Can someone offer advice on a recent, unwelcome discovery? The pump in our drinking water well just stopped working recently. It was then discovered that it had been incorrectly wired at 110 VAC and should have been running on 220VAC. (1/2 HP @ 5 gal/min positioned approx. 30' below ground) It survived under these conditions for several years (5+?)before malfunctioning. There, of course, is no well tag available. I can only theorize that having been immersed in water, it was able to disperse enough of its heat build up to continue working. Is it reasonable to believe that it has taken this long for the insulation to have failed to the point where it stalled? The work load finally equaled the slowly failing torque it could generate. The real mystery to me is why it now has begun working again after re-wiring it correctly, i.e. 220 VAC. What can I expect now? It must only be a matter of time (short term) when this pump will fail again. If insulation life is halved by every 10 degree C increase above ideal operating temps, this pump must be on its last legs. Specifically, what are the physics of this motor's operating conditions now that I've doubled the voltage? What's happening in there?

Much obliged,
Mickey

I guess the pump has been designed against unintended abuse.

I think that the initial pump was grossly over sized and there were at that time no adequate performance measures nor commissioning standards in place, since after 5+ years the installation error has been detected.

Motors are designed to run under adverse conditions and as long as we do not quantify and verify the output these issues will be undetected.

It all depends on how badly stator insulation (mainly ground insulation) has been affected due to running at elevated temperature. If phases are still balanced and ground insulation is still sound the motor will work for awhile but chances of failure have obviously increased.