Service Handbook Matsushita DA51C72RCU6 Compressor

User Manual: Matsushita DA51C72RCU6

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A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
15
2
3
COMPRESSOR MOTOR
AND COMPONENT
INFORMATION
I. Single Phase Compressor Motor Types . 16
II. PSC Motor Starting . . . . . . . . . . . . . . . . . 18
III. Hermetic Compressor Thermal
Protectors . . . . . . . . . . . . . . . . . . . . . . . . 19
IV. Compressor Motor Starting Relays . . . . . 27
V. Selecting Capacitors . . . . . . . . . . . . . . . . 32
VI. Identification of Terminal Pins . . . . . . . . . 34
VII. Fuse and Circuit Breaker Sizing . . . . . . . 36
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16
Chapter 3
I. Single Phase Compressor
Motor Types
Tecumseh hermetic compressors contain motors
designed for specific requirements of starting torque
and running efficiency. There are four general types
of single phase motors, each distinctly different from
the others. Each type of motor may have two to four
different configurations depending on the compres-
sor components.
A. Resistance Start—Induction Run (RSIR)
This motor, also known as a split-phase motor, is
used on many small hermetic compressors up
through 1/3 HP. The motor has low starting torque
and must be applied to completely self-equalizing
capillary tube systems such as household refrigera-
tors, freezers, small water coolers, and dehumidifi-
ers. This motor has a high resistance start winding
which is not designed to remain in the circuit after
the motor has come up to speed. A relay is necessary
to perform the function of disconnecting the start
winding as the motor comes up to design speed.
Three types of relays are used with this motor:
•a current relay,
•a wired-in Positive Temperature Coefficient
(PTC) relay, or
•a module Positive Temperature Coefficient
(PTC).
B. Capacitor Start—Induction Run (CSIR)
The CSIR motor is similar to RSIR except a start
capacitor is included in series with start winding to
produce a higher starting torque. This is commonly
used on commercial refrigeration systems through
3/4 HP. Two types of relays are used with this
motor:
•a current relay, or
•a potential relay.
Figure 3-1.
RSIR motor diagram with current relay.
Line 1
Line 2
Ground
Control
Relay - Current
External Thermal
Protector
Start Winding
Main Winding
Compressor - Unit
Ground
C
S
R
Figure 3-2.
RSIR motor diagram with wired-in
PTC relay.
4 T M Thermal Protector
Identified Conductor
(115 Volt Only - Neutral)
Line 1
Line 2
Ground
Start Winding
Main Winding
PTC Relay
Compressor - Unit
Ground
Alt. 3/4" Thermal Protector
Control
C
S
R
Figure 3-3.
CSIR motor diagram.
Line 1
Line 2
Ground
Control
Relay - Current
External Thermal
Protector
Start Winding
Main Winding
Compressor - Unit
Ground
S
R
C
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
17
C. Capacitor Start and Run (CSR)
This motor arrangement uses a start capacitor and a
run capacitor in parallel with each other and in
series with the motor start winding. This motor has
high starting torque, runs efficiently, and is used on
many refrigeration and air conditioning applications
through 5 HP. A potential relay removes the start
capacitor from the circuit after the motor is up to
speed. This motor may use either:
•an external thermal protector, or
•an internal thermal protector.
D. Permanent Split Capacitor (PSC)
Here a run capacitor is in series with the start wind-
ing. Both run capacitor and start winding remain in
the circuit during start and after motor is up to
speed. This normal starting torque motor is suffi-
cient for capillary and other self-equalizing systems.
No start capacitor or relay is necessary. For addi-
tional starting torque, a proper start assist kit may be
added (see Figure 3-6). Some start assist kits may
include:
•a wired-in Positive Temperature Coefficient
(PTC) relay, or
•a module Positive Temperature Coefficient
(PTC) relay.
This motor may use either:
•an external thermal protector, or
•an internal thermal protector.
PSC motors are basically air conditioning compres-
sor motors and are very common up through 5 HP.
Figure 3-4.
CSR motor diagram.
Relay -
Potential
Compressor -
Unit Ground
Line 1
Line 2
Ground
Start Winding
Main Winding
Control
External or Internal
Thermal Protector
C
S
R
Figure 3-5.
PSC motor diagram.
