Alarm guide · Yaskawa · Updated October 2026
Yaskawa A.510 alarm: overspeed
Yaskawa A.510 is an overspeed alarm: the motor speed went above the maximum. Check the command, motor wiring and the encoder.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
What the alarm means
The drive measured motor speed above its limit and stopped. Alarm numbers and wording can differ between series, so confirm with the manual for your unit.
Common causes
- Command or setting too high
- Overshoot from aggressive gains
- Motor phase wires connected in the wrong order
- Encoder or cable fault
- Vertical axis falling with a faulty brake
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.
- Note the exact alarm code and when it appears: at power-up, at start, or under load.
- Power off and turn the shaft by hand if safe: it should turn smoothly.
- Check the motor cable, encoder cable and connectors for damage and loose contacts.
- Check what changed recently: load, speed, settings, cables or a replaced part.
When to send it for repair
With correct wiring and settings, an encoder fault is a likely cause. Bench test the motor.
We test every motor on our Universal Servo Motor Repair Equipment, which reads and aligns the feedback and runs the motor under load without the original drive.
See Yaskawa servo motor repair, Yaskawa encoder repair and Yaskawa servo drive repair.
Questions
Does A.510 always mean the motor ran too fast?
No. A faulty encoder can send wrong speed data.
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.