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FAN MOTOR
The fan motor is a permanent split capacitor (PSC) type
motor. This motor is common in air-conditioning sys-
tem applications. A PSC motor does not require the use
of a relay and always has a run capacitor connected
between the run and start windings of the motor. See
Figure 62.
The 52S series fan motor has a motor shaft extended
through both ends. It powers both the indoor and the out-
door fans. It has permanently sealed bearings that re-
quire no lubrication. There are many different fan motor
models, but they typically are 2 speed or 3 speed and
in 2 voltage categories, 208/230 and 265 volts.
FAN MOTOR TROUBLESHOOTING
Refer to Figure 63 for a basic fan motor troubleshooting
chart.
Ⅲ TOOLS NEEDED — The following list includes rec-
ommended tools and devices for working on the fan
motor of 52S units.
Gloves
Safety Glasses
Regular and Phillips Head Screw Drivers
Small Adjustable Wrench
Allen Wrench Set (extra length)
3
⁄
8
-in. Socket Set
Channel Lock Pliers
Volt-ohmmeter
5
⁄
16
-in. and
1
⁄
4
-in. Nut Drivers
Before cleaning, servicing, performing maintenance
or removing the chassis from the wall sleeve, discon-
nect all power to the unit to avoid the possibility of
electrical shock and personal injury. Only trained
and qualified service personnel should perform
installation and service procedures on these units.
Untrained personnel may perform basic maintenance
tasks such as cleaning and replacing filters. Refer to
GENERAL DISASSEMBLY section of this manual
for proper procedures to disconnect power to 52S
units.
The Manufacturer reserves the right to discontinue, or
change at any time, specifications or designs without
notice and without incurring obligations.
Consider the following safety issues:
• Prior to performing any service or maintenance on
electrical equipment you must Disconnect All
Power.
• New and unfamiliar tasks should be performed under
the supervision of an experienced service technician.
• Personal protective equipment, such as safety glasses
and work gloves, should be worn.
• The floor around the work area should be clean and
free of debris.
• Make sure tools are the correct tools for the job, and
that they are working properly and in good condition.
• The 52S unit may weigh up to 150 pounds. Use a lift-
ing device or ask for assistance if the unit must be
moved.
BASIC FAN MOTOR ELECTRICAL TESTS
There are 2 basic electrical tests for PSC fan motors
that will determine the electrical state of the motor. The
first test requires checking the electrical resistance be-
tween the motor windings. The second test requires
checking the electrical resistance between the motor
windings and ground. These tests may be accomplished
by performing the following steps:
1. DISCONNECT ALL POWER TO UNIT.
2. Remove the unit from the sleeve and open the con-
trol box as detailed in the GENERAL DISASSEM-
BLY section.
3. Label and disconnect the fan motor wires from the
push button switch and capacitor as shown in
Figure 5. Two-speed motors have 2 wires on the ca-
pacitor and 2 wires on the push button switch.
Three-speed motors have 2 wires on the capacitor
and 3 wires on the push button switch. Refer to the
unit wiring diagram inside the control box.
4. Measure and record the resistance between the black
wire and each of the other wires. Make sure the mo-
tor is cool before attempting to measure resistance.
The internal thermostat of the motor may be electri-
cally open and will not close until the motor cools.
See Figure 64 for typical motor winding resistance
measurements. The resistance values in the table
are approximate. Values that are within 10% of those
listed are acceptable. If the motor in your model is
not listed, find a motor of similar horsepower and
voltage on the chart and compare it to the resistance
measurements of your motor.
5. Measure the resistance of each of the motor wires to
the motor casing. The resistance should be infinite.
Make sure the motor is cool before attempting to mea-
sure resistance. The internal thermostat of the mo-
tor may be electrically open and will not close until
the motor cools. A motor that has measurable re-
sistance to ground is shorted to ground and must be
replaced.
FIGURE 62 — TWO-SPEED, PERMANENT
SPLIT CAPACITOR MOTOR (PSC)
52S
SERIES
32