What causes an OPF1 fault on the AT12 drives?

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Issue:

Getting OPF1 fault on the AT12 drive.

Product Line:

ATV12

Environment:

OPF1 faults

Cause:

1 phase loss between the drive and motor.

Resolution:

This fault is triggered when the drive detects one of the motor phases has been lost (or has very low current) for more than 500 msec.

Troubleshooting steps:

Check all connections between the drive and motor. Re-seat connections and check for torque.

Using clamp-ons, measure current on each motor lead to see if you have low current on one or more phases.

Using a 1000 V Megger, megger out the motor and the leads.

For testing, go to the FLT menu: set Output Phase Loss to No, disconnect the motor leads from the drive, run the drive at 20Hz, 40Hz, and 60Hz, and measure output voltage phase to phase at each speed. You want the voltages balanced and correct for the speed you're running the drive. Be aware that your meter may read higher output voltage than you might expect (for example, you may measure over 500V at 60Hz) if your meter doesn't have a PWM filter. This is because you're measuring a PWM (Pulse Width Modulated) waveform and not true AC. Be sure to turn OPL detection back on, after testing.

Power cycle the drive and then try to run again.