Compressor -
Unit Ground
External or Internal
Thermal Protector
Run Capacitor
Line 1
Line 2
Ground
Start Winding
Main Winding
Control C
S
R
Figure 3-6.
PSC motor diagram with start assist kit
that includes a module PTC relay.
Line 1
Line 2
Ground
Compressor -
Unit Ground
PTC
Relay
Plug-In
Run Capacitor
PTC Starting and
Protector Package
Thermal Protector
Start Winding
Main Winding
C
C
C2
C1
N
S
R
18
Chapter 3
II. PSC Motor Starting
Tecumseh Products Company has pioneered in
encouraging the development of Permanent Split
Capacitor compressor motors. This type of motor
eliminates the need for potentially troublesome and
costly extra electrical components (start capacitors
and potential motor starting relays). (See Figure
Figure 3-7.)
To fully realize the capabilities of this simplified type
of compressor motor, it is necessary to understand
its starting and operating characteristics and the
field conditions which can affect it.
The following conditions affect PSC motor starting:
•Low voltage: Reduces motor starting and run-
ning torque. A 10% voltage drop reduces a
motor’s starting ability by 19%. Low voltage
can cause no start, hard start, light flicker, and
TV screen flip flop.
Minimum starting voltage for the compressor
when it is attempting to start (locked rotor) is:
•Unequalized system pressure: Head and suc-
tion pressures must be equal and not more than
170 psig. Refrigeration metering device (cap
tube or TX valve) should equalize system pres-
sures within 3 minutes. Unequal system pres-
sure may be caused by excessive refrigerant
charge, short cycling thermostat, or system
restriction.
•Circuit breaker or fuse trips: Branch circuit
fuses or circuit breakers sized too small will
cause nuisance tripping (see “Fuse and Circuit
Breaker Sizing” on page 36). If the fuse or cir-
cuit breaker trips, see “Identifying Compressor
Electrical Problems” on page 47 for electrical
troubleshooting techniques.
•Electrical components: A failed run capacitor
will not allow the compressor to start, and it
will trip the thermal protector. See “Identifying
Compressor Electrical Problems” on page 47
for electrical troubleshooting techniques.
Figure 3-7.
Circuit diagram for PSC compressors.
Compressor -
Unit Ground
External or Internal
Thermal Protector
Run Capacitor
Line 1
Line 2
Ground
Start Winding
Main Winding
Control C
S
R
Table 3-7: Minimum Starting Voltage
Serial Label Voltage Min. Voltage for Start
115 103
208 188
230 207
230/208 198
265 239
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
19
III. Hermetic Compressor Thermal
Protectors
Hermetic compressor motors are protected from
overheating by thermal protectors built into or
mounted in contact with the compressor motor. See
the Electrical Service Parts Guide Book for correct
replacement thermal protectors. Typical wiring dia-
grams are shown on pages 51 to 82.
The thermal protector device (see Figure 3-8), when
firmly attached to the compressor housing, quickly
senses any unusual temperature rise or excess current
draw. The bi-metal disc within the thermal protec-
tor (see Figure 3-9) reacts to either excess tempera-
ture and/or excess current draw by flexing
downward, and disconnecting the compressor from
the power source.
Figure 3-8.
External thermal protector. (Models AE,
TP, TH, AK, AJ, CAJ, AZ, RK, RG, TW,
and some CL.)
Figure 3-9.
Bi-metal disc.
Open Closed
Figure 3-10.
AE refrigeration compressor
showing (1) hermetic terminal,
(2) thermal protector, (3) thermal
protector clip, (4) push-on relay,
(5) protective terminal cover, and
(6) bale strap.
Figure 3-11.
AE refrigeration compressor with
the thermal protector and relay
assembled.
20
Chapter 3
A. Internal Thermal Protectors
Internal thermal protectors are completely internal
and tamper-proof. They cannot be by-passed.
Single Phase Motor Thermal Protectors
Internal thermal protectors detect excess heat and/or
current draw. They are located in the following sin-
gle phase motors: AB, AW, AH, AV, and AG.
3-Phase Motor Thermal Protectors
The 31HM and 32HM on-winding motor protec-
tors are 3-phase line break, automatic reset devices
wired in series with each phase at the neutral point
and mounted on the windings. They are used in AB,
AG, AV, and AN models.
