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woobster1
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Join Date: Jan 2009
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GE Contactor Line Load Reversal

01/10/2013 4:47 PM

I have a large compressor fitted with a GE Record Plus Moulded Circuit breaker FG600 marked line load. The breaker is marked line load but has been connected in reverse. All the protection circuits are on the load side which is currently connected to the line. The GE manual states this should not be fitted in reverse.

Other than the manufactures documentation stating this should not be fitted in reverse does anyone know of a reason why? These compressors have over a period of time suffered from nuisance trips.
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North of 60
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#1

Re: GE Contactor Line Load Reversal

01/10/2013 5:38 PM

Simply the way they are built. MCCBs that are designed to be fed from either end have special provisions in them for the current sensing elements.

Get them reversed. These units as installed currently do not afford the equipment the proper protection and are a fire hazard. Your insurance carrier would not pay on a loss on this equipment. Installing them wrong like this voids their certification.

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Yahlasit
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#2

Re: GE Contactor Line Load Reversal

01/10/2013 5:39 PM

Not sure if this is the reason, but all the current sensing and magnetic surge circuitry will remain energized even with the breaker in the OFF position.

This makes me think that an arc flash could be more destructive and dangerous to personnel.

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lyn
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#3

Re: GE Contactor Line Load Reversal

01/10/2013 5:57 PM

You're sure they are not reversing contactors"?
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kvsridhar
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#4

Re: GE Contactor Line Load Reversal

01/10/2013 9:22 PM

i was partially involved in the design of the Record+ MCCB design. It has a rotary break concept, and should normally not have Line/load polarisation. However, i have been retired for a long time, so don't know the present situation.

One must NOT reverse connect such a polarised device. One must connect line and load properly. The main reason is that, after interruption of a high fault current, the arc chamber which is somewhat ionised, can cause a restrike, which can destroy the breaker. A rotary break usually obviates this, but then, if GE has marked line/load....

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woobster1
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#5
In reply to #4

Re: GE Contactor Line Load Reversal

01/11/2013 1:05 AM

We have had one explode all ready, it was on removal of the remaining parts when line load markings were discovered.

Did find some information on a rotary break concept, unfortunately unable to find web site again?
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kvsridhar
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#7
In reply to #5

Re: GE Contactor Line Load Reversal

01/11/2013 10:50 AM

You may want to check out the patents of such a devce, here is one for exampl.....http://www.freepatentsonline.com/y2009/0002106.pdf

This patent may not be applicable to your device, still, it gives a lot of information. You can also search the patents of Schneider, which is also a rotary break MCCB.

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electrobrains
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#6

Re: GE Contactor Line Load Reversal

01/11/2013 2:49 AM

That is a specialised breaker, it is faulty now because someone did not follow manufacture instructions.

Replace it and connect new one as per manufacture instructions
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Paulusgnome
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#8

Re: GE Contactor Line Load Reversal

01/12/2013 11:02 PM

This seems a bit odd. The GE Record Plus MCCBs can all be fed from either end. The key to this is that the trip units are all powered from the CTs used to monitor line current, so it doesn't matter which end of the breaker is used for the feed, the trip unit gets power regardless. I would not expect the choice of feed end to result in nuisance trips, either.

I suggest that you call your MCCB supplier, tell him you are having nuisance-trip issues with one of his FG-framed breakers, and see what he says.

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woobster1
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#9
In reply to #8

Re: GE Contactor Line Load Reversal

01/13/2013 4:41 PM

This occurs on all seven items of equipment built the same.
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Paulusgnome
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#10
In reply to #9

Re: GE Contactor Line Load Reversal

01/13/2013 9:23 PM

Do you have any idea of the cause of the nuisnce trips?

Have you got the trip units on the breakers set correctly?

GE make two different trip units for that MCCB : the SMR1 and the SMR2. Which one do you have?

I know it seems unlikely, but if you have eliminated the obvious causes, you may have faulty MCCBs. Phone your supplier.

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Users who posted comments:

electrobrains (1); kvsridhar (2); lyn (1); North of 60 (1); Paulusgnome (2); woobster1 (2); Yahlasit (1)

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