Danfoss fault record

Alarm 16: Short Circuit

The VLT reports alarm 16 or trips instantly when the inverter output is enabled.

Meaning of the indication

The fault route is output short-circuit evidence: cable, motor, output terminals, output accessories, IGBT module and driver/current-sense circuitry.

Checking order

  1. Classify trip timing: instant enable, acceleration or load step.
  2. Disconnect motor cable only under approved lockout and verify whether the alarm condition changes.
  3. Inspect output terminals for loose strands or contamination.
  4. Check for unauthorized output capacitors or surge devices.
  5. After any module replacement, verify gate-driver health before full-power testing.

Suspect areas

Output cableMotor windingOutput accessoriesIGBT moduleGate driverCurrent feedback
Fault-specific caution

A repeated alarm 16 after module replacement can indicate an unrepaired gate-driver or current-feedback fault.

Diagnostic workflow