GPG14M Service Manual

SERVICING
39
RELAY, START
A potential or voltage type relay is used to take the start
capacitor out of the circuit once the motor comes up to speed.
This type of relay is position sensitive. The normally closed
contacts are wired in series with the start capacitor and the
relay holding coil is wired parallel with the start winding. As
the motor starts and comes up to speed, the increase in
voltage across the start winding will energize the start relay
holding coil and open the contacts to the start capacitor.
Two quick ways to test a capacitor are a resistance and a
capacitance check.
S-15A RESISTANCE CHECK
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Discharge capacitor and remove wire leads.
WARNING
Discharge capacitor through a 20 to 30 OHM
resistor before handling.
OHMMETER
CAPACITOR
TESTING CAPACITOR RESISTANCE
2. Set an ohmmeter on its highest ohm scale and connect
the leads to the capacitor -
a. Good Condition - indicator swings to zero and
slowly returns to infinity. (Start capacitor with
bleed resistor will not return to infinity. It will still
read the resistance of the resistor).
b. Shorted - indicator swings to zero and stops there
-replace.
c. Open - no reading - replace. (Start capacitor would
read resistor resistance.)
S-15B CAPACITANCE CHECK
Using a hookup as shown below, take the amperage and
voltage readings and use them in the formula:
VOLTMETER
CAPACITOR
AMMETER
15 AMP
FUSE
TESTING CAPACITANCE
WARNING
Discharge capacitor through a 20 to 30 OHM
resistor before handling.
Capacitance (MFD) = 2650 X Amperage
Voltage
S-16A CHECKING FAN AND BLOWER MOTOR
WINDINGS (PSC MOTORS)
The auto reset fan motor overload is designed to protect the
motor against high temperature and high amperage condi-
tions by breaking the common circuit within the motor,
similar to the compressor internal overload. However, heat
generated within the motor is faster to dissipate than the
compressor, allow at least 45 minutes for the overload to
reset, then retest.