Delta VFD fault codes

Common causes

• Acceleration or deceleration time too short
• Short circuit or earth fault in the motor or cable
• Damaged IGBT or current sensor

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

• Deceleration too fast (regenerated energy)
• High supply voltage
• Braking resistor or brake transistor faulty

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 voltage too low or a phase missing
• Weak DC bus capacitors
• Faulty pre-charge relay or resistor

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

• Blocked heatsink or failed fan
• High panel temperature
• Faulty temperature sensor

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

Common causes

• Load higher than the drive rating for too long
• Wrong motor parameters

What to check

• Compare motor current with the drive's rated current
• Check the motor and machine for mechanical problems

Common causes

• Motor overloaded
• Wrong motor rated current setting

What to check

• Check the motor rated current parameter
• Check the load and motor cooling

Common causes

• Motor or cable insulation failure
• Damaged output stage

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

• Missing or weak supply phase
• Loose input terminals
• DC bus ripple from aged capacitors

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

• Control board memory fault
• Power interruption while saving parameters

What to check

• Reset to factory settings and set parameters again
• If it repeats, the control board needs repair

Common causes

• Fault in the protection circuit on the power or control board

What to check

• Power off, wait for the DC bus to discharge, power on again
• Repeating HPF usually means board repair