What causes fault code VFD-OC2 (VFD Overcurrent — Deceleration)?

Deceleration time too short — high-inertia load pumps energy back into DC bus faster than it can absorb. No dynamic braking resistor installed on a high-inertia application. Braking resistor open or wiring disconnected — check terminals DB+ and DB-. VFD DC bus capacitors degraded — cannot absorb regenerative energy. Load is overhauling — gravity or process force driving motor faster than commanded speed

How do I fix fault code VFD-OC2?

Increase deceleration time by 50-100% and retest. If application requires fast stopping, verify dynamic braking resistor is installed and connected to DB+/DB- terminals. Measure braking resistor with ohmmeter — compare to rated value on resistor nameplate. Check DC bus voltage during decel using VFD keypad monitor — should not exceed rated bus voltage (typically 800VDC for 480V drive). Enable coast-to-stop if application allows — eliminates regen entirely. For overhauling loads (downhill conveyors, hoists), install or size up the braking resistor

VFD Overcurrent — Deceleration

VFD-OC2

Drive tripped on overcurrent during deceleration ramp. Regenerative energy from the load exceeded the DC bus capacity.

high vfd conveyor packaging palletizer

vfd overcurrent deceleration braking regenerative

Probable Causes (ranked)

Deceleration time too short — high-inertia load pumps energy back into DC bus faster than it can absorb
No dynamic braking resistor installed on a high-inertia application
Braking resistor open or wiring disconnected — check terminals DB+ and DB-
VFD DC bus capacitors degraded — cannot absorb regenerative energy
Load is overhauling — gravity or process force driving motor faster than commanded speed

Fix Steps

1 Increase deceleration time by 50-100% and retest
2 If application requires fast stopping, verify dynamic braking resistor is installed and connected to DB+/DB- terminals
3 Measure braking resistor with ohmmeter — compare to rated value on resistor nameplate
4 Check DC bus voltage during decel using VFD keypad monitor — should not exceed rated bus voltage (typically 800VDC for 480V drive)
5 Enable coast-to-stop if application allows — eliminates regen entirely
6 For overhauling loads (downhill conveyors, hoists), install or size up the braking resistor

Field Trick

If you don't have a braking resistor and need a temporary fix, set decel time to 999 seconds and enable coast-to-stop. The motor will coast down naturally. Not a permanent fix but gets production running.

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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