Danfoss · VLT AutomationDrive FC 301/302
A short-circuit condition is detected either in the motor windings or within the motor wiring connecting to the frequency converter. This poses a significant risk of damage to the drive and motor if not resolved.
Click steps to track your progress.
Power down the drive and disconnect the motor leads (U, V, W) from the drive's output terminals.
Use a multimeter to measure the resistance between each pair of motor phases (U-V, V-W, W-U) for both the motor cable and motor windings. Look for resistance values close to zero Ohms.
Inspect the entire length of the motor cable for severe physical damage, crushing, or cuts that could cause phase-to-phase contact.
Open the motor terminal box and inspect for moisture, carbon tracking, or debris bridging terminals.
If the motor and cable show no short-circuit, the fault likely lies within the drive's power section (e.g., IGBT module), requiring service.