Applicable Systems
PLC
Symptoms
The PLC reports an overcurrent fault detected at the output. The drive trips to protect the power semiconductor devices.
Possible Causes
- Motor cable short circuit or ground fault in the B&R output wiring
- Motor winding insulation failure causing excessive current
- Accelerated too rapidly causing inrush current beyond the drive capacity
Troubleshooting Steps
- Step 1: Inspect the motor cable and motor windings for short circuits or ground faults with a megger
Insulation resistance is above the minimum threshold - Step 2: Reduce the acceleration time parameter to limit inrush current
Peak current stays within the drive rated value - Step 3: If the motor is defective, repair or replace the motor
New motor draws current within rated range
How to Reset
To reset: Resolve the overcurrent root cause, then reset the fault via the keypad or cycle power.
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Source: B&R Automation System Manual, B&R Industrial Automation
Category: PLC & VFD
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