Inverter Compressor - GE PFSS9PKY Technical Service Manual

Inverter Compressor

Caution: Do not attempt to direct-start the
compressor. The compressor operates on a 3-phase
power supply. Applying 120 VAC to the compressor
will permanently damage the unit. It is not possible
to start the compressor without an inverter.
The compressor is a reciprocating, multi-speed,
4-pole type. It operates on 3-phase, 80 to 240 VAC
within a range of 400 to 700 Hz.
Note: Certain voltmeters will not be able to read
voltage output or frequency from the inverter.
Compressor wattages at various speeds are:
• LOW - 65 watts
• MED - 100 watts
• HIGH - 150 watts
The compressor is controlled by the inverter board,
located in the main board compartment. The
inverter board receives its signal from the main
control board. Varying the frequency to the inverter
changes the compressor speed.
Main
Board
Compressor speed is based on the temperature
set point in conjunction with the specifi c cabinet
temperature. Speeds are selected according to
the following cabinet temperatures, with freezer
temperature being the primary:
• 7°F to 19.5°F above freezer set point = high
speed.
• 4.5°F to 6.5°F above freezer set point = medium
speed.
• 1°F to 4°F above freezer set point = low speed.
• 1°F to 2.5°F above refrigerator set point = low
speed.
Inverter
COMP
Inverter
Board
120 VAC
• 3°F to 5°F above refrigerator set point - medium
speed.
• 5.5°F to 7°F above refrigerator set point - high
speed.
Note: The compressor will run at medium speed if
the freezer temperature is 20°F or more above the
setpoint.
The use of 3-phase power eliminates the need for
the relay, capacitor, and individual start and run
windings; therefore, the start, run, and common
pins found on conventional compressors are not
applicable on this 3-phase model. Compressor pin
functions are identical and compressor lead wire
confi guration is of no importance. A resistance of
9 Ω to 11 Ω should be read between any 2 of the
3 pins. Should an opening occur in the compressor
winding or should one of the compressor lead wires
become open or disconnected, the inverter will stop
voltage output to the compressor.
Compressor operation is extremely smooth and
cool. The compressor exterior may be slightly higher
than room temperature while operating; therefore, it
may be diffi cult to detect a running unit.
To verify that the compressor is running:
Disconnect power from the unit and place a hand
on the compressor. Reconnect power and feel for
a vibration when the compressor tries to start. It
may take up to 8 seconds before the compressor
attempts to start.
• When ordering a replacement compressor, order
both the compressor and inverter. Replace
the compressor fi rst. If, after compressor
installation, the compressor fails to start,
replace the inverter.
• When servicing the compressor, it is important
to dress the wiring to keep low voltage DC wiring
and 120 VAC wiring separate.
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