSY-

PC

r----

1

TB2-9

a

Tal-0

I

i

VR22

CHASSIS ASSY

Y

UGLTR

FIGURE

27.

STANDARD VOLTAGE REGULATOR

TEST SCHEMATIC

TABLE

4

STANDARD REGULATOR TEST AND CALIBRATION

31

Redistribution or publication of this document, 

by any means, is strictly prohibited.

[TI

TESTING SWITCHING

REGULATOR

The voltage regulatorassembly can be removed from

the control and tested for proper operation

if

neces-

sary.

The following test equipment is required.

EQUIPMENT

Switch

5

Amp Fuse

Variable Transformer

(4 Amp, 0-280 VAC)

AC Voltmeter

(+

or

-

2%

10

VAC, 1% 250 VAC)

3 Scale DC Voltmeter,

0-10,0-50,

and

0-300

(e

or

-

2% of full scale)

Capacitors (2)

-

400

MFD

Resistor

-

1.5

K

+

or

-

150

ohm

Resistor

-

50-80

ohm, 1200

W

Resistor

-

4700K

ohm, 2

W

Oscilloscope

-

10

MHZ

Bandwidth

J

um per Wires

SCHEMATIC

REFERENCE

S

F

TI

VI

V2-V4

c1

R1

R2

R3

01,02

W

Switching Voltage Regulator Test

The regulator must be tested separately with all com-

ponent connections removed from terminal board

TB1

.

The 50-80 ohm resistor (R2) serves as the exci-

ter field during testing. Use the following procedure

to check.

..

1.

Connect the test equipment (except jumper wires

W) to the regulator as shown in Figure 28.

2.

Open switch

S

and then connect the variable

transformer (T1

)

to the power supply.

'3.

Test regulator according to the steps in Table

5.

Terminal 8 may be used as the chassis ground

connection.

OSCILLOSCOPE

TEST PATTERN

/-\

'

\

May

be

present

I/

I'Y-

I

ES-1422

FIGURE

28.

SWITCHING VOLTAGE

REGULATOR TEST SCHEMATIC

i

32

Redistribution or publication of this document, 

by any means, is strictly prohibited.

TABLE

5

SWITCHING REGULATOR TEST

V1

=

AC

input Voltage

V2, V3, and

V4

=

DC

Output

Voltages

01

and

02

=

Oscillation Bandwidth

Step

1

2

3

4

Procedure

Set

R5

at midpoint and turn

R36 fully CCW

Set

VI

to 208 VAC

Connect jumper wires W as

shown in Figure 28

Adjust R36 fully CCW

Adjust R36 fully CW

Adjust R36 until V2 falls to10VDC

Max. Wait

5

seconds, then-proceed

to step 3.

Adjust VI to 200 VAC,

wait

5

seconds

Adjust

VI

to

210

VAC,

wait

5

seconds

Set

VI

to 208 VAC

Requirements

V2 shall be

105

-

125

VDC

V3 shall be < 2.5 VDC

01

shall be 30

-

60

microseconds

02

shall be

330

-

390 microseconds

1

V3 shall be 4.4

-

4.8 VDC

V3 shall be

7.0

-

7.8 VDC

V2 shall be

105

-

125

VDC

V2 shall be.<

10

VDC

V4 shall be

11.5

-

12.5

VDC

(Must be steady with no drift)

33

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Engine

Control

GENERAL

The engine control system includes all functions that

relate to the operation of the engine. This includes

starting and stopping, instrumentation, monitoring

for fault conditions, and battery charging. This sec-

tion covers how the engine control operates and

where the various components are located.

-.

CONTROL PANEL

The following is a brief description of the two and

'

nine light control panels with the optional AC meters.

Although the AC meters are not part of the engine

control, they are mentioned here in order to providea

complete description of the control panel exterior.

Refer to Figure

29

for the location of each

component.

Gauges/Meters and Switches

Oil

Pressure Gauge:

Indicates engine lubricating oil

pressure. The gauge has a range of

0

to

100

psi

(0

to

700

kPa).

.

Water Temperature Gauge:

Indicates engine coolant

temperature. The gauge is wired to a sensor unit on

the engine and has a range of

100'

to 25OoF,(40" to

121OC).

