Phase UW Short

What does F42 mean?

A short circuit condition has been detected between motor phases U and W, or in the wiring connecting drive output terminals U and W to the motor. This indicates an unintended low-resistance path between these phases.

• Short circuit between phase U and phase W windings in the motor.
• Internal short circuit in the drive's output power module.
• Power cable damage causing conductors U and W to short.
• Incorrect motor connection or wiring error.

Click steps to track your progress.

1. 1

   Disconnect the motor from the drive output terminals (U, V, W).

2. 2

   Measure resistance between drive output terminals U and W with the motor disconnected; expect an open circuit (infinite resistance) if no internal drive fault.

3. 3

   Measure resistance between motor phases U and W; expect a low resistance reading (continuity across the motor winding).

4. 4

   Inspect the wiring between drive output terminals U, W and motor phases U, W for any physical damage or direct short circuits.