52
SERVICING
Models Equipped With A Hard Start Device
A start capacitor is wired in parallel with the run capacitor
to increase the starting torque. The start capacitor is of
the electrolytic type, rather than metallized polypropylene
as used in the run capacitor.
A switching device must be wired in series with the
capacitor to remove it from the electrical circuit after the
compressor starts to run. Not removing the start capacitor
will overheat the capacitor and burn out the compressor
windings.
These capacitors have a 15,000 ohm, 2 watt resistor
wired across its terminals. The object of the resistor
is to discharge the capacitor under certain operating
conditions, rather than having it discharge across the
closing of the contacts within the switching device such as
the Start Relay, and to reduce the chance of shock to the
servicer. See the Servicing Section for specific information
concerning capacitors.
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
Summary of Contents for DRG0361DL00001S
Page 20: ...20 SYSTEM OPERATION...