Battery Charge Rate DC Ammeter:

Indicates battery

charging current. Meter range is

t

30

amperes.

Running Time Meter:

Registers the total number of

hours that the unit has run. Use

it

to keep a record for

periodic servicing. Time is cumulative; meter cannot

be reset.

Frequency Meter (Optional);

Indicates generator

output frequency in hertz.

It

can be used to check

engine speed. (Each hertz equals

30

r/min.)

AC Voltmeter (Optional);

Dual range instrument

indicating AC generator voltage.

AC Ammeter(0ptional):

Dual range instrument indi-

cating AC generator line current.

Tachometer (Optional);

Indicates engine speed in

r/min. The gauge has a range of

0

to

3500

r/min.

'Oil

Temperature Gauge (Optional);

Indicates engine

oil temperature. The gauge has a range of

150"

to

300"

F

(66"

to

149"

C).

Sfarf-Stop-Remote Switch:

Starts and stops the unit

locally, or from a remote location wired to thecontrol

panel.

Pre-Heater Switch:

Provides control for glow plugs

for cold diesel engine starting.

Reset Switch:

Resets engine monitor circuits after an

emergency shutdown. On the optional control panel

the switch is also utilized to verify that the nine lamps

are functioning properly.

Phase Selector Switch (Optional);

Selects phase of

generator to be measured by AC voltmeter and

ammeter.

Voltage Adjustment (Optional):

Provides approx-

imately plus or minus

5

percent adjustment of the

rated voltage.

Circuit Breakers

FieldBreaker:

A

5

ampere breaker provides generator

protection in case of a malfunction.

Control Breaker:

A

7 ampere breaker provides pro-

tection to the control box wiring from

a

short circuit

or overload.

RemofeBreaker:

A7 ampere breaker protects acces-

sory remote controls and wiring from

a

short circuit

or overload.

..

Indicator Lights

The standard control panel has two monitor system

indicator lights.

Run (green)

.'Fault (red)

The green Run light comes on

as

soon as the starter

circuit is opened after unit starting. The red light

indicates an emergency shutdown of the generator

set.

The optional control panel has nine monitor system

indicator lights.

Run (green)

Pre Hi Eng Temp (amber)

Pre Low Oil Pres (amber)

Lo

Eng Temp (red)

Hi Eng Temp (red)

Overcrank (red)

Overspeed (red)

Lo

Oil Pres (red)

Switch Off (flashing red)

High and

Low

Indicator Lights indicate which scale to

use on the._AC voltmeter and ammeter.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

DUAL RANGE

AC VOLTMETER

FREQUENCY DUAL RANGE

METER

AC

AMMETER

1

c

INDICATOR

LAMPS

-

\

N

0

88

PAE

RESET

START

HEAT

LAUPTEST

VOLTAGE

ADJUST

RHEOSTAT

PHASE

SELECTOR

SWITCH

AMMETER/

VOLTMETER

:ALE INDlCATll

LIGHTS

......

^

/

DC

AMMETER

I

WATER

GAUGE

I

OIL

PRESSURE

GAUGE

.

TEMPERATURE

FIGURE

29.

NINE LIGHT CONTROL PANEL

WITH

OPTIONAL AC METERS

'.

CONTROL COMPONENTS

The following describes the basic engine control

components and how they function.

Engine Monitor Circuit Board:

A solid state printed

circuit board that monitors all engine control system

functions. This includes starting, stopping, and fault

system operation.

A

terminal board is included

for

making remote connections. See Figure

30.

Overcranking Timer:

A solid state circuit on the

engine monitor circuit board that limits cranking time

from

45

to

75

seconds. If the engine does not start,

cranking will stop and an oyercrank fault will be indi-

cated.

K1

Fault Relay:

Located on the engine monitor

circuit. Energized when a fault condition occurs.

Turns off the engine and prevents restarting until the

fault condition is corrected and the Reset switch is

pressed. This relay can also be used to operate a

remote DC alarm

(5

amp maximum) connected to the

fault terminal

of

the engine monitor circuit board. See

Figure

30.

