Inverter - GE ZIS360NR Technical Service Manual

Inverter

Warning: Disconnecting the 6-pin connector does not disconnect power (120 VAC) from the
inverter. The refrigerator must be unplugged before servicing the inverter.
Note: Certain voltmeters will not be able to read voltage output from the inverter. If no voltage or erratic
voltage is measured, it does not necessarily indicate a faulty inverter.
The inverter receives 120 VAC line-in from the power supply. The inverter converts this single-phase,
60 Hz, 120 VAC into 3-phase, 230 VAC, with frequency variations between 57 Hz and 104 Hz. This
voltage is delivered to the compressor through 3 lead wires. Each wire will carry identical voltage and
frequency. When checking inverter voltage output, connect the test-meter leads to any 2 of the 3
compressor lead wires. The same reading should be measured between any 2 of the 3 wires.
Note: The compressor leads must be connected to measure voltage output. If the compressor wires
are not connected, or if an open occurs in one of the 3 lead wires or in the compressor, the inverter will
stop voltage output.
The inverter controls compressor speed by frequency variation and by pulse width modulation (PWM).
Changing frequency and PWM will cause an effective voltage between 80 and 230 VAC to be received at
the compressor.
• Low speed (1710 rpm) - 57 Hz
• Medium speed (2100 rpm) - 70 Hz
• High Speed (3120 rpm) - 104 Hz
The inverter receives commands from the main control board.
The main control board will send a (PWM) run signal between 1.5
and 3.5 VDC effective voltage to the inverter. The signal voltage at
the inverter should be equal to the signal voltage sent by the main
control board. The inverter will select compressor speed (voltage
output) based on this signal. A signal voltage from the main
control board (J15 connector ) lower than 5 VDC indicates a
faulty main control board. The main control board will only send a
run signal to the inverter when the compressor should be on.
Note: When measuring signal voltage (from the main control
board) at the inverter, disconnect the wire harness connector at
the inverter and measure the voltage at the connector.
The inverter will monitor compressor operation and if the
compressor fails to start or excessive current draw (4 amps
maximum) is detected, the inverter will briefly stop voltage output.
The inverter will then make 12 consecutive compressor start
attempts (once every 12 seconds). If after 12 attempts the
compressor has not started, an 8-minute count will initiate. After
the 8-minute count, the inverter will attempt to start the
compressor again. If the compressor starts, normal operation will
resume. If the compressor fails to start, this process will be repeated. Removing power to the unit will
reset the inverter count. When power is restored, the inverter will attempt to start the compressor within
8 seconds.
The inverter has a built-in circuit protection to guard against damage from a failed or shorted
compressor. However, if a failed compressor is diagnosed, order a new compressor and inverter. If the
compressor fails to start after replacement, replace the inverter.
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J15