What each VFD fault code means across Siemens, ABB, Schneider, Mitsubishi, Yaskawa and Danfoss drives, what usually causes it, and the routine checks that prevent it.
Right now
Your VFD is showing a fault. What to do first
- 01Write down the exact code on the display, and what the machine was doing when it tripped: starting, running, slowing down or stopping.
- 02Check the drive's fault history if your keypad shows one. A code that has appeared several times before tells a very different story from a first trip.
- 03Reset once. If it trips again straight away with the same code, stop resetting: repeated resets on an overcurrent or earth fault can turn a cable problem into a destroyed drive.
- 04Look for the obvious: a jammed conveyor or pump, a burnt smell, a loose or scorched cable at the motor, a panel fan that has stopped.
- 05Don't open the drive or touch its terminals. The DC bus stays charged for minutes after power is switched off.
01 / The device
What a VFD fault code tells you
A variable frequency drive watches its own currents, voltages and temperatures thousands of times a second. When one goes outside a safe limit, the drive switches its output off to protect itself and the motor, and shows a fault code. The code tells you which protection tripped. It does not tell you why, and that difference is where most wasted time on a VFD goes.
Every manufacturer protects against the same handful of conditions, but each names them differently: the overcurrent trip that a Schneider drive shows as OCF appears as 2310 on an ABB, E.OC2 on a Mitsubishi and oC on a Yaskawa. The table below maps the common faults across six brands, and the sections after it explain what causes each one and how to keep it from returning.
How a VFD (Variable Frequency Drive) works →02 / Regular issues
The problems that come up most
What operators and maintenance teams actually report, before anyone has looked at a code.
Keeps tripping
The same fault returns after every reset, often at the same point in the cycle: starting, stopping or under full load.
Causes & checks →Drive on, motor won't run
The display is alive and shows no fault, but the motor never turns: usually a missing run permissive, a speed reference of zero, or an open output.
Causes & checks →Motor running hot on the drive
A self-cooled motor run for long periods at low speed loses most of its fan cooling, so it overheats at a load it handled fine across the line.
Causes & checks →Dead display, no power-up
Blown input fuses, a failed pre-charge circuit or a failed internal power supply. Do not keep re-energising it: a shorted input stage can do more damage each time.
Speed hunting or unstable
Wrong control mode for the load, untuned speed loop, a loose analogue speed reference, or electrical noise on the reference cable.
Upstream earth-leakage breaker tripping
Drive EMC filters and long motor cables leak current to earth by design. A standard RCCB upstream will trip on it; the protection has to be rated for drive loads.
03 / Error codes
Error codes by brand
The same fault, as each manufacturer displays it. A blank cell means we have not confirmed that brand's code, not that the drive lacks the protection.
| Fault | Siemens | ABB | Schneider | Mitsubishi | Yaskawa | Danfoss |
|---|---|---|---|---|---|---|
| Overcurrent | F30001 | 2310 | OCF | E.OC1 / E.OC2 / E.OC3 | oC | Alarm 13 |
| DC bus overvoltage | F30002 | 3210 | ObF | E.OV1 / E.OV2 / E.OV3 | ov | Alarm 7 |
| Undervoltage | F30003 | 3220 | USF | E.UVT | Uv1 | Alarm 8 |
| Drive overtemperature | F30004 | 4210 | OHF | E.FIN | oH | Alarm 29 |
| Motor overload | — | — | OLF | E.THM | oL1 | Alarm 10 |
| Drive overload | F30005 | — | — | E.THT | oL2 | Alarm 9 |
| Earth fault | F30021 | 2330 | — | E.GF | GF | Alarm 14 |
| Input phase loss | F30011 | 3130 | PHF | — | PF | Alarm 4 |
| Output phase loss | — | 3381 | OPF | E.LF | LF | — |
Overcurrent
Output current went above the drive's hardware trip limit, usually in a few milliseconds. The drive shut off its transistors before they could be destroyed.
Usual causes
Acceleration ramp too short for the load's inertia, a short or earth fault in the motor or cable, a mechanical jam, wrong motor data in the parameters, or starting into a motor that is still spinning.
