Use this tool to look up variable speed drive fault codes and get immediate guidance on causes and corrective actions. Select your drive manufacturer, then search by fault code or symptom. Coverage includes ABB, Siemens, Danfoss, Schneider Altivar, Mitsubishi FR-series, Yaskawa, Allen-Bradley PowerFlex, WEG CFW-series, and Invertek Optidrive.
Always isolate the drive before inspecting internal components. If a fault code is not listed or fault recurs after reset, contact a qualified drive engineer before further restart attempts.
86 faults found
Motor short circuit, earth fault, motor overload, output cable fault, drive output phase loss.
Check motor and output cable insulation resistance. Verify motor is not mechanically seized. Check output terminals for earth fault. Reset and test at low speed.
If fault repeats within minutes or insulation resistance is below 1 MΩ, isolate and call an engineer.
Deceleration ramp too fast for load inertia, supply voltage too high, regenerative load braking without braking chopper.
Increase deceleration ramp time. Verify supply voltage is within drive rating. Check braking resistor connection if fitted.
If supply voltage is within spec and fault persists, internal capacitor or IGBT fault suspected — do not reset repeatedly.
Earth fault on output cable or motor winding. High leakage current through cable screen.
Measure insulation resistance motor-to-earth with drive disconnected. Check cable screen termination at both ends. Check motor terminal box for moisture.
Insulation below 1 MΩ — motor requires rewinding or replacement before restart.
Supply voltage too low, supply phase loss, internal DC bus fault, incoming fuse blown.
Check incoming supply voltage on all three phases. Check incoming fuses or MCB. Verify supply is stable under load.
If supply is correct and fault persists, internal power supply or rectifier fault — requires engineer.
Motor overloaded, ambient temperature too high, motor cooling blocked, motor fan failed.
Reduce load. Check motor cooling fins and fan. Measure motor current vs nameplate rating. Check ambient temperature in motor enclosure.
If motor is hot to touch and overloaded, allow to cool fully before restart. Repeated overtemperature shortens winding life significantly.
Panel ambient too hot, drive cooling fan blocked or failed, drive vents blocked with dust.
Check drive cooling fan is running. Clean drive vents. Measure panel ambient temperature — should be below drive rating (typically 40–50°C).
If cooling fan has failed, replace before restarting. Fan part numbers available from ABB distributor.
Incoming supply phase missing, loose terminal on input contactor or fuse, blown input fuse.
Measure voltage on all three input phases at drive terminals L1, L2, L3. Check incoming fuses and contactor terminals.
Do not run single-phase — drive will sustain internal damage. Isolate until supply is restored.
Open circuit on one output phase: broken cable, loose terminal, tripped output contactor, motor winding open.
Check output cable connections at drive terminals U, V, W and at motor terminal box. Measure motor winding resistance across each phase pair.
Winding imbalance >5% — motor fault, requires replacement or rewind.
Motor data incorrectly entered, motor cable too long, motor not connected.
Re-check all motor nameplate parameters entered into drive: kW, voltage, current, frequency, speed. Ensure motor is connected and not mechanically loaded during ID run.
Repeat after correcting parameters. If fault persists with correct data, check for output wiring fault.
Braking resistor overloaded — duty cycle too high, resistor undersized for application.
Increase deceleration ramp time to reduce braking load. Verify resistor size matches drive specification.
If brake resistor is physically damaged or discoloured, replace before resuming operation.
Output short circuit, earth fault, motor cable fault, motor winding fault.
Disconnect motor cable at drive output terminals. Measure insulation motor-to-earth and phase-to-phase. Check cable route for physical damage.
If drive IGBT is suspected (no external fault found), requires specialist workshop testing.
Regen load, deceleration too fast, supply voltage high.
Extend deceleration ramp time. Check supply voltage. Verify braking chopper/resistor if fitted.
Repeated DC bus faults without clear cause — internal capacitor degradation possible, contact engineer.
Low supply voltage, phase loss, internal pre-charge fault.
Check all three supply phases and incoming fuses.
Phase loss confirmed — do not restart until supply rectified.
Cooling fan fault, blocked vents, high ambient.
Check internal cooling fan. Clean vents. Reduce ambient if possible.
Fan replacement required if failed — operate with fan failed risks permanent IGBT damage.
Motor temperature sensor tripped. Motor overloaded or cooling restricted.
