Yaskawa A1000 AL-14 Fault — What It Means
The AL-14 fault code does not exist in Yaskawa A1000 VFD documentation. This alarm is specific to Danfoss VFDs (such as the FC series) and indicates a ground fault or earth fault, meaning current is leaking from the output phase to ground through damaged motor cable insulation or a motor winding fault. Yaskawa A1000 drives use different fault codes, typically prefixed with oC (overcurrent), Uv (undervoltage), oH (overheat), CPF (CPU faults), or UV3 (DC bus issues). If you see what appears to be AL-14 on a Yaskawa drive, verify the drive brand and model on the nameplate and consult the operator display for the actual fault code.
For true Yaskawa A1000 ground-fault-related issues, look for codes like oC (overcurrent at startup or during run) or UV3 (DC bus undervoltage), which can indicate output short circuits or motor problems. The Yaskawa A1000 manual (document C710616) provides complete fault code definitions. If your drive is actually a Danfoss unit showing AL-14, the fault points to insulation breakdown in the motor cable or motor windings allowing current to leak to ground.
Before You Replace Anything
Technicians sometimes replace the entire VFD when seeing unfamiliar codes without confirming the drive brand. Always verify the nameplate manufacturer and consult the correct manual before ordering parts.
Common Causes
- Wrong drive brand identified (~40%) AL-14 is a Danfoss code, not Yaskawa, so the drive may be mislabeled or the code misread.
- Damaged motor cable insulation (if Danfoss) (~25%) Cuts, abrasions, or degraded insulation in the motor cable allow current to leak to ground.
- Motor winding ground fault (if Danfoss) (~20%) Internal motor winding insulation has failed, creating a path to the motor frame.
- Incorrect wiring or grounding (if Danfoss) (~10%) Miswired phase connections or improper grounding create a fault path.
- Gate driver or IGBT failure (if Danfoss) (~5%) Failed current sensor or shorted IGBT on the output stage triggers false ground fault detection.
Quick Diagnosis
Answer these to narrow it down fast.
Does the drive nameplate say Danfoss or Yaskawa?
No: Check the operator display again and photograph the exact code, then consult the manual for your confirmed drive model.
Is the motor cable visibly damaged or pinched?
No: Test motor and cable insulation resistance with a megohmmeter (readings below 1 MΩ indicate a ground fault).
Does the fault clear when you disconnect the motor cable from the drive?
No: The fault is likely internal to the drive (gate driver, IGBT, or current sensor). Call a VFD technician or drive repair center.
Step-by-Step Fix
- Power down and lock out the VFD and disconnect it from the supply to work safely.
- Verify the drive brand by reading the nameplate on the front or side of the enclosure. Confirm whether it is Yaskawa A1000 or Danfoss FC series.
- Photograph the operator display showing the exact fault code and compare it to the manual for the confirmed drive model.
- Inspect the motor cable from the VFD output terminals to the motor junction box for cuts, abrasions, conduit chafing, or insulation damage.
- Disconnect the motor cable at the VFD output terminals (T1, T2, T3 or U, V, W) and clear the fault. If the fault does not return, the problem is downstream.
- Test insulation resistance with a megohmmeter set to 500V or 1000V. Measure from each motor lead to ground and from each motor winding to the motor frame. Readings below 1 MΩ indicate a ground fault.
- Replace the motor cable if insulation resistance is low on the cable, or replace the motor if the fault is in the windings. If the fault persists with the motor disconnected, contact a VFD repair specialist to test gate driver and IGBT circuits.
Parts Often Needed
| Part | Notes |
|---|---|
| Motor cable (3-conductor shielded VFD-rated) | Amazon | Use VFD-rated cable with proper gauge for the motor distance and horsepower. |
| 3-phase AC motor | Amazon | Match voltage, horsepower, and mounting to the application if motor windings are shorted to ground. |
When to Call a Pro
Call a qualified VFD technician or industrial electrician if the fault persists after disconnecting the motor, if you lack a megohmmeter to test insulation resistance, or if internal drive components (gate driver board, IGBTs, current sensors) are suspected. High DC bus voltages (typically around 580V DC for 400V AC line input) and complex power electronics make internal VFD repair dangerous without proper training and test equipment. A drive repair center can bench-test and replace gate driver boards or IGBT modules if the fault is internal. Always consult the correct manual for your confirmed drive brand and model before any repair work.
Rough cost: A pro service call runs about $200-800.