Yaskawa A1000 AL-09 — What It Means
The code AL-09 does not appear in Yaskawa’s official A1000 VFD fault documentation. This code likely represents a misidentification. If you see AL 9 or Err 9, you may have a Danfoss drive, where it indicates inverter overload (the drive is operating near maximum current capacity). If you have a Yaskawa A1000 with an encoder feedback problem, the correct fault codes are PGD (Encoder Fault), PGL (Encoder Loss), or PGF (Encoder Error), depending on your option card and firmware version.
Before proceeding with any repair, verify the exact brand and model of your drive and double-check the displayed fault code. Consult your owner’s manual or the label on the drive itself. Misidentifying the drive brand or fault code can lead to unnecessary parts replacement and wasted diagnostic time.
Before You Replace Anything
Technicians sometimes replace encoder cables or option cards when the fault code is misread. Always verify the exact fault code on the VFD display and confirm the drive brand before ordering parts.
Common Causes
- Wrong drive brand identified (~40%) AL-09 is a Danfoss fault code, not Yaskawa, and appears when the inverter is overloaded.
- Fault code misread (~30%) The display may show a different code (like PGD or PGL on Yaskawa) that was transcribed incorrectly.
- Encoder feedback fault on Yaskawa (~20%) If the actual issue is encoder signals not reaching the VFD, the correct Yaskawa code is PGD, PGL, or PGF.
- Outdated or incorrect manual (~10%) The fault list in an old manual may not match your firmware version or option card configuration.
Quick Diagnosis
Answer these to narrow it down fast.
Does the drive nameplate say Danfoss (not Yaskawa)?
No: Confirm the drive is Yaskawa A1000 and write down the exact fault code displayed.
Does the display show PGD, PGL, or PGF (not AL-09)?
No: Look up the exact code in your A1000 manual or contact Yaskawa technical support for clarification.
Is the motor mechanically overloaded or binding?
No: The fault is likely electrical. Inspect power boards, IGBTs, input fuses, and DC link capacitors.
Step-by-Step Fix
- Stop the drive immediately and record the exact fault code, brand, and model number from the nameplate and display.
- Consult your drive’s manual or wiring diagram to confirm the meaning of the code for your specific brand and firmware version.
- If you have a Danfoss drive with AL 9, reduce motor load, inspect for mechanical binding, and check parameter 128 (Motor Thermal) settings.
- Test input fuses and rectifier diodes on the power board. Replace any blown fuses or shorted diodes.
- Inspect IGBT modules on the inverter board for shorts between collector and emitter. Replace failed modules.
- Measure DC link capacitors for capacity and ESR. Replace any bulging or weak capacitors.
- If you have a Yaskawa A1000 with encoder faults (PGD, PGL, PGF), inspect encoder cable connections, verify encoder power supply voltage, and reseat the encoder option card.
Parts Often Needed
| Part | Notes |
|---|---|
| Input fuse (Danfoss drives) | Amazon | Consult your drive’s datasheet for amperage rating |
| IGBT module (Danfoss inverter board) | Amazon | Match module type to your drive model and power rating |
| DC link capacitor (Danfoss power board) | Amazon | Large electrolytic, typically 400-450 V rated |
| Encoder cable (Yaskawa A1000) | Amazon | Shielded cable, verify pin count and connector type |
When to Call a Pro
Call a qualified drive technician or electrical engineer when you cannot confirm the drive brand, the fault code does not match any entry in your manual, or you need to test high-voltage components like IGBT modules, rectifiers, or DC link capacitors. If the drive is part of a critical production line or life-safety system, do not attempt repair without proper training and lockout/tagout procedures. A technician can also verify encoder option card configuration, measure DC bus voltage under load, and diagnose intermittent faults that do not appear during static tests.
Rough cost: A pro service call runs about $200-500.