K2

On/Off

Relay:

Located on the engine monitor

board. Connects battery positive

(B+)

to the electrical

circuits on the engine monitor circuit board when the

VG

SC-1302-1

Start/Stop/Remote switch is placed in the Start posi-

tion. See Figure

30.

K3

Sfarf Disconnect Relay:

Located on the engine

monitor circuit board. Energized by voltage output

from the battery charging alternator. Disconnects the

cranking circuit and turns on thegreen Run indicator

lamp when the engine starts. See Figure

30.

K1

Start Solenoid:

Located on the generator set skid

base. Connects battery positive

(B+)

to the starter

solenoid and

K2

heater solenoid when the Start/Stop/

Remote switch is placed

in

the Start position. See

Figure

31.

K2 Heater Solenoid;

Located on the generator set

skid base. Connects battery positive

(B+)

to

the glow

plugs when the Pre-heat switch

is

placed in the On

position. See Figure

31.

K3

FuelSolenoid:

An integral part of the fuel injection

.

pump. Opens the fuel control valve when the Start/

Stop/Remote switch is placed in the Start position.

-

K11

Start Disconnect Relay:

Located inside the con-

trol box. Energized by a voltage output from the gen-

erator. Disconnects the cranking circuit when the

engine starts. See Figure

30.

35

Redistribution or publication of this document, 

by any means, is strictly prohibited.

K21

VOLTAGE

K12

START

RUN

SC-1313

.

K3

START

DISCONNECT

RELAY

K2

ON/OFF

RELAY

K1

FAULT

RELAY

ENGINE

MONITOR

'

CIRCUIT

BOARD

/

REMOTE

PREHEAT

SWITCH

,

NINE

LIGHT-

TERMINAL

BOARD

REMOTE

FAULT

ALARM

I

REMOTE

1

II

REMOTE LIGHTS

---

.OP

OC

OS

HE7

LET

PLOP

SWOFF

GND

ICRANK

I

T

irnVlC

e+

IPRAHEAT

-

REM~TE

LO~IL

OV~R-

LO.BNG.

START PRESS. SPEED

TEN

FIGURE

30.

CONTROL

BOX

INTERIOR

'

K72 Run

Relay (Optional):

Located inside the control

box. Used with warning alarm to indicate when the

generator set starts. Energized when the

K3

start dis-

connect relay connects battery positive

(B+)

to the

K27

Voltage Scale Relay:

Located inside the control

terminal shown in Figure

30.

Current limitations for

optional equipment not supplied by

ONAN

are

100

milli-amperes for each indicator lamp and

5

amperes

for the fault alarm.

green Run indicator lamp.

.

..

box. Used to operate the scale indicator lights.

ENGINE

SENSORS

The following briefly describes the enaine mounted

'

Control components can be dam-

.

aged if these current limits are

exceeded

for

the optional equipment.

sensors and switches, and how they protect the

engine from unfavorable operating conditions.

.

All cut-off switches close to ground if abnormal oper-

ating conditions exist and energize the Fault Relay to

stop the engine. The respective control panel lamps

(optional) light to indicatecause of theshutdown. An

optional remote fault alarm can be connected to the

Resistance units and switches in the monitoring and

shutdown systems are sealed units and not repair-

able. When replacing asensor, do not use a substitute

item since resistance units are matched to the gauge

they Supply. Cutoff switches are close tolerance,

Parts made for a specific application.

'3'6

.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

PRE

-AND

K2

HEATER

SOLENOID

*'..,

e..

'%,,

'e...

K1

START SOLENOID

"...,

*..

e...

e..

*....

*..*

*...

'e...

e...

'%..

'e...

"...

%..

*...

ES-1312

FIGURE

31.

ENGINE CONTROL RELAYS AND SENSORS

Oil Pressure Monitors

Refer to Figure

31

for the location of the oil pressure

.

sensors.

The oil pressure sender resistance changes with oil

pressure and results

in

a reading on the oil pressure

meter. The meter range is

0

to

100

psi

(0

to

700

kPa).

The low oil pressure switch closes if pressure drops

to

14

psi

(97

kPa), stopping the engine and activating

,

the optional low oil pressure fault lamp.