Siemens F30001 · ABB 2310 · Schneider OCF · Mitsubishi E.OC1 / E.OC2 / E.OC3 · Yaskawa oC · Danfoss Alarm 13
Can't clear it? Send us the code →DC bus overvoltage
The voltage on the drive's internal DC bus rose above its limit. Energy is flowing back from the motor into the drive faster than the drive can get rid of it.
Usual causes
Deceleration ramp too short on a high-inertia load such as a fan or flywheel, an overhauling load like a lowering hoist or a downhill conveyor, a missing or failed braking resistor, or high or surging supply voltage.
Siemens F30002 · ABB 3210 · Schneider ObF · Mitsubishi E.OV1 / E.OV2 / E.OV3 · Yaskawa ov · Danfoss Alarm 7
Can't clear it? Send us the code →Undervoltage
The DC bus fell below the minimum the drive needs to run. The drive stops rather than run with an unreliable supply.
Usual causes
Supply dips, DG changeover, a loose or burnt input terminal, one blown input fuse, a failing pre-charge circuit, or ageing DC bus capacitors that can no longer hold the bus up under load.
Siemens F30003 · ABB 3220 · Schneider USF · Mitsubishi E.UVT · Yaskawa Uv1 · Danfoss Alarm 8
Can't clear it? Send us the code →Drive overtemperature
The heatsink or power module is too hot. The drive trips before its transistors exceed their temperature rating.
Usual causes
Dust-packed heatsink fins, a failed or slowing cooling fan, a hot panel with blocked or missing ventilation, high ambient temperature, or sustained running near the drive's current limit.
Siemens F30004 · ABB 4210 · Schneider OHF · Mitsubishi E.FIN · Yaskawa oH · Danfoss Alarm 29
Can't clear it? Send us the code →Motor overload
The drive's thermal model of the motor says the motor has carried too much current for too long. This protects the motor, not the drive.
Usual causes
A genuine mechanical overload or dragging bearing, the motor rated current set wrongly in the parameters, or a self-cooled motor run for long periods at low speed.
Schneider OLF · Mitsubishi E.THM · Yaskawa oL1 · Danfoss Alarm 10
Can't clear it? Send us the code →Drive overload
The drive itself has carried more than its rated current for longer than its overload rating allows. Different from overcurrent, which is instantaneous.
Usual causes
A drive sized too small for the load, a heavy-duty load on a drive rated for normal duty, or repeated starts on a high-inertia machine.
Siemens F30005 · Mitsubishi E.THT · Yaskawa oL2 · Danfoss Alarm 9
Can't clear it? Send us the code →Earth fault
Current is leaking from the output to earth. The drive has detected that the three output currents no longer add up to zero.
Usual causes
Motor winding insulation breaking down, a damaged or crushed motor cable, moisture in the motor terminal box, or very long motor cables with high capacitance to earth.
Siemens F30021 · ABB 2330 · Mitsubishi E.GF · Yaskawa GF · Danfoss Alarm 14
Can't clear it? Send us the code →Input phase loss
One of the three incoming phases is missing or badly unbalanced, detected as excess ripple on the DC bus.
Usual causes
A blown input fuse, a loose or burnt incoming terminal, a failed contactor pole upstream, or a single-phasing supply.
Siemens F30011 · ABB 3130 · Schneider PHF · Yaskawa PF · Danfoss Alarm 4
Can't clear it? Send us the code →Output phase loss
One of the three output phases to the motor is open.
Usual causes
A broken motor cable, a loose terminal in the motor box, an open contactor or isolator between drive and motor, or an open motor winding.
ABB 3381 · Schneider OPF · Mitsubishi E.LF · Yaskawa LF
Can't clear it? Send us the code →04 / General causes
Why these faults happen
Most codes trace back to a handful of root causes. Fix these and most trips stop.
Heat and dust
The biggest single cause on Indian shop floors. Cotton fibre, flour, cement and metal dust pack heatsinks, and panels in hot bays run well above the drive's rated ambient in summer.
Supply quality
Voltage dips, DG changeovers, unbalanced phases and switching surges all show up as undervoltage, overvoltage and phase-loss trips.
Parameters that don't match the job
Ramps set too short, motor nameplate data never entered, or a control mode chosen for a pump on a machine that needs constant torque.
Problems on the motor side
Ageing motor insulation, cable damage and mechanical jams are reported by the drive, but the fault is not in the drive.
