18
Inverter (cont.)
The inverter controls the 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.
The frequency can be measured at the J15 connector plug with a proper
digital multimeter.
• 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 from the J15 connector of between
4-6 VDC effective voltage to the inverter (all wires must be connected). The 4-
6 VDC indicate compressor running speed. The inverter will select the
compressor speed (voltage output) based on this signal.
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, a reading of 4-6 VDC will be measured with all wires connected. If
the inverter wiring is disconnected, the board output will measure between
10-12 VDC.
mabe CONFIDENTIAL AND PROPRIETARY INFORMATION-NOT FOR PUBLIC DISCLOSURE. January 2008