What causes fault code VFD-IGBT1 (VFD IGBT / Power Module Fault)?

IGBT module failed — semiconductor end of life or thermal stress damage. Output short circuit — phase-to-phase or phase-to-ground at motor terminals or in cable. Gate driver board failure — IGBT gate signal not reaching power module correctly. Snubber capacitor failed — voltage spike damaged IGBT. Lightning or power surge damaged power stage components

How do I fix fault code VFD-IGBT1?

CAUTION: Disconnect all power and wait 5 minutes for DC bus to discharge before opening drive. Disconnect motor cables from VFD output T1/T2/T3. With multimeter on diode check, test each IGBT: positive lead to DC+, negative to T1, T2, T3 (should show ~0.4-0.7V). Reverse leads (should show OL). Then positive to T1/T2/T3, negative to DC- (should show ~0.4-0.7V). Any reading of 0 ohm or short indicates a failed IGBT. This is typically a factory or authorized service center repair. Check root cause (output short, power surge) before installing replacement drive

VFD IGBT / Power Module Fault

VFD-IGBT1

VFD internal power semiconductor (IGBT) module fault detected. Drive detected a short circuit or desaturation condition in the output power stage.

critical vfd

vfd igbt power module semiconductor short circuit

Probable Causes (ranked)

IGBT module failed — semiconductor end of life or thermal stress damage
Output short circuit — phase-to-phase or phase-to-ground at motor terminals or in cable
Gate driver board failure — IGBT gate signal not reaching power module correctly
Snubber capacitor failed — voltage spike damaged IGBT
Lightning or power surge damaged power stage components

Fix Steps

1 CAUTION: Disconnect all power and wait 5 minutes for DC bus to discharge before opening drive
2 Disconnect motor cables from VFD output T1/T2/T3
3 With multimeter on diode check, test each IGBT: positive lead to DC+, negative to T1, T2, T3 (should show ~0.4-0.7V). Reverse leads (should show OL). Then positive to T1/T2/T3, negative to DC- (should show ~0.4-0.7V)
4 Any reading of 0 ohm or short indicates a failed IGBT
5 This is typically a factory or authorized service center repair
6 Check root cause (output short, power surge) before installing replacement drive

Field Trick

You can check IGBTs in the field with a standard multimeter on diode check. Each IGBT should read like two diodes in series. If any read zero in both directions, that module is shorted. This 2-minute test tells you if the drive is repairable or scrap.

Suggested Replacement Parts

Parts matched to fault category: Vfd

Allen-Bradley PowerFlex 525 AC Drive 1HP P/N: 25B-D2P3N114 1HP, 480V, 3-phase, built-in EtherNet/IP, EMC filter

AutomationDirect $395.00 Amazon $450.00 Grainger $520.00

ABB ACS580 General Purpose Drive 2HP P/N: ACS580-01-05A7-4 2HP, 480V, built-in safe torque off, adaptive programming

AutomationDirect $425.00 Amazon $480.00 Grainger $550.00

GS20 AC Drive 1HP (Budget Option) P/N: GS20-20P5 1HP, 230V, sensorless vector, compact size — good replacement for testing

AutomationDirect $149.00 Amazon $175.00

Prices are estimates. Verify part numbers match your equipment before ordering.

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