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When a large breaker goes trip free do the mains close and then immediately open or try to close but not make then return to the open position. It happens so fast I can't tell
Thanks LC
 

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Discussion Starter · #3 ·
These are not residential breakers. They are draw out power breakers like Eaton VCPW, DS, GE Manga blast, AK and the like.
 

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What does the term "goes trip free" mean? The code use of the term "trip free" only means that you can physically lock the external handle in the on position, but that will not prevent the breaker from opening the circuit for an overcurrent condition.
 

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If the breaker is 'free of tripping', that means it won't open.... even when overloaded.
 

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Discussion Starter · #6 ·
When a power breaker has gone trip free the breaker has tried to close but it opens immediately not because of overcurrent but because of a a mechanical issue. The original question was do the main contacts close before it goes trip free. Trip free happens when you try to close the breaker.
 

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When a breaker is trip free the moving contacts do not change position.

The trip latch stays engaged so the closing spring discharges without ever actuating the drive arm, so the moving contacts never actually close onto the stationary contacts.

On a power circuit breaker, check all the interlocks connected to the trip latch. I often see cell interlocks get all jammed up because the breakers got thrown around, so these never release even when the breaker is properly racked and it keeps the breakers from closing.
 

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Discussion Starter · #8 ·
That is what I was looking for Thanks Big John. LC
 

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These are not residential breakers. They are draw out power breakers like Eaton VCPW, DS, GE Manga blast, AK and the like.
Just curious, what kind of work do you do Lone Crapshooter? I am apprenticing doing service and pm on the large draw out breakers and power distribution equipment. I got to work on a line up of 5kV magna blasts in the summer... you definitely know when they open :thumbup:
 

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Discussion Starter · #10 ·
I work in a in plant electrical distribution department. I have seen many breakers go trip free when doing RM but never had a good understanding what was going on when the breaker goes trip free.
 

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THE "BIG RED MACHINE"
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I work in a in plant electrical distribution department. I have seen many breakers go trip free when doing RM but never had a good understanding what was going on when the breaker goes trip free.
what kind of factory is it? Oil refinery, steel mill?
 

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Usually it means you haven't reset the trip unit since the last time it was tripped and it is still showing a flag (ie: overcurrent, ground fault)

Make sure you clear the trip unit before trying to reset the breaker
 

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When a large breaker goes trip free do the mains close and then immediately open or try to close but not make then return to the open position. It happens so fast I can't tell
Thanks LC
They can, depending on how it is being used, but in most cases the contacts are allowed to touch, then re-open. In fact it's required in cases where the 52a contacts are used to energize the trip coil. The only prohibition is that if you are holding the Trip command button manually, and a Close command is given, the main contacts are not allowed to touch. Makes sense if you think about it, you would piss your pants if the contacts closed into a fault that you KNEW was there and that's why you were holding the Trip button!

This is outlined in ANSI C37.04 by the way.
 
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They can, depending on how it is being used, but in most cases the contacts are allowed to touch, then re-open. In fact it's required in cases where the 52a contacts are used to energize the trip coil. The only prohibition is that if you are holding the Trip command button manually, and a Close command is given, the main contacts are not allowed to touch. Makes sense if you think about it, you would piss your pants if the contacts closed into a fault that you KNEW was there and that's why you were holding the Trip button!

This is outlined in ANSI C37.04 by the way.
Exactly. Thats the anti pump (Y) relay doing its job. :thumbup:
 

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These are not residential breakers. They are draw out power breakers like Eaton VCPW, DS, GE Manga blast, AK and the like.
Which one? While they all are designed to the same ANSI requirements they each acomplish this differently. Generally you either have a trip signal or something was not reset or you have an adjustment issue. If neither one of those is the cause you likely have worn or damaged parts in the mech, these breakers are designed with refirbishment in mind (Time or # of operations in tech manual). Wearable parts need replacement every now and then.
 
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