Thread: Now My Phase Converter Blew Up!

So after causing the motor on our Bridgeport to overheat by running it on an overpowered static phase converter, our Clausing lathe started making lound noises. The belts were shot and slapping all over the place, so I installed new ones. The belt-slap noise was gone, but there was still a very loud and unpleasant noise that sounded to me as though bearings were going. But this happened overnight, so I doubt it.

After running the lathe about 30 seconds with the loud noise and new belts, the Phase-a-matic 3-5 HP started smoking and dripping oil. And it was hot as heck. We turned off the power before it actually blew up or tripped the breaker.

So my question is: Which broke first? The lathe motor or the Phase-a-matic? Did I damage the phase converter by running a 1 HP mill on it? And this caused the motor in the lathe to run funky and loud? And this caused the converter to melt down?

Or is it possible that the lathe is shot? I want to get the power system fixed, but I don't want to installe a new 10HP rotary converter for a lathe that we can't afford to have fixed.

Thanks!

Possibly there was damage from the lower power load.... Could have been excessive voltages, or other issues that damaged internal parts.

OR it could have just gone bad. The inability to work with the 1HP could even have been an early symptom.....

Motors are pretty tough. If you can get the Clausing motor spinning and connect it to 1ph power (similar to pony motor or rope-starting an RPC) you can probably determine if it has a problem.

You might first make some resistance measurements to be sure there is nothing really grossly wrong with it. Shorted or grounded windings, etc.

I'll stick my neck out here. Excuse me if you already checked but... Could the motor on the spindle have been wired for 440? It would run slow- sort of, and get real hot, and pull the wrong current.

It's probably not wired for 440. We used it reliably last year about 6-7 times with no problems. It was hooked up about 10 years ago and the guy who did it was an experienced machinist who knew 3-phase pretty well.

About 2 years ago a new breaker box was installed and I have been told that a lower output phase converter was removed at the same time. I think this is where all the problems originated from.

Once we get a new rotary convertr hooked up (and confirm the motor has not been cooked), I will double check that it is wired properly.