Allow motor to cool. Verify PTC/KTY sensor wiring to drive terminals. Check motor load.
If sensor circuit is open/short, verify sensor continuity before assuming motor fault.
Persistent overload — motor running above rated current for extended period.
Check driven load for mechanical obstruction or overload. Verify motor current against nameplate rating.
If motor has been in sustained overload, inspect motor and bearings before restart.
Parameter memory corruption, drive firmware issue.
Restore factory parameters and re-commission. Back up parameters before reset if possible.
Repeated EEPROM faults may indicate control board failure — contact Siemens service.
Internal power supply fault, gate driver fault.
Cycle power (wait 5 minutes after isolating). Check for external causes (voltage spikes, earthing).
If fault persists after clean power cycle, internal hardware fault — do not continue operating.
Internal 10V supply fault or short circuit on external circuit connected to drive 10V terminal.
Disconnect any external equipment from the drive 10V terminal. Check for wiring faults on analogue inputs.
If fault clears with external wiring disconnected, trace and repair short circuit in control wiring.
Analogue input reference signal lost — e.g. 4–20 mA signal dropped to below 2 mA.
Check reference signal cable from PLC, sensor, or potentiometer. Verify signal source is powered and outputting correct range.
If signal source is healthy and fault persists, analogue input card fault possible.
One or more input phases missing at drive terminals.
Check all three incoming phases. Check upstream fuses and contactors.
Do not run on phase loss — proceed only after supply confirmed healthy on all three phases.
Regen braking, fast deceleration, high supply voltage.
Extend deceleration ramp time. Confirm supply voltage within spec.
If braking resistor fitted, check connection and continuity of resistor.
Low supply voltage, phase loss, internal DC bus fault.
Check incoming supply. Verify all fuses.
Persistent DC undervoltage on healthy supply — internal fault, contact engineer.
As TRIP 5 — DC bus voltage exceeded during operation.
As TRIP 5.
As TRIP 5.
As TRIP 6.
As TRIP 6.
As TRIP 6.
Drive has been overloaded beyond rated current continuously.
Check motor load for mechanical issues. Verify drive is correctly sized for motor.
If drive is undersized, replacement with correctly rated unit required.
Motor PTC thermistor tripped — motor overtemperature.
Allow motor to cool. Check motor load and ambient temperature.
Confirm thermistor circuit is intact before restart.
Output short circuit, earth fault, rapid acceleration, load spike.
Disconnect output and check insulation resistance. Increase acceleration ramp time.
Repeated overcurrent trips with no external fault — IGBT fault possible.
Earth fault detected on output. Motor or cable insulation breakdown.
Measure insulation motor and cable to earth with drive isolated.
Insulation below 1 MΩ — motor or cable must be repaired before restart.
Drive cooling fan blocked or failed, ambient too high.
Check cooling fan. Clean heat sink fins. Reduce ambient temperature.
Fan replacement required if failed.
Loss of communication from PLC or BMS. Fieldbus cable fault.
Check Profibus/Modbus/DeviceNet cable. Check PLC programme and communications settings.
If cable and PLC are healthy, drive fieldbus card may have failed.
Output short circuit, earth fault, inertia too high for ramp setting, motor cable too long.
Check output cable and motor insulation. Increase acceleration ramp time. Check motor sizing.
If no external fault found after insulation check, suspect IGBT fault.
Cooling fan failed, blocked vents, high ambient.
Check internal cooling fan. Clean air vents.
Fan part numbers from Schneider distributor. Do not operate with failed fan.
Motor current exceeded rated value persistently. Mechanical overload or incorrect motor parameters.
Check motor rated current entered in drive parameters. Check driven load for obstruction.
If motor current is correct and fault persists, motor may have winding damage — check winding resistance.
Supply phase missing at drive input.
Check all three input phases and fuses.
Do not restart on single-phase supply.
Low supply voltage, phase loss.
Measure all three input phase voltages at drive terminals.
Persistent on healthy supply — internal fault.
Supply voltage too high. Check supply with meter.
Measure incoming supply. If above drive rated voltage, investigate supply issue.
Do not operate if supply consistently above upper limit.
Short circuit between U output and earth or between phases.
Disconnect motor cable. Measure insulation phase-to-earth and phase-to-phase.
Confirmed short — motor or cable replacement required.
Earth fault on motor winding or output cable.
Measure insulation motor and cable to earth.
