VW Short Fault

What does 43 mean?

This fault indicates that excessive current has been detected between the 'V' and 'W' output terminals of the controller. This is typically caused by a short circuit either within the motor windings themselves or in the external wiring connecting the controller to the motor. This is a critical fault that can cause immediate and severe damage to the controller's inverter section.

• Internal short circuit within the motor windings (V to W phase or V/W to ground).
• Insulation breakdown of the motor power cables between phases V and W, or either phase to ground, due to abrasion or chemical exposure.
• Failure of the drive's output power stage (e.g., IGBT shorting between phases V and W).
• Contactor or motor disconnect switch failure, causing a short between phases V and W at the drive output terminals.
• Water or conductive debris ingress into the motor terminal box or drive output terminals causing a phase-to-phase short.

Click steps to track your progress.

1. 1

   1. Disconnect the motor power cables from the drive output terminals U, V, W. Measure resistance between U-V, V-W, W-U, and each phase to ground using a multimeter (Ohm setting).

2. 2

   2. Inspect the motor power cables visually for any signs of physical damage, insulation cuts, or discoloration from overheating.

3. 3

   3. Using a megohmmeter, measure the insulation resistance of the motor windings to ground and between phases (e.g., V-W) with at least 500VDC.

4. 4

   4. If the motor and cables are isolated and confirmed good, perform a static check of the drive output stage (e.g., with a diode test function on a multimeter across output terminals to DC bus).

5. 5

   5. Verify that drive parameters P5-01 (Motor Rated Current) and P5-02 (Motor Rated Voltage) are correctly set according to the motor nameplate.