The optional pre-low oil pressure switch closes at 20

psi

(138

kPa) and turns on the amber Pre

Lo

Oil Pres

lamp. The engine does not shut down, but the warn-

ing lamp remains on until the Resetswitch is pressed.

Engine Temperature Monitors

Refer to Figure 32 for the location of the engine

tern peratu re sensors.

LOW

OIL

1

LOW

OIL

PRESSURE

The resistance of the temperature sender unit

changes with the engine coolant temperature and

causes

a

reading on the Water Temp meter. The

.meter range is

100'

to 250'

F

(40'

to 121

O

C).

The high engine temperatureswitch closes if the cool-

ant temperature rises to 222OF (106'C), stopping the

engine and activating the red

Hi

Eng Temp light.

The optional pre-high engine temperature switch

closes at a nominal 216°F (102OC) and turns on the

amber Pre/Hi Eng Temp lamp. The engine does not

shut down, but the warning lamp remains

on

until the

Reset switch is pressed.

The optional low engine temperature switches closes

if coolant temperature drops below

70'F

(21OC) to

turn on the red

Lo

Eng Temp

light.

37

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by any means, is strictly prohibited.

PRE

HI

ENGINE TEMP

LO

ENGINETEM+

HI

ENGINE TEMP

I

..r

ES-1313

.,?

'*.

FIGURE

32.

ENGINE TEMPERATURE SENSORS

Overspeed Switch

The overspeed switch is a mechanical switch which

grounds the overspeed circuit on the Engine Monitor

Circuit Board if an overspeed condition exists caus-

ing an engine shutdown and activating the optional

overspeed fault lamp. After the problem is corrected,

starting will not occur until the Reset switch is

pressed.

GENERATOR

v

FIGURE

33.

OVERSPEED

SWITCH

The overspeed switch is set

so

contacts close at 2200

to 2250 rpm. If necessary, the speed range can be

corrected by turning the adjusting screw, thereby

changing the magnetic air gap (see Figure 33). The

air gap must not be less than

0.005

inch (0.13 mm).

OPERATION

Dependable, trouble-free operation of the control

system should be the major concern of generator set

service personnel. Service personnel 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.

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.

Figure 34 shows a typical wiring diagram for the cir-

cuits described

in

the following Starting, Start-

Disconnect and Stopping sequences. Relay contact

references normally open

(NO)

and normally closed

(NC)

refer to position of contacts with the unit at rest

(not energized).

Starting Sequence

For cold engine starjing,

the

Preheat switch (Sll) is

held

in

the preheat position for 10 seconds. This

energizesthe K2 heater solenoid which closes a set of

NO

contacts that connect B+ to the glow plugs. At the

end of the preheat period, the starting sequence is

initiated by placing the Start/Stop/Remote switch

(S10) hthe Start position.

..

Placing switch S10

in

the Start position energizes the

K2 On/Off relay which closes a set of

NO

contacts.

Closing K2 contacts connects B+ to the electrical

circuits on the engine monitor board, the K1 start

solenoid, and the K3 fuel solenoid.

Energizing the K1 start solenoid closes two sets of

NO

contacts that connect

B+

to the starter solenoid

and K2 heater solenoid. Energizing the starter sole-

noid initiates cranking. Energizing the K2 heater

solenoid continues (initiates) operation

of

the glow

The K3 fuel solenoid opens the fuel control when

energized.This solenoid is an integral part of the fuel

injection pump.

plugs.

Start-Disconnect Sequence

When the generator set starts, output voltage from

the auxiliary terminal of the DC alternator energizes

the K3 start-disconnect relay. Energizing K3 start-

disconnect relay closes one set of

NO

contacts and

opens another set of

NC

contacts. Closing the

NO

set

Of

K3 contacts connects B+ to the run lamp. Opening

ES-1298-1

3'8

Redistribution or publication of this document, 

by any means, is strictly prohibited.

s10

512

s11

CIRCUIT

BREAKERS

M

AMMETER

u

FAULT

RELAY

I

ALTERNATOR

I

47TLil

TIMER

OVERSPEEI

SWITCH

TIMER

F-

LOW

OIL

'

PRESS.

I

SWITCH

I

FUEL SOLENOID

--

TB5-9

FIGURE

34.

