Alarm guide · Delta · Updated October 2026
Delta AL001 alarm: Overcurrent
Delta ASDA AL001 means the main circuit current exceeded 1.5 times the drive's maximum instantaneous current. Causes include a short at the drive output, incorrect motor wiring, or a failed IGBT in the drive. Check the motor and wiring first.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
What the alarm means
Delta ASDA AL001 means the main circuit current exceeded 1.5 times the drive's maximum instantaneous current. Causes include a short at the drive output, incorrect motor wiring, or a failed IGBT in the drive. Check the motor and wiring first.
Safe first checks
General guidance only. Follow the drive manual and your site's electrical safety rules. Power off, and let the DC bus discharge, before touching connectors.
- Power off and wait for the drive to discharge.
- Check the U, V, W wiring order against the manual.
- Check the motor cable for shorts and exposed conductors.
- Test the motor insulation to earth.
When to send it for repair
Send the drive when the motor and wiring test good and the alarm stays after a power cycle. Send the motor too if its windings test bad.
See Delta servo motor repair, encoder repair and servo drive repair.
Questions
Can I clear the AL001 alarm and keep running?
Not safely until the cause is found. An overcurrent alarm that clears and returns can damage the drive further or burn the motor. Check the motor and cable first. If they test good and the alarm returns, the drive needs repair.
Is it the motor, the cable or the drive?
Swap with a known-good cable first, then swap the motor to another axis if you can. If the alarm follows the motor, send the motor. If it stays on the axis with a good motor and cable, send the drive. We test both when you are not sure.
How long does repair take?
Emergency repair is done the same day where the fault and parts allow, urgent in 3 working days and standard in 7 working days, counted from when the unit reaches our bench and the quote is approved. Every unit returns with a printed test report.
Can I get an exchange unit?
If we hold a matching unit, Servo Swap ships a tested exchange unit while yours is repaired. Mark "line down" on the request form and add the part number.
Brand names identify the units we repair. Star Automations is an independent multi-brand repair company and is not an OEM service centre.