Wear parts reaching end of life
Cooling fans and DC bus electrolytic capacitors wear out with running hours and heat. A rule of thumb for electrolytics is that every 10 °C hotter roughly halves their life.
Moisture
Monsoon humidity and condensation in panels that are switched off overnight lead to earth faults and tracking on the drive's boards.
05 / Prevention
How to prevent them
A routine any maintenance team can run. None of it needs special tools beyond a meter and a thermal camera.
Weekly
- 01Check that the panel cooling fans are running and the filters are not visibly clogged
- 02Look at the drive's fault history for new warnings, even if nothing has tripped
- 03Listen for a noisy or slowing heatsink fan
Monthly
- 01Clean or replace panel air filters
- 02Measure the panel's internal temperature during the hottest part of the day
- 03Check the incoming voltage on all three phases for imbalance
Every 6–12 months
- 01With the drive isolated and the DC bus confirmed discharged, blow out the heatsink and re-torque the power terminals
- 02Thermal-scan the power connections under load to catch a loose terminal before it burns
- 03Megger the motor and cable with the drive disconnected, and log the reading to spot a downward trend
- 04Back up the parameter set, so a replacement drive can be configured in minutes
- 05Replace cooling fans and check capacitor health against the manufacturer's maintenance schedule
Safety
The DC bus stays charged after the supply is switched off. Wait for the discharge time printed on the drive and confirm zero volts with a meter before touching the terminals. Never megger a motor with the drive still connected: the test voltage will destroy the drive's output stage.
Getting it fixed
When the VFD needs a technician
If the fault keeps coming back, or the drive won't power up at all, it needs someone with test equipment on site. MachineryFix sends drive technicians to factories across Hyderabad and Telangana. Send the code and a photo of the display first, and the technician arrives knowing what to look for.
On site they work out whether the fault is in the drive, the motor or the cable between them, repair it, and run the machine with you before signing off the job card.
VFD repair near me →06 / Questions
Questions people ask
How do I reset a VFD fault?+
Most drives reset from the keypad's stop/reset key, a reset input on the terminals, or by removing power until the display goes dark. But a reset only clears the code. If the cause is still there, the fault returns, and repeatedly resetting an overcurrent or earth fault can turn a cable problem into a failed drive. Note the code and the moment it tripped before resetting.
What is the difference between an overcurrent and an overload fault?+
Overcurrent is instantaneous: current spiked past the hardware limit in milliseconds, usually from a short, an earth fault or a ramp that is far too fast. Overload is cumulative: current stayed above the rating for too long, usually from a mechanical load the motor or drive is too small for. They point to different causes, so the distinction matters.
Why does my VFD trip only when the DG set is running?+
DG supplies dip harder when a large load starts, can drift in frequency and voltage, and are often slightly unbalanced. Drives see this as undervoltage or phase-loss trips. Check the DG's voltage and frequency during the load step, and the drive's undervoltage and phase-loss settings.
Can a VFD damage a motor?+
It can stress one. The drive's fast switching creates voltage spikes at the motor terminals, worse with long cables, which can wear older winding insulation. It can also drive currents through the motor bearings, leaving a frosted or fluted track. Inverter-duty motors, shorter cables or output filters and good earthing prevent both.
How long does a VFD last?+
The power electronics can last many years. The cooling fans and DC bus capacitors are wear parts, and heat decides how fast they go. A drive kept cool, clean and with its fans changed on schedule usually outlives one in a hot, dusty panel by a wide margin.
What should I ask before choosing someone to look at a failed VFD?+
Ask whether they will test the motor and cable as well as the drive, since many drive faults start outside it. Ask whether a repaired drive is tested under load before it is returned, and whether you will get a written note of what failed and why. Our VFD repair near me page explains how MachineryFix approaches this.
My VFD is showing a code that isn't listed here. What should I do?+
Note the exact code, the drive's make and model from the rating plate, and what the machine was doing when it tripped. The manufacturer's manual lists every code for that model. If you can't find it or can't clear it, send the code and a photo of the display to MachineryFix on WhatsApp and a drive technician will tell you what it points to.
07 / Related
Where to go next
Written & reviewed by MachineryFix — last reviewed — questions? Call +91 70133 33007