TYPICAL WIRING DIAGRAM

:

39

PANEL

LIGHTS

ES-1314

Redistribution or publication of this document, 

by any means, is strictly prohibited.

the

NC

set of

K3

contacts disconnects

B+

from the

K1

,

start solenoid. De-energizing the

K1

start solenoid

disconnects

B+

from the starter solenoid to stop

cranking and also disconnects B+from the

K2

heater

solenoid to stop preheating.

A

back-up start disconnect relay

is

used to stop

cranking. When the generator set starts, output volt-

age from the generator stator energizes the

K11

start

disconnect relay. Energizing

the

K11

start disconnect

relay opens a set of NC contacts. Opening the

NC

set

of

K11

contacts disconnects

B+

from the

K1

start

solenoid. De-energizing the

K1

start solenoid

dis-

connects

B+

from the starter solenoid to stop crank-

ing

and also disconnects

B+

from the

K2

heater sole-

noid to stop preheating.

Stopping Sequence

Placing the

S10

Start/Stop/Remote switch

in

the Stop

position disconnects

B+

from the

K2

on/off relay.

De-energizing

K2

on/off relay disconnects

B+

from

the

K3

fuel solenoid and the electrical circuits on the

engine monitor board. De-energizing the

K3

fuel

solenoid

shuts

off the fuel flow which stops the

engine.

Emergency Shutdown

The

K1

fault relay

is

energized when fault sensors

respond to one of'the following fault conditions:

overcrank, low oil pressure,

high

engine temperature,

and overspeed.

Energizing the

K1

fault'relay .opens one

set

of

NC

contacts and closes two sets of

NO

contacts. Open-

ing

the

NC

set of

K1

contacts disconnects

B+

from the

K1

start solenoid andthe

K3

fuel solenoid. This stops

cranking

if

the engine

is

being cranked and

shuts

off

the fuel flow. Closing one of the

NO

sets of

K1

con-

tacts grounds the

K1

fault relay

so

that the

K1

relay

cannot be de-energized

until

the

S12

reset switch

is

momentarily opened. Closing the other

NO

set of

K1

contacts connects

B+

to the remote alarm terminal.

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

LOP shutdown and pre-alarm are functional. Follow-

ing

this initial delay, both the

LOP

shutdown and

pre-alarm functions are immediate.

40

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by any means, is strictly prohibited.

Engine Control Troubleshooting

Is

battery dead? yes+

GENERAL

The information

in

this section is divided into three

flow charts. Determine the problem and then refer to

the appropriate flow chart (A,

B,

or C) for the trouble-

shooting procedures.

Check battery per Checkout

[A]

and recharge

'

or replace. Check alternator operation per

A. Engine does not crank.

B.

Engine cranks but does not start.

C. Engine starts but stops after running several

seconds.

With S10 in Start position, doesstart solenoid K1

'

!

energize?

(Is

at least

7

volts DC present between

I

K1 terminal

S

and ground?)

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

Check K1 start solenoid, K2 on/off. relay,

K3

and K11 start

-no+ disconnect relays,

SI0

switch, and all connections.. See

Checkouts

D,E,

and

G.

performed since last satisfactory operation of set.

A loose wire connection overlooked when install-

ing 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 absolutelysurethat panel instrumentsare

accurate, use portable test meters for trouble-

shooting.

To

troubleshoot a problem, start at the upper-left

corner of chart and answer all questions eitherYES or

NO.

Follow the chart until the problem is found, per-

forming referenced adjustment or test procedures.

Refer to typical wiring diagram in Figure

29

for locat-

ing control component leads, terminals and other

check points.

Is

at least

7

volts DC present between

B1

starter

solenoid terminal and ground? SCheck wiring and connections between K1 terminal

I

and the solenoid terminal B1.

no

1

Check for possible fault conditions.

If ok, check K1 fault relay per Checkout

E.

Is

the K1 fault relay energized?. yes

4

Check battery cables for clean and tight connections

(ref. Checkout [B]). Check B1 starter solenoid and

motor

-

if

bad, repair

or

replace.

Jumper battery cable B+ connection to B1 starter

solenoid terminal. Does engine crank?

