Breaker Failure on 1000HP drive unit
Breaker Failure on 1000HP drive unit
(OP)
Here are some pics of the failure. What could cause this or what are some of the modes of failure?
Some information -
Its 480V main drive unit. The failure occurred on a model 140-R6 molded case circuit breaker.
The failure occurred on the line side between L2 and L3. The back of the input conductor was melted and the arc had actually melted and penetrated the sub panel.

Some information -
Its 480V main drive unit. The failure occurred on a model 140-R6 molded case circuit breaker.
The failure occurred on the line side between L2 and L3. The back of the input conductor was melted and the arc had actually melted and penetrated the sub panel.







RE: Breaker Failure on 1000HP drive unit
Some possible causes:
1. Loose connection on incoming wire causing overheating and eventual arcing actoss phase-phase.
2. Foreign material shorting across the incoming terminals or between one terminal and grounded metal.
3. Dust or moisture shorting out the terminal to ground.
4. Animal shorting out leads.
5. Voltage surge from outside casuing an arc across the insulation.
Could be many other things.
RE: Breaker Failure on 1000HP drive unit
RE: Breaker Failure on 1000HP drive unit
No pictures as rcwilson said, but in addition to what he mentioned what cable, size and quantity did you use for wiring the input (L2 and L3 means it was on the field connection side of the breaker) and how was it connected? Mechanical lugs, crimp lugs?
"Will work for (the memory of) salami"
RE: Breaker Failure on 1000HP drive unit
Best to you,
Goober Dave
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RE: Breaker Failure on 1000HP drive unit
Take a look at this cut sheet and let us know what terminating accessory was used, or if they maybe didn't use one.
"Will work for (the memory of) salami"
RE: Breaker Failure on 1000HP drive unit
Link
RE: Breaker Failure on 1000HP drive unit
RE: Breaker Failure on 1000HP drive unit
"Will work for (the memory of) salami"
RE: Breaker Failure on 1000HP drive unit
RE: Breaker Failure on 1000HP drive unit
"Will work for (the memory of) salami"
RE: Breaker Failure on 1000HP drive unit
I don't see any signs of overheating damage that would be caused by loose connections.
My guess would be contamination of some sort.
Is that breaker supposed to have some kind of insulating paper used under it?
RE: Breaker Failure on 1000HP drive unit
Sorry again if I stole your thread - no disreprect.
RE: Breaker Failure on 1000HP drive unit
Picture of aftermath
RE: Breaker Failure on 1000HP drive unit
RE: Breaker Failure on 1000HP drive unit
Thanks for you help guys!
RE: Breaker Failure on 1000HP drive unit
RE: Breaker Failure on 1000HP drive unit