R-Pro › Field cases › Air conditioning
Inverter Malfunction from Unstable Supply Voltage
Likely causes
Voltage drop during startup from undersized wiring
Check: Measure voltage both during run and at startup (large gap = wiring issue)
What to do: Measure voltage both during run and at startup (large gap = wiring issue) → Tighten compressor terminal screws and check contacts → Verify wire gauge and length (account for inrush current) → Disconnect other equipment from the circuit and retest → If voltage instability persists, contact utility or licensed electrician
Voltage variation from poor terminal contact
Check: Tighten compressor terminal screws and check contacts
What to do: Tighten compressor terminal screws and check contacts → Verify wire gauge and length (account for inrush current) → Disconnect other equipment from the circuit and retest → If voltage instability persists, contact utility or licensed electrician
Interference from other equipment on the same circuit
Check: Verify wire gauge and length (account for inrush current)
What to do: Verify wire gauge and length (account for inrush current) → Disconnect other equipment from the circuit and retest → If voltage instability persists, contact utility or licensed electrician
Unstable supply voltage causes inverter malfunction or protective shutdown. Check power quality. For 3-phase inverters, phase loss causes immediate protective shutdown. Always measure all three phase voltages.
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