Danfoss VFD fault codes

Common causes

• Shock load or fast acceleration
• Motor or cable fault
• Damaged power card

What to check

• Disconnect the motor cable and run the drive without load: if the fault stays, the drive itself is faulty
• Megger the motor and cable for insulation or phase-to-phase faults
• Increase acceleration/deceleration time; check for mechanical jams

Common causes

• Short circuit in the motor or cable
• Failed output stage

What to check

• Disconnect the motor; if the alarm remains, the power card needs repair

Common causes

• Motor or cable insulation failure

What to check

• Megger the motor and cable to earth
• Check for water or dust in the motor terminal box
• If insulation is fine, the output IGBT or current sensor may be faulty

Common causes

• Deceleration too fast
• Supply overvoltage

What to check

• Increase the deceleration time or enable the stall/overvoltage prevention function
• Check the braking resistor and braking transistor (if fitted)
• Measure the supply voltage – it should be within the drive's rating

Common causes

• Supply loss or low voltage
• Faulty soft-charge circuit

What to check

• Measure all three input phases under load
• Check input fuses, contactor and loose terminals
• If the supply is fine, check the DC bus capacitors and pre-charge circuit

Common causes

• Missing phase or large imbalance

What to check

• Measure all three input phases under load
• Check input fuses, contactor and loose terminals
• If the supply is fine, check the DC bus capacitors and pre-charge circuit

Common causes

• Load above the drive rating

What to check

• Reduce load or use a larger drive

Common causes

• Fan failure
• Blocked heatsink
• High ambient temperature

What to check

• Clean the heatsink and check that the cooling fan runs
• Check the panel temperature and ventilation
• Reduce the load or carrier frequency