Motors Dropping Out

[edko]

A problem lately has been motors dropping out without tripping breakers and no legitimate reason. The obvious is to test relays and breaker settings and applying a monitor on to the line. We have not done a lot of maintenance in the past three years. Can there be issues with loose wiring causing these intermittent problems? Any suggestions on other things that can be checked?

 

[waross]

HP's?
Voltages?
Applications?
Control scheme?
Loose mounting bolts?


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[PHovnanian]

Dropping out how? If the breakers aren't tripping, all that's left would be the contactors. Check the control wiring, particularly anything common to all of the affected motors.

 

[jraef]

I agree, The very first thing to do is determine what is "dropping out".


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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[waross]

We had a 600 KW generator-end drop out once. A combination of bad crating and bad rigging. If it had been much higher it may have gone right through the bottom of the old tramp freighter. It was being returned after being sent out for cleaning, dipping and baking. The flat copper windings shifted and cut the insulation. It went back for a rewind.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

I had an MCC drop out once. Arrived on the job site a day ahead of schedule, so there was no fork lift. The truck driver had another delivery to make and got impatient. He tried to move it to another truck with a powered lift gate. But their beds ere different heights and in the process of moving it to the edge of his bed, he wobbled it too much and it fell off his truck, hit the other truck's tailgate, flipped back up, smashed against his again and then hit the ground. The second truck driver panicked and drove forward, so the MCC then fell on its face in the mud. Needless to say there was little in there that was salvageable, but the trucker's insurance adjuster wanted us to energize it to see how much damage there was. I had a difficult time convincing him that was a really bad idea...


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[LionelHutz]

We had some enclosures dropped out of a truck at the wrong address. I think it might have been a Tim Horton's. The driver must have been a real ass. I don't know if the address was wrong or if he just couldn't find the place but the owner of the store called after finding the shipping info on the crates laying in his yard.


On a more serious note. Instead of posting here looking for a "quick fix" answer, the time has come to actually start doing preventative maintenance.