Could Vacuum Contactor cause motor failure?

[TestBeforeTouch]

About a month ago I replaced an old 2300 volt oil immersed motor starter lineup with new vacuum contactor starters. One of the motors has since failed to ground and I was wondering if the failure could have occurred because of a transient caused by the fast interrupting time of the vacuum contactor and the long motor lead length. The motors are about 1 mile from the starters and are 125HP submersible well pumps.

 

[davidbeach]

Could well be. A bit of chop from the vacuum contactor, a bit of capacitance from an underground line, and a nice bit of transient overvoltage along with some old, weak, insulation and motor failure is not terribly unexpected. Since you imply other motors with the same configuration, I would suggest surge arresters at the motors (or as close as practicable).

 

[jraef]

This has been discussed several times in this forum in the past. A Keyword Search might prove helpful.

Eng-Tips: Help for your job, not for your homework Read faq731-376