What are the probable causes of HDF fault on Altivar 71 drive.

HDF(IGBT Desaturation) fault appears only on the drive >90KW when a short-circuit is present on the IGBT module by measurement of the transistor desaturation.

Probable causes:

• Short circuit or grounding on the output phases.
• Transistor IGBT in short circuit

Remedies:

• Check the insulation motor and the wiring.
• There is a cabling mistake in the drive (bad connection of connector on the boards)
• Bad tightening of nuts on the gate drive boards
• Disturbances on the control cable (logic input, power removal PWR, +24V...)
• Made transistor diagnostic.
• Change power board, gate drive board or transistors.

Note: The insulation test on the motor and motor cables must be made at 1000V.

Released for: Schneider Electric India