Armature Circuit Open (Loop Confirm)

What does F901 mean?

This fault is triggered if the motor armature circuit is not closed before the "Loop Confirm" signal asserts, preventing the drive from establishing a closed current path to the motor. It indicates a disconnection that inhibits motor operation and often occurs during the drive's startup sequence.

• Disconnection or damage in the motor armature power cabling between the drive and the motor.
• Failure of the main armature contactor to close properly, leaving the circuit open.
• Issues with the "Loop Confirm" input signaling closure prematurely when the armature path is still open.

Click steps to track your progress.

1. 1

   De-energize the drive and visually inspect all motor armature power connections for looseness or damage.

2. 2

   Perform a continuity check on the motor armature power cables and through the main armature contactor's power contacts.

3. 3

   Confirm that the "Loop Confirm" input signal accurately reflects the actual closed state of the armature circuit.

4. 4

   Verify the motor's armature winding resistance against manufacturer specifications.