Starting Device Operation - Whirlpool GSF26C5EXW Technical Education

Machine Compartment Components (continued)

Starting Device Operation

The starting device is an assembly consist-
ing of an overload (1) and a PTC relay (2).
The PTC relay is composed of a semi con-
ductive substance formed in the shape of a
disk (2). The disk is connected in series with
the run and start terminals which in turn con-
nect to the run and start windings. The resis-
tance of the disk material is relatively low at
room temperature. When voltage is applied
and current flows to the compressor wind-
ings, the current flowing to the start winding
heats the disk material. As the temperature
of the disk increases, the resistance of the
disk increases rapidly and limits current flow
to the start winding. At the same time cur-
rent flow through the disk is decreasing,
the effects of current flow through the run
capacitor increases. This change in current
and capacitance seen by the start winding
helps start the compressor and allows the
start winding to remain in the circuit once the
compressor is running.
NOTE: Do not disassemble the PTC device. The PTC device (2) was opened to show the inte-
rior construction and to assist in explaining the theory of operation
Checking the PTC: The easiest way to check the PTC device is to replace it with a known good
one. If a new PTC device is not available, a resistance check can be made.
1. Disconnect power to the refrigerator.
2. Disconnect the starting device from the
compressor.
3. Unplug the run capacitor form the
module.
4. Connect an Ohmmeter across the L and
S terminals.
5. If the PTC is at ambient temperature, 70
– 80 degrees F., the approximate
resistance should be between 3 and 10
OHMs. An infinite reading indicates the
PTC device is open.
Semi Conductor Disk
S
M
2
3
6-3
1