Below 1 MΩ — isolate and repair before restart.
Parameter configuration incorrect or incompatible settings combination.
Review parameter settings. Factory reset and re-commission if required.
Contact engineer if unsure which parameters are causing conflict.
Memory corruption. Possible after power interruption during parameter save.
Factory reset and re-enter all parameters.
Repeated EEPROM faults — control card replacement may be required.
Acceleration time too short, load inertia too high, motor fault.
Increase acceleration time (Pr.7). Check motor for mechanical seizure.
If fault persists with longer ramp, check motor winding and cable insulation.
Sudden load spike, output short, earth fault.
Measure output cable and motor insulation. Check process for load spikes.
IGBT damage possible if overcurrent was severe — do not restart without insulation check.
Deceleration too fast, regenerative load.
Increase deceleration time (Pr.8). Consider braking resistor if load has high inertia.
Repeated OC3 without change — braking resistor selection and connection check required.
Supply voltage high, regen from load during acceleration.
Check supply voltage. Reduce acceleration rate.
Consistent OV1 — check supply quality and consider line reactor.
Supply voltage spike, regen load.
Check supply quality with power analyser.
If supply is clean, braking resistor may be required.
Deceleration too fast for load inertia, no braking resistor.
Increase deceleration time. Verify braking resistor connection and resistance value.
If braking resistor has failed open, replace before restart.
Cooling fan fault, blocked vents, ambient too high.
Check cooling fan. Clean heat sink. Reduce panel ambient.
Fan failure — replace fan before resuming operation.
Motor running above rated current, motor thermal model tripped.
Check motor load. Verify motor rated current (Pr.9) set correctly.
If motor is physically hot, allow full cooldown before restart.
Drive heatsink exceeded temperature limit.
As E.THT — check cooling fan and ambient.
Fan replacement required.
Earth fault on output cable or motor winding.
Measure insulation resistance all output phases to earth.
Below 1 MΩ — motor or cable repair required before restart.
One input phase missing.
Check all three input phases, fuses, and upstream contactor.
Do not restart on single-phase supply.
Output short circuit, ground fault, acceleration too fast, motor cable fault.
Check output insulation. Increase accel time (C1-01). Check motor and cable.
Repeated oC with no external fault — IGBT suspect.
Decel too fast, supply overvoltage, regenerative load.
Increase decel time (C1-02). Check supply voltage. Verify braking resistor.
Braking resistor selection review required if regen load is frequent.
Low supply voltage, phase loss, momentary supply interruption.
Check three-phase supply and incoming fuses.
Persistent uv1 on good supply — internal fault.
Internal control power supply fault.
Cycle power. Check for external causes (earthing issues, voltage spikes).
Persistent fault — control board failure, contact engineer.
Cooling fan failed, blocked vents, ambient too high.
Check cooling fan. Clean vents. Reduce ambient.
Fan replacement required if failed.
Motor current exceeded motor overload protection threshold.
Verify E2-01 (motor rated current) is set correctly. Check driven load for mechanical issue.
If motor is running hot and overloaded, investigate load and motor sizing.
Drive current exceeded 110% for one minute (ND) or 150% instantaneous.
Check actual output current vs drive rating. Check for load spikes.
Drive may be undersized for application — review with engineer.
Ground fault on output phases. Motor or cable insulation breakdown.
Measure insulation resistance motor and cable to earth.
Insulation below 1 MΩ — do not restart.
Internal control circuit hardware fault.
Cycle power. Check earthing quality.
Persistent CPF fault — control board failure, contact engineer.
External fault input active — interlock opened.
Check external fault input wiring (TB3 terminals). Identify which interlock is open (E-stop, thermal switch, door switch).
Do not bypass interlocks without identifying cause.
DC bus voltage dropped below minimum — supply phase loss, supply interruption.
Check all three incoming phases and fuses.
Do not restart until supply confirmed healthy.
DC bus below minimum threshold.
Check incoming supply voltage.
If supply is in spec, internal capacitor or rectifier fault possible.
DC bus above maximum — decel too fast, regen load, high supply voltage.
Increase decel time. Check supply voltage. Verify braking resistor.
Review braking resistor sizing if application is regen-heavy.
Motor stalled or speed not reached within timeout period.
Check driven load for mechanical seizure or excessive load. Verify motor is not running against closed valve/damper.
Mechanical investigation required if load is seized.