I

1

2

I

41

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by any means, is strictly prohibited.

FLOW CHART

B.

ENGINE CRANKS BUT DOES NOT START

..

Does K3 fuel solenoid energize when

S10

is in Start position.

---no-

Check K3 fuel solenoid (Test

F)

and related wiring.

yis

1

Is preheat system operating properly?

-

7

Check fuel supply system: fuel tank, shutoff valves, fuel

lines and connections, fuel filters and transfer pump.

’

Is

engine getting fuel? (Exhaust smoke should be

blue-white, and fuel flow steady from fuel return

line.)

Check heater solenoid K2 and switch

SI1

per Checkouts

[D] and

[GI.

Check wiring and heater elements.

1

I

Check for possible fault condition., If

OK,

check

S1

engine

Is a fault condition indicated by

:

-yes--, temp. switch,

S6

overspeed switch, and S3 oil pressure

switch. Check

K1

fault relay for short to ground.

panel light?

-

~

Connect voltmeter between stop terminal

of

S10

and ground. Is battery

voltage read as

RPM

increases?

yis

1

~ ~ ~~

~~ ~~

,

Check switch

S10

and related wiring

’

for open circuit or short to

ground.

-no----)

I

A

Incorrect fuel? (See Operator’s Manual

recommendations.)

Jump normally open contacts of K2

on/off relay. Does engine start and run? no-

I

:

Replace

A

11

engine monitor circuit board.

FLOW CHART C. ENGINE STARTS BUT STOPS AFTER RUNNING SEVERAL SECONDS

START

I

no

‘I

ye5

I

Replace K2 on/off relay

I

42

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by any means, is strictly prohibited.

Engine

'Control

AdjustrnentdTests

GENERAL

ually tapering to zero as the battery becomes fully

chaiged. If the ammeter shows a constant discharge

or a constant high rate of charge, stop the generator

set

and

check

for

a

loose

or

slipping

drive

belt,

poor

terminal connections, or broken lead wires. Repair or

replace as required.

The following component checkouts are referenced

in the Control Troubleshooting flow charts. They are

an aid to isolating circuit problems caused by faulty

engine control components.

All external engine control components such as

leads, switches, relays, indicator lights, senders, and

gauges plug into the engine monitor board. When

testing external components, disconnect the corres-

ponding jack

(JI,

J2, or

J3)

from the board. Refer to

the appropriate wiring diagram to determine the jack

number.

If everything checks out, use

a

voltmeterto determine

the alternator output voltage. Connect the positive

(+)

lead to the output terminal (see Figure 35) and

connect the negative

(-)

lead to ground. Start the

generator set and run for a few minutes to allow the

.

voltage to stabilize.

A

properly operating system will

have a nominal output voltage of between 13.8 and.

14.8 volts.

TAl

BATTERY CHECKOUT

Check charge condition

of

the battery with a hydro-

meter. The electrolyte specific gravity should be

about 1.260forafullycharged battery at8OoF (27°C).

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 alternator

'

charge rate may be too high. Likewise,

if

battery state

of charge is not maintained, the charge rate may be

too low. Refer to ALTERNATOR CHECKOUT

[C].

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.Thoroughly clean all

connections in any part

of

the circuit showing exces-

sive voltage drop.

ALTERNATOR CHECKOUT

With the engine running, check the battery charge

rate

DC

ammeter.

If

the alternator is operating prop-

erly, the ammeter should show a slight charge, grad-

..

A.

AUXILIARY

MOTOROLA

D

TO

TERMINAL

26

ES-1319

FIGURE

35.

ALTERNATOR

If the output voltage is high (over

15

volts), check for

loose or corroded voltage regulator leads. If this does

not correct the problem, the regulator is probably

shorted and should be replaced.

4.3

Redistribution or publication of this document, 

by any means, is strictly prohibited.

If

the output voltage is low (equals battery voltage),

the problem could be worn or broken brushes, an

open regulator, or an open field diode. Refer to

Motorola Service Manual 25-183 for more detailed

test and service procedures.

SOLENOID CHECKOUT

1. Apply battery positive

(B+)

to the terminal

marked

S.

