Ingersoll-Rand 900829, Maintenance Manual

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Electrical Maintenance
41
Evaporator Fan Motors
NOTE: Non-repairable fan motor assemblies are
used. If a motor malfunctions, it must be
replaced.
The evaporator fan motors are maintenance free.
If erratic or intermittent operation is observed, the
current draw of the motor should be measured
while proper voltage is applied. The current draw
for a evaporator motor is approximately 6.1 to 6.2
amps at 13 volts.
If any of the evaporator fan motors do not run at
all, check fuses F3, F4, F9, and F10 and the output
to the evaporator fans when they should be
energized.
Evaporator Fan Motor Removal and
Installation
Removal
1. Turn the unit off.
2. Remove the evaporator cover.
3. Disconnect the motor power plug.
4. Remove the fan motor mounting bolts (4).
5. Remove the fan motor from the evaporator.
Installation
1. Attach the fan motor to the evaporator and
tighten the fan motor mounting bolts (4).
2. Connect the fan motor power plug.
3. Install the evaporator cover.
4. Start the unit and verify correct fan motor
operation.
Electric Standby Circuits
If the unit does not run in the electric standby
mode use the following procedure.
Make sure the unit is connected to the proper
power source.
Check the power cable receptacle for power. If
power is there, check for power at the unit
terminal plug.
If the contactor is pulled down and the overload
relay is closed, but the standby motor fails to start,
the trouble is probably in the standby motor.
If the contactor is not pulling down proceed as
follows:
1. Check the AC line voltage and the transformer
input fuse. If the AC line voltage is acceptable
and the transformer input fuse is intact, go to
step 2.
2. Measure the transformer output voltage (AC)
at Connector 1 on PCB1 in the ECM. Measure
the voltage between wires X1 (pin B8) and X4
(pin C8). The voltage reading should be
approximately 12/24Vac (depending on the
unit voltage). If not, check the transformer
output fuses located in the main wire harness
near the 2-pin connector that connects wires
X1 and X4 in the main wire harness to wires
X1 and X4 from the transformer. If the fuses
are good and the X1 and X4 circuits have
good continuity, the transformer is defective.
If the transformer output voltage is acceptable,
go to step 3.
3. Check the rectifier output voltage (DC) on the
2R wire at the power supply capacitor. If this
voltage is less than approximately 12/24Vdc,
and if the 2R circuits to the rectifiers and the
0V and 11.5V circuits from the rectifiers to the
transformer have good continuity, the rectifier
bridge is defective. If the rectifier output
voltage is acceptable, go to step 4.
4. Check the voltage on 2R wire at the standby
power relay. If voltage is not present, check
the continuity of the 2R wire from the power
supply capacitor. If the voltage on the 2R wire
at the standby power relay is acceptable, go to
step 5.
5. Check the voltage on both ends of the 2RB
wire at the standby power relay. If voltage is
not present, the 2RB wire is open. If the
voltage on both ends of the 2RB wire is
acceptable, go to step 6.
CAUTION: Take precautions to ensure
the unit will not accidently start while
servicing the system.