Table 3-2: Facts About Thermal Protectors
External Line-Break Thermal
Protectors
•Currently used on all AE, AK, AZ, RK, and AJ models
•Sense motor current and housing temperature or combination
thereof
•Break line current when tripped
•Generally do not protect against loss of charge
•When, by design, no air flow passes over housing, a special
“static” thermal protector must be used
•Are designed for specific compressors and their intended
application. Make no substitutions
•Will not protect motor if compressor is operated outside its
evaporator temperature range
Internal Line-Break Thermal
Protectors
•Currently used on all AH, AB, AV, AG, AW, and most AN and SF
models
•Sense motor current and motor winding temperature or
combination thereof
•Break line current when tripped
•Generally protect against loss of charge
•Will not protect motor if compressor is operated outside its
evaporator temperature range
•Not repairable or replaceable
Line Voltage-Electronic Protection
Module
(NOTE: For more specific details
consult the authorized wholesaler.)
•Currently used on some AN and SF models
•Employs use of solid state temperature sensors in motor
windings and compressor discharge muffler
•Sensor resistance values change with temperature variations
•Module will interrupt power to the contactor coil when resistance
values of sensors exceed the specified range. This power
interruption thus stops the compressor motor
•Module provides protection against:
•Abnormal locked rotor conditions
•Loss of refrigerant
•High compressor discharge temperatures
•Excessive current conditions
•Time delays of 3 to 5 minutes occur on power interruption or
sensor trip
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
21
B. “AN” Wiring on Typical 230/200 Volt
System with Electronic Protection
Module
The Model AN compressors are available with an
advanced solid state protection system. Sensors are
provided in each leg of the compressor motor wind-
ings to guard against overloading and single phasing.
Additionally, a sensor is in the internal discharge line
to detect excessive discharge gas temperatures.
Notes on the compressor electronic protection sys-
tem:
•The compressor will not run if a jumper is
placed across terminals S and S1.
•Terminals M1 and M2 are a normally closed
switch actuated by the motor sensor circuit.
Switch contacts are rated at 2.5 amps at 265
volts maximum.
•Do not expose the protection module to pro-
longed ambient temperature higher then
150°F.
•Module has built-in time delay. Power inter-
ruption or sensor trip will cause 3 to 5 minute
delay before restart.
•If sensor circuit trips and motor feels cool,
check the return gas temperature. It should not
be more than 65°F entering the compressor.
22
Chapter 3
B. “AN” Wiring on Typical 230/200 Volt System with Electronic Protection Module - Continued
2 Speed Motor
Connections
Line Voltage
C'Case Heaters
T
1
T
2
T
3
L
1
L
2
L
3
Contactor
230/200-60-3
# 14 Min.
# 14 Min.
# 14 Min.
See Table 3-3
Use Copper Conductors Only
24 Volt
Compressor
Sensors Compressor
Power
To
Control
Circuit
Contactor
Coil
S
1
C
1
L
1
L
2
L
3
R
1
R
2
R
3
C
2
S
Table 3-3: "AN" Wiring on Typical System
Model
AN5590E/F
AN5610E/F
AN5612E/F
AN5614E/F
#8 TW
#8 TW
#6 TW
#6 TW
92,500
100,000
122,000
140,000
27
29
36
42
172
183
229
269
RLA LRA
Capacity
BTU/HR
Min.
Cond.
Size
M
1
T
1
M
2
SS
1
T
2
Control Line
15AA1104C
Electronic Protection Module
Figure 3-12.
“AN” wiring on typical 230/200 volt system with electronic protection module.
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
23
C. “AN” Wiring on Typical 460 Volt System with Electronic Protection Module
2 Speed Motor
Connections
Line Voltage
C'Case Heaters
T1T2T3
L1
M1T1
M2
SS
1
T2
L2L3
*Contactor
460-60-3
# 14 Min. Transformer
460V Input 230V Output
230V 460V
Run New Lead From M1
To Contactor Coil
Remove Existing Lead At
Contactor Coil And Connect To M2# 14 Min.
See Table 3-4
Use Copper Conductors Only
24 Volt
Compressor
Sensors Compressor
Power
To
Control
Circuit
Control Line
230V
15AA1104C
Electronic Protection Module
S1C1L1L2L3R1R2R3
C2
S
Table 3-4: "AN" Wiring on Typical 460 Volt System
Model
AN5590E/F
AN5610E/F
AN5612E/F
AN5614E/F
#12 TW
#12 TW
#10 TW
#10 TW
92,500
100,000
122,000
140,000
14
14.5
18
21
86
93
116
135
RLA LRA
Capacity
BTU/HR
20 A
20 A
25 A
30 A
Min.
