Phase W Fault

What does 40 mean?

This fault indicates a phase-to-ground fault has been detected specifically on the 'W' phase wiring between the controller and the motor. This could be due to damaged insulation or a direct short. Such a fault poses an electrical safety hazard and can damage both the controller and motor if unresolved.

• Insulation breakdown of the motor cable for phase W, causing a short circuit to ground (e.g., conduit, motor frame).
• Moisture ingress or contamination at motor terminal W, leading to a conductive path to ground.
• Internal short circuit in the motor winding connected to phase W, specifically to the motor frame.
• Damaged output terminal block for phase W on the controller, creating a path to the controller's chassis ground.
• Loose or frayed strand of phase W wire touching exposed ground metalwork within the terminal box.

Click steps to track your progress.

1. 1

   1. Immediately disconnect the motor cable for phase W from the controller's W terminal.

2. 2

   2. Measure insulation resistance from the controller's W terminal (with motor cable disconnected) to ground using a megohmmeter (e.g., 500V DC). It should be >1 MOhm.

3. 3

   3. Measure insulation resistance of the motor cable (W phase conductor) from the controller's W terminal end to ground (e.g., cable shield or conduit ground) using a megohmmeter.

4. 4

   4. Perform an insulation resistance test on the motor winding from the W terminal to the motor frame ground using a megohmmeter.

5. 5

   5. Visually inspect the motor cable for phase W along its entire length for any cuts, abrasions, or signs of damage.