Posts

All the articles I've posted.

• Danfoss FC302 Alarm 31 - Causes & Fix

  3 Jun, 2026

  Alarm 31 means motor phase V missing. Most often a loose wire or bad connection on phase V between drive and motor. Check wiring.

• Danfoss FC302 ALARM 30 - Causes & Fix

  3 Jun, 2026

  ALARM 30 on Danfoss FC302 means motor phase U is missing. Most likely fix: check and tighten U-phase motor cable connections.

• Danfoss FC302 Alarm 26 - Causes & Fix

  3 Jun, 2026

  Alarm 26 on Danfoss FC302 VFD means inverter/power stage fault. Most common fix: check motor cable for shorts, then replace IGBT.

• Danfoss FC302 ALARM 25 - Causes & Fix

  3 Jun, 2026

  ALARM 25 on a Danfoss FC302 VFD means brake resistor short circuit. The drive disables braking. Replace the brake resistor first.

• Danfoss FC302 VFD Alarm 16 - Causes & Fix

  3 Jun, 2026

  Alarm 16 on a Danfoss FC302 VFD means a line-to-line short circuit in the motor or motor wiring. Isolate and test cable and windings.

• Danfoss FC302 Alarm 14 - Causes & Fix

  3 Jun, 2026

  Alarm 14 on a Danfoss FC302 VFD means earth fault: current is leaking to ground. Usually a bad motor cable or motor winding insulation.

• Siemens Micromaster F0070 - Causes & Fix

  3 Jun, 2026

  F0070 means the drive did not receive a valid setpoint from the communications board. Check the comms master, wiring, and parameters.

• Siemens Micromaster F0041 - Causes & Fix

  3 Jun, 2026

  F0041 means stator resistance measurement failed during motor identification. Most often caused by loose motor wiring or wrong data.

• Siemens Micromaster F0035 - Causes & Fix

  3 Jun, 2026

  F0035 means the drive exceeded its auto-restart limit (P1211). Reset the fault and find the underlying trip cause to fix it.

• Danfoss FC302 VFD Alarm 23 - Causes & Fix

  2 Jun, 2026

  Alarm 23 means the internal cooling fan is not running or has failed. Check the fan, wiring, soft-charge fuses, and control card.

• Danfoss FC302 Alarm 22 - Hoist Brake Fault Fix

  2 Jun, 2026

  Alarm 22 on Danfoss FC302 means hoist mechanical brake did not release or feedback timeout. Check brake operation and timing parameters.

• Danfoss FC302 ALARM 20 - Causes & Fix

  2 Jun, 2026

  ALARM 20 means temperature input error: the sensor is not connected or wired correctly. Check wiring and sensor connection first.

• Danfoss FC302 VFD ALARM 18 - Causes & Fix

  2 Jun, 2026

  ALARM 18 on Danfoss FC302 means motor phase missing. Most common fix: check and tighten all motor output terminals at drive and motor.

• Danfoss FC302 Alarm 17 - Causes & Fix

  2 Jun, 2026

  Alarm 17 on Danfoss FC302 VFD means control word timeout (lost communication from PLC or fieldbus). Check master controller first.

• Danfoss FC302 VFD ALARM 15 - Causes & Fix

  2 Jun, 2026

  ALARM 15 on a Danfoss FC302 means hardware mismatch. Most often a wrong or poorly seated option card. Record parameters 15-40 and 15-41.

• Siemens Micromaster F0101 - Causes & Fix

  2 Jun, 2026

  F0101 on a Siemens Micromaster VFD means stack overflow, a processor fault. Most likely fix: run self-test routines or replace the drive.

• Siemens Micromaster F0085 - Causes & Fix

  2 Jun, 2026

  F0085 means External Fault: an input terminal stopped the drive. Check which digital input is wired for fault and fix the tripped device.

• Siemens Micromaster F0080 - Causes & Fix

  2 Jun, 2026

  F0080 means ADC lost input signal: the drive has no valid analog setpoint. Check the analog input wiring and source first.

• Siemens Micromaster F0072 - Causes & Fix

  2 Jun, 2026

  F0072 means the Siemens Micromaster lost USS setpoint data from the serial master. Check the master controller, RS-485 wiring, and settings.

• Siemens Micromaster F0071 - Causes & Fix

  2 Jun, 2026

  F0071 means USS setpoint fault: the drive lost communication with its USS master. Check the master device and wiring first.

• Siemens Micromaster F0060 - Causes & Fix

  2 Jun, 2026

  F0060 means ASIC timeout, an internal drive electronics failure. Most likely fix: reset the drive. If it returns, replace the inverter.

• Siemens Micromaster F0054 - Causes & Fix

  2 Jun, 2026

  F0054 on a Siemens Micromaster VFD means Wrong IO Board: the drive can't identify the I/O board. Usually fix by reseating or replacing the board.

• Siemens Micromaster F0052 - Causes & Fix

  2 Jun, 2026

  F0052 on Siemens Micromaster VFDs means a power stack fault. The drive cannot read power-stack data. Usually requires service or replacement.

• Siemens Micromaster F0051 - Causes & Fix

  2 Jun, 2026

  F0051 means parameter EEPROM fault on Siemens Micromaster 420/440 drives. Factory reset and re-enter parameters is the first fix.