Cont.*
Size
Min.
Cond.
Size
*Contactor ampere rating is at compressor rated voltage.
# 14 Min.
Figure 3-13.
“AN” wiring on typical 460 volt system with electronic protection module.
24
Chapter 3
D. “AN” Wiring on Typical System with Thermal Protector
Figure 3-14.
“AN” wiring on typical system with thermal protector.
2 Speed Motor
Connections
T
1
T
2
T
3
L
1
L
2
L
3
Contactor
To Line
# 14 Min.
See Table 3-5
Compressor
Power
To
Control
Circuit
C
1
L
1
L
2
L
3
R
1
R
2
R
3
C
2
Table 3-5: "AN" Wiring on Typical System
with Thermal Protector
Model
AN5590G/H
AN5610G/H
AN5612G/H
AN5614G/H
AN5590G/H
AN5610G/H
AN5612G/H
AN5614G/H
230/200-60-3
230/200-60-3
230/200-60-3
230/200-60-3
460-60-3
460-60-3
460-60-3
460-60-3
#8 TW
#8 TW
#8 TW
#6 TW
#12 TW
#12 TW
#10 TW
#10 TW
92,500
100,000
122,000
140,000
92,500
100,000
122,000
140,000
27
29
36
42
14
14.4
18
20.8
172
183
229
269
86
93.3
116
135
RLA LRA
Capacity
BTU/HR
Min.
Cond.
Size
Voltage
40 A
40 A
50 A
60 A
25 A
25 A
25 A
30 A
Min.
Cont.*
Size
Not Used On
Internal Line Break
Models (G & H Suffix)
Use Copper Conductors Only
24 Volt
Compressor
Sensors
S
1
S
*Contactor ampere rating is at compressor rated voltage.
Line Voltage
C'Case Heaters
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
25
E. Small Terminal Block with Thermal Protector
Figure 3-15.
Small terminal block wiring on typical system with thermal protector.
T1T2T3
L1L2L3
Crankcase Heaters
To Control Circuit
Clear Tie Compressor Terminal Fence
Contactor
Black Tie
Ground
3 Ph. Incoming Power
26
Chapter 3
F. Small Terminal Block with Electronic Protection Module
Figure 3-16.
Small terminal block wiring on typical system with electronic protection module.
T2T3
L1L2L3
To Control Circuit
24 or 120 or 240 V.A.C.
Single Phase
Clear
Tie Compressor Terminal Fence
Contactor Coil
Contactor
Black Tie
Ground
T1
M1T1
M2
S1S2
T2
To Protection
Module Line Circuit
Electronic Protection Module
15AA1104 (See Table 3-6)
Control Line
2.5A. Max.
24/115/230 V.A.C.
3 PH. Incoming Power
Texas
Instruments
Parts
Number
15AA1104A
15AA1104B
15AA1104C
90613
90613-2
90613-1
24 V.A.C.
115 V.A.C.
208 or 230 V.A.C.
Line
Circuit
T1, T2,
V.A.C.,
1-PH
Tecumseh
Part
Number
24 or 115 or 230 V.A.C.
24 or 115 or 230 V.A.C.
24 or 115 or 230 V.A.C.
Control Circuit
M1, M2,
V.A.C., 1-PH
Table 3-6: Small Terminal Block Information
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
27
IV. Compressor Motor Starting
Relays
A hermetic motor starting relay is an automatic
switching device to disconnect the motor start
capacitor and/or start winding after the motor has
reached running speed.
Never select a replacement relay solely by horse-
power or other generalized rating. Select the correct
relay from the Tecumseh Electrical Service Parts
Guide Book.
There are two types of motor starting relays used in
refrigeration and air conditioning applications: the
current responsive type and the potential (voltage)
responsive type.
A. Current Type Relay
When power is applied to a compressor motor, the
relay solenoid coil attracts the relay armature
upward causing bridging contact and stationary
contact to engage. This energizes the motor start
winding. When the compressor motor attains run-
ning speed, the motor main winding current is such
that the relay solenoid coil de-energizes allowing the
relay contacts to drop open thereby disconnecting
motor start winding.
