Alarm guide · Yaskawa · Updated October 2026
Yaskawa A.410 alarm: undervoltage
Yaskawa A.410 is an undervoltage alarm: the main circuit voltage fell below the allowed level. Check the incoming supply, wiring and the drive.
By Suresh Sankaran, founder of Star Automations, servo motor repair since 1998.
What the alarm means
The drive saw the DC bus voltage drop below its limit. Alarm numbers and wording can differ between series, so confirm with the manual for your unit.
Common causes
- Low or unstable supply, momentary dips
- Loose or burnt terminal
- Main contactor or inrush circuit fault
- Aged bus capacitors
- Phase loss on the supply
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
Not usually the motor. If it repeats on a good supply, the drive needs repair.
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
Can a power dip cause A.410 once?
Yes. A single occurrence after a dip is normal. Repeated alarms need investigation.
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.