2. Jumper a ground wire to the solenoid mounting

bracket. Solenoid should activate.

3.

If the contacts are good, 12 volts should be read

between terminal

I

and ground. The voltage drop

measured across the contacts should never

exceed one volt in circuit application.

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

12 volts appear when relay

energized, contact is okay. The 12-volt reading

appears in reverse order when checking normally

closed (NC) contacts.

FUEL SOLENOID CHECKOUT

If there is fuel to the injection pump, but no fuel at

injection nozzle, the fuel solenoid may be defective.

To check energized-to-run fuel solenoid operation,

listen for a click

in

injection pump when start switch is

placed

in

the run position. If no click is heard and

there is power to solenoid with the start switch in the

run position, the fuel solenoid must be replaced.

To

check energized-to-stop fuel solenoid operation,

listen for a click

in

injection pump when start switch is

placed in the stop position. If no click is heard and

there is no power to solenoid with the start switch in

the stop position, the fuel solenoid must be replaced.

Refer to the

L

Engine Service Manual

(934-0750)

for

,

fuel solenoid replacement procedures.

SWITCH CHECKOUT

1.

Remove battery

B+

cable.

2.. Place ohmmeter leads across switch.

3. Open and close switch while observing the ohm-

meter.

A

normally open

(NO)

switch should indi-

cate infinite resistance when open and continuity

when closed.

A

normally closed

(NC)

switch

should indicate continuity when closed and infi-

nite resistance when open.

4. Replace switch if defective.

44

Redistribution or publication of this document, 

by any means, is strictly prohibited.

.

Wiring

Diagrams

"

The electrical schematics and wiring diagrams that apply to the DL series generator sets are listed below.

FIGURE 36.

Single Phase AC Control with Optional Meters (612-6022).

FIGURE 37.

Three Phase AC Control with Optional Meters (612-6023).

FIGURE 38.

Single and Three Phase AC Control (612-6024).

FIGURE 39.

Single Phase AC Control with Switching Regulator and Optional Meters (612-6075).

FIGURE 40.

Three Phase AC Control with Switching Regulator and Optional (612-6076).

.

FIGURE 41.

Single and Three Phase AC Control with Switching Regulator (612-6077).

FIGURE

42.

Standard Voltage Regulator Assembly (305-0693).

FIGURE 43.

Switching Voltage Regulator Assembly (305-0695).

FIGURE 44.

Two Light DC Control Wiring Diagram (612-6020).

FIGURE 45.

Two Light DC Control Schematic (612-6020).

FIGURE 46.

Nine Light DC Control Wiring Diagram (612-6021).

FIGURE 47.

Nine Light DC Control Schematic (300-2510).

FIGURE 48.

Two Light Engine Monitor Board Schematic (300-2510).

FIGURE 49.

Two Light Engine Monitor Board.

FIGURE

50.

Nine Light Engine Monitor Board Schematic (300-2453).

FIGURE

51.

Nine Light Engine Monitor Board.

.

'

45

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8

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FIGURE

41.

SINGLE AND THREE PHASE AC CONTROL

51

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n

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FIGURE

42

VOLTAGE REGULAT0,R ASSEMBLY

52

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,

.P

P

Po

NOTE

:

TRANSFORMER

CONNECTION

(711)

A.

X,

TO VRI-IO

6.

X,

TO

VRI-9

13

12

IO

9

8

1

!!-

b

5

-

4

3

2

I

6

8

2

4

I

2

-

RESISTOR ASSY

-01

HARNESS

-

WIRING

RERCTOR ASSY

-

COMM

TERMINAL BLOCK

(78.2)

-.

MARKER STRIP

TRRNSFORMER

-

VOLT

(TI1

)

SCREW

-

RHM

1

b-32

X

3/81

NUT-HH

ET

(6-32)

SCREW

-

RHM

(

L-32

X

S/8)

WASHER

-

ET

LK

("L)

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Cummins DL4 DL5 DL6T Generator Service Manual

900-0336 Onan DL4 DL6 DL6T Genset Generator & Controls Service manual (08-1983) 900-0336 Onan DL4 DL6 DL6T Genset Generator & Controls Service manual (08-1983)

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