The relay must be mounted in true vertical position
so armature and bridging contact will drop free
when relay solenoid is de-energized.
B. PTC Type Relay
Solid state technology has made available another
type of current sensitive relay—a PTC starting
switch. Certain ceramic materials have the unique
property of greatly increasing their resistance as they
heat up from current passing through them. A PTC
solid state starting device is placed in series with the
start winding and normally has a very low resistance.
Upon startup, as current starts to flow to the start
winding, the resistance rapidly rises to a very high
value thus reducing the start winding current to a
trickle and effectively taking that winding out of
operation.
Usage is generally limited to domestic refrigeration
and freezers. Because it takes 3 to 10 minutes to cool
down between operating cycles, it is not feasible for
short cycling commercial applications.
C. Potential Type Relay
Generally used with large commercial and air condi-
tioning compressors (capacitor start, capacitor run)
to 5 HP. Relay contacts are normally closed. The
relay coil is wired across the start winding and senses
voltage change. Starting winding voltage increases
with motor speed. As the voltage increases to the
specific pickup value, the armature pulls up, open-
ing the relay contacts, de-energizing the start wind-
ing capacitor. After switching, there is still sufficient
voltage induced in the start winding to keep the
Figure 3-17.
Current type relay.
Figure 3-18.
PTC type relay.
28
Chapter 3
relay coil energized and the relay starting contacts
open. When power is shut off to the motor, the volt-
age drops to zero, the coil is de-energized, and the
start contacts reset.
When changing a compressor relay, care should be
taken to install the replacement in the same position
as the original.
Figure 3-19.
Potential type relay.
Table 3-7: Facts About Starting Relays
Relay Type Compressor
Motor Type Characteristics
Current Relay RSIR and CSIR
•Sense starting current to main (run) windings
•Contacts normally open
•Contacts close and then release in less than 1 second
as motor starts
•Must be installed vertically since contacts open by
gravity
PTC Relay RSIR and PSC
•Sense starting current to start winding
•Solid state device whose resistance increases with
heat from current as motor starts
•Takes 3 to 10 minutes to cool down between operating
cycles
Potential Relay CSR •Sense voltage generated by start winding
•Contacts normally closed
•Contacts open in less than 1 second as motor starts
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
29
Potential Type Relay Supplier Code Designations
In recent years, Tecumseh has used an increasing
number of potential relays with hermetic compres-
sors. A large number of these have been used on air
conditioning applications, but there are also many
other applications. Since there are many variations
with regard to these relays such as number of termi-
nals, coil group, hot pick up, and mounting posi-
tion, an explanation of the code numbers should be
useful in the field.
Tecumseh has two major suppliers of potential
relays: the General Electric Company and the sup-
plier of White Rodgers relays. An explanation of the
code designation for relays manufactured by each of
these companies is provided in Figures 3-20 and 3-
21.
Figure 3-20.
Explanation of GE Potential Relay Code.
3ARR3- A 3
Potential Relay
Type Mounting
Position
C
Number of
Terminals and
Bracket
5
Coil Group
(Continuous
Voltage)
Calibration
(Hot Pickup)
(Volts)
A = 5 screw terminal "L" bracket
B = 5 screw terminal Flat bracket
C = 3 screw terminal "L" bracket
D = 3 screw terminal Flat bracket
E = 5 quick connect terminal "L" bracket
See note on page 31.
1 = Face down
2 = Face up
3 = Face out — numbers horizontal
4 = Face out — rotated 90 clockwise from number 3 position
5 = Face out — numbers upside down - horizontal
6 = Face out — rotated 90 counterclockwise from number 3 position
A = 260-280
B = 280-300
C = 300-320
D = 320-340
E = 340-360
F = 350-370
G = 360-380
H = 365-395
J = 120-130
K = 130-140
Note: Room temperature
calibration is 5 to 7% lower
than these values.
2 = 168
3 = 332
4 = 502
5 = 253
6 = 420
7 = 130
8 = 214
10 = 375
L = 140-150
M = 150-160
N = 160-170
P = 170-180
R = 180-190
S = 190-200
T = 200-220
U = 220-240
V = 240-260
W = 210-230
Example: 3ARR3-A5C3
30
Chapter 3
Figure 3-21.
Explanation of White Rodgers Potential Relay Code.
