Inverter output / protection

Danfoss VLT Output Earth-Fault and Short-Circuit Path

Routes alarm 14 and alarm 16 through output insulation, terminal contamination, motor cable damage, IGBT module, gate driver and current-feedback path.

Functional path

IGBT output bridge

Current detection

Output terminals

Motor cable

Motor insulation

Protective earth

Diagnostic signals and checkpoints

Alarm 14Alarm 16Motor disconnected resultInsulation resistancePrevious power-stage repair

Technician notes

Earth fault and short circuit routes overlap but are not identical.
Do not megger through the drive output terminals.