Input Contactor Contact Stuck-up

What does 34 mean?

This fault presents in two scenarios: either the KMC contactor's output from the master control PCB is off, but an input signal indicates the contactor is closed (stuck-up), or the KMC output is on, but no input signal is detected, implying a failure to close. This indicates a discrepancy between the commanded state and the actual status of the KMC contactor.

• KMC contactor auxiliary contacts are mechanically stuck in the closed position.
• Failure of the KMC contactor's main or auxiliary contacts to close when commanded by the master control PCB.
• Malfunction of the input terminal detecting circuit that monitors the KMC contactor status.
• Welded contacts within the KMC contactor due to overcurrent or age.
• Wiring error between the KMC contactor and the detecting terminal on the master control PCB.

Click steps to track your progress.

1. 1

   Physically inspect the KMC contactor for any signs of mechanical sticking or damage, and confirm its open/closed state.

2. 2

   Measure the voltage/continuity at the input detecting terminal for KMC status, both when the KMC coil is de-energized and energized.

3. 3

   Verify the output signal from the relay KMC on the master control PCB, ensuring it correctly commands the contactor.

4. 4

   Check the wiring integrity between the KMC contactor and the detecting terminal on the master control PCB for breaks or shorts.