128- 12 2- 1335C A
Type of
Bracket Mounting
Position
Contact
Structure
Terminals,
Type and
Location
Customer's
Part Number
(To be stamped on relay)
Potential
Relay
Type
Coil Group
(Continuous
Voltage)
Calibration
(Hot Pick Up)
(Volts)
11 = Flat Bracket remote (Tecumseh)
12 = "L" Bracket (Tecumseh)
16 = "L" Bracket for "FB" model compressors
20 = "L" Bracket for Tecumseh Twins = 1 1/2 HP and larger
21 = "L" Bracket for capacitor box mounting
29 = Flat Bracket (Marion) was "14" (under cover)
See note on page 31.
1 = Face down
2 = Face up
3 = Face out - horizontal - numbers upside down
4 = Face out - 90 clockwise from number 3 position
5 = Face out - horizontal - numbers right side up
6 = Face out - 90 counterclockwise from number 3 position
2 = SPNC - less than 1 1/2 HP
6 = SPNC - 1 1/2 HP and Larger
11 = 3 screw terminal
12 = 4 screw terminal (seldom used)
13 = 5 screw terminal
23 = 5 quick connect terminals
1 = 130
2 = 170
3 = 256
4 = 336
5 = 395
6 = 420
7 = 495
A = 260-280
B = 280-300
C = 300-320
D = 320-340
E = 340-360
F = 350-370
G = 360-380
H = 365-395
J = 120-130
K = 130-140
L = 140-150
M = 150-160
P = 170-180
R = 180-190
S = 190-200
T = 200-220
U = 220-240
V = 240-260
W = 210-230
Note: Room temperature calibratio
n is 5 to 7% lower than these values.
Example: 128-122-1335CA
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
31
NOTE: As noted above, the 4th digit in the code
number of G.E. relays and the 7th digit for White
Rodgers relays indicates the position in which the
relay is to be mounted. It is of utmost importance
that the relay be mounted in the required posi-
tion.Mounting in any other position can change the
relay’s operating characteristics enough so that the
compressor will not start properly. This can result in
compressor motor failure.
Figure 3-22.
Potential type relay mounting positions.
52
46
1
52
46
1
52
46
1
52
46
1
Pos. 1 Pos. 2 Pos. 3
Pos. 4 Pos. 5 Pos. 6
32
Chapter 3
V. Selecting Capacitors
Never use a capacitor with a lower voltage rating
than that specified. A higher voltage rating than that
specified is acceptable.
A. Start Capacitor Bleeder Resistors
Modern high power factor, low current single phase
compressor motors which require start and run
capacitors used with potential type relays can create
electrical circuits which could cause starting relay
damage resulting in compressor failure.
The high voltage stored in the start capacitor could
discharge across the contacts of the starting relay
thus welding them and preventing the relay from
functioning. Capacitor failure and/or start winding
failure could result.
To eliminate this, Tecumseh Products Company
start capacitors are equipped with bleeder resistors
wired across the capacitor terminals. No start capac-
itor used in conjunction with a potential relay and
run capacitor should be installed without such a
bleeder resistor.
In an emergency where no bleeder resistor equipped
capacitors are available, then a two watt 15,000 ohm
resistor can be obtained and soldered across the
capacitor terminals.
B. Start Capacitor Substitution
If the specified start capacitor is not available, you
may use the next larger sized MFD capacitor at the
same or higher voltage rating. Do not add excessive
starting capacitance.
C. Run Capacitors
Since January 1979, capacitors provided by Tecum-
seh have contained non-PCB oils or have been con-
structed using non-PCB impregnated metallized
paper electrodes and polypropylene dielectric. These
capacitors are protected against case rupture, if fail-
ure occurs, by a device within the capacitor can. The
operation of this safety device could cause the termi-
nal end to bulge outward 1/2”. Suitable head space
and/or rubber caps should be provided when install-
ing such capacitors.
In some instances, for reasons of both space and eco-
nomics, it is advantageous to use two capacitors
whose MFD values add up to the total amount spec-
ified. In these cases, the capacitors should be con-
nected in parallel. Rated voltage for each should not
be less than that specified.
The tolerance on a run capacitor is ±10%, and
therefore only one rating figure is given. You should
not go below this figure on any application. You
may exceed this figure by a small amount, and the
limits are shown in this table:
Remember the voltage rating of all capacitors must
be the same or greater than the original rating. If
you do not know the voltage, use 370 volt capacitors
on 115 volt units and 440 volt capacitors on 230
volt units.