Motor I²t overload tripped.
Check motor rated FLA entered in drive parameters. Verify driven load.
Investigate load and motor sizing if fault repeats.
Drive overheating — cooling fan fault, blocked vents, high ambient.
Check cooling fan. Clean heatsink vents.
Replace fan if failed.
Hardware overcurrent detected — typically output short or earth fault.
Disconnect motor. Measure insulation resistance. Check output cable.
If IGBT damage suspected (no external cause), do not restart — contact engineer.
Ground fault on output or motor.
Measure insulation resistance motor and cable to earth.
Below 1 MΩ — repair required before restart.
4–20 mA reference signal lost (dropped below 2 mA).
Check reference signal source. Check cable from PLC or sensor.
If source is healthy, check drive analogue input setting and wiring.
Output short circuit, earth fault, aggressive acceleration.
Check output cable and motor insulation. Increase acceleration ramp.
Persistent fault with no external cause — IGBT inspection required.
Cooling fan blocked or failed. High ambient.
Check cooling fan. Clean vents.
Fan replacement required if failed.
Decel too fast, regen load, high supply.
Increase decel ramp. Check supply voltage. Check braking resistor.
If braking resistor is open circuit, replace before restart.
Low supply voltage, phase loss.
Check all three input phases and fuses.
Persistent on good supply — internal fault.
Motor running above rated current. Mechanical overload.
Verify motor rated current in P0401. Check driven load.
Repeated trips under normal load — investigate motor and load sizing.
One phase missing at drive input.
Check three-phase supply and upstream protection.
Do not restart until all three phases confirmed.
Earth fault on output cable or motor.
Measure insulation resistance to earth.
Below 1 MΩ — do not restart.
Supply overvoltage, deceleration too fast, regenerative load.
Check supply voltage. Increase deceleration ramp time (P1-04).
Braking resistor required if load is regenerative.
Low supply voltage, phase loss.
Check all supply phases and fuses.
Persistent on healthy supply — internal fault.
Cooling fan blocked or failed, high ambient.
Check cooling fan. Clean heatsink vents.
Fan replacement required.
Output short circuit, earth fault, aggressive acceleration.
Check motor and cable insulation. Increase acceleration ramp (P1-03).
No external fault found — internal IGBT suspect.
Motor current exceeds overload threshold. Mechanical overload.
Verify motor rated current in P1-08. Check load.
Motor or drive undersized — review specification.
External fault input has been activated.
Check wiring on digital input configured as external fault. Identify which device triggered it.
Do not bypass — identify cause of interlock trip.
Motor has lost its load (e.g. broken belt, pump cavitation, coupling failed).
Check mechanical connection between motor and load. Check for pump cavitation.
If belt or coupling is broken, mechanical repair required before restart.
Analogue reference signal below 2 mA — cable fault or source failure.
Check signal source and cable. Confirm PLC output is active.
If source is healthy, check drive analogue input wiring.
Not all drive problems raise a fault code. These operational symptoms frequently require engineer attendance:
| Symptom | Likely Cause | First Check |
|---|---|---|
| Drive powers up but won't run | No run command, interlock open, control signal missing | Check digital input status on drive display. Confirm 24V run signal present. |
| Motor runs but at wrong speed | Reference signal fault, parameter incorrect, PID setpoint issue | Check analogue input value on drive display. Confirm 4–20 mA signal from sensor/PLC. |
| Motor runs in wrong direction | Output phases U/V/W swapped, motor wiring reversed | Swap any two output phases (U↔V) at drive output terminals — do not swap at motor. |
| Drive trips intermittently under load | Thermal overload, loose connection, supply quality issue | Monitor drive output current display under load. Check all power terminal torques. |
| Drive display blank, no power | Incoming fuse or MCB blown, control supply fuse failed, SMPS fault | Check incoming fuses. Measure voltage at drive input terminals L1/L2/L3. |
| Motor vibrates or makes noise at certain speeds | Skip frequency not set, resonance in mechanical system | Programme skip frequency bands in drive parameters to avoid resonant speeds. |
| PLC loses comms with drive | Fieldbus cable fault, address mismatch, termination resistor missing | Check Profibus/Modbus cable. Verify drive node address matches PLC configuration. Check termination. |
Ashmit Engineering Ltd provides VSD fault diagnosis, repair, and recommissioning across UK industrial and marine sites. We work with all major drive manufacturers.