Figure 3-23.
15000 OHMS 2 WATT ± 20%
bleeder resistor wired across
capacitor terminals.
Table 3-8: Limits for Run Capacitor Ratings
Specific Rating Maximum Addition
10 to 20 MFD + 2 1/2 MFD
20 to 50 MFD + 5 MFD
Over 50 MFD + 10 MFD
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
33
Table 3-7: Facts About Capacitors
Capacitor Type Compressor
Motor Type Characteristics
Start Capacitor CSIR and CSR
•Designed to operate for only a few seconds
during start
•Taken out of start winding circuit by relay
•Excessive start capacitor MFD increases
start winding current, increases start winding
temperature, and may reduce start torque
•Capacitors in CSR motors should have
15,000 ohm, 2 watt bleed resistor across
terminals
•Capacitor rated voltage must be equal to or
more than that specified
•Capacitor MFD should not be more than that
specified
Run Capacitor RSIR, CSR, and PSC
•Permanently connected in series with start
winding
•Excessive MFD increases running current
and motor temperature
•Fused capacitors not recommended for CSR
and not required for PSC motors
•Capacitor rated voltage must be equal to or
more than that specified
•Capacitor MFD should not exceed limits
shown in Table 3-8 on page 32
34
VI. Identification of Terminal Pins
There are several different types of terminals used on
the various models of Tecumseh compressors.
Tecumseh terminal pins are now always thought of
in the order: Common, Start, Run. To identify the
terminal pins, we read the order exactly as we would
read a book: That is, we start at the top left hand
corner and read across the first “line” from left to
right. We then drop down to the second line starting
at the left and read across. Some compressor models
have terminal pin identification embossed on the
protective terminal cover. While the protective ter-
minal cover may identify the terminal pins, it is pri-
marily designed to reduce the risk of serious injury
or death from electrocution or terminal venting
with ignition. Never energize the system unless the
protective terminal cover is securely fastened.
Push-On Terminal Pins
P, R, AP & AR Models (1953 to phaseout)
T & AT Models
AZ & AE (Refrigeration Models)
Spade Type Terminal Pins
AU & AR26 Air Conditioning Models
AE Air Conditioning Models
AW, AB, AJ, AH & RK Models
Spade Type Terminal Pins
AV Models
Internal Thermostat
Terminal Pins
Many CL Models
Spade Type Terminal Pins
S & C Models (1955 to phaseout)
AK Models
Figure 3-24.
Current arrangements.
Common
RunStart
Common
RunStart
Common Start
Run
Common
Run
Start
A LOOK AT SERVICE SAFETY
Compressor Motor and Component Information
35
Screw-On Type Terminal Pins
AG, AN & SF Models
Screw-On Type Terminal Pins
CL Models
Screw-On Type Terminal Pins
AN Terminals
Figure 3-24.
Current arrangements - continued.
Common
Run
CS
RT
3
T1T2
Start
Run
1 Phase L
3
3 Phase
L
2
3 Phase
L
1
3 Phase
Common
1 Phase Start
1 Phase
24 Volt
Compressor
Sensors Line Voltage
Crankcase Heaters
Use Copper Conductors Only
Compressor
Power 2 Speed Motor
Connections
C2
C1L1L2L3R1R2R3
S1S
36
Chapter 3
VII. Fuse and Circuit Breaker
Sizing
The following information applies to Compressor
Motor - Branch Circuit, Short Circuit and Ground
Fault Protection only.
A. NEC Article 440
Hermetic compressors should be protected in accor-
dance with Article 440 of the National Electric
Code which calls for substantially larger circuit
breakers than are required for open type motors.
B. Maximum Size
The maximum size of the fuse or circuit breaker
used to protect against short circuit and/or ground
fault of a unit utilizing a hermetic compressor shall
be no more than the sum of 225% of the compressor
Related Load Amps (RLA) as marked on the system
serial label, plus the RLA values of each of the other
motors which use the same branch circuit.
C. Minimum Size
The minimum value of the fuse or circuit breaker
shall be no less than 175% of the RLA of the com-
pressor.
The interpretations and directions given above apply
only to single branch power supplies, and do NOT
pertain to any plug-in type of appliances. Also, see
“PSC Motor Starting” on page 18.

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