Trip and close coil for power breakers
Trip and close coil for power breakers
(OP)
Hey guys,
Do all power breakers have separate trip and close coils? and is there any difference between main breaker and feeder breaker in this regard?
Any link would be appreciated!
Do all power breakers have separate trip and close coils? and is there any difference between main breaker and feeder breaker in this regard?
Any link would be appreciated!






RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
I thought all MV's have trip and close coils and I was wondering about LV breakers.
I am working on a Battery sizing for a petrochem and previous engineers have accounted for trip coils which made me to wonder why close is missing?
RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
At a recent substation I worked on, the worst case DC voltage was for a bus trip following a breaker closing. In this case, the DC motor would be still be charging the closing spring when the bus lockout activated all of the trip coils.
RE: Trip and close coil for power breakers
1- Do you mean close or trip in this sentence?
Some MV breakers use AC and some use DC for close coils. Also some MV and HV breakers use AC for charging up the spring/hydraulic mechanism.
2- "An incoming breaker should not be designed to need AC for closing" is there any reason for this?
RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
These are for MV and HV breakers and in LV we don't need close coil (spring charging coil) right?
RE: Trip and close coil for power breakers
Otherwise the summary from davidbeach is quite accurate.
If there's no requirement for any automated breaker closing (OH&S / arc flash / safety requirements notwithstanding) then trip coils can be provided so that remote means of tripping the breaker can be used, but manual intervention is required to reclose the breaker.
RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
I would imagine a petrochem would have lots of these. I haven't seen DC solenoids for this application, but I imagine they exist.
RE: Trip and close coil for power breakers
RE: Trip and close coil for power breakers
Once charged the spring would close the breaker and then open the breaker. One basic breaker had a close button and a mechanical current trip. No remote control at all.
Closing coils, tripping coils, and charging motors were options that most other plants included.
I haven't seen a power circuit breaker that could be closed unless there was enough stored energy to trip it open.
I seem to remember one breaker with remote close and trip. Once closed the spring could be recharged manually (No motor charging option installed). It then had enough stored energy for a remote trip, a remote close and another remote trip.
Bill
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"Why not the best?"
Jimmy Carter
RE: Trip and close coil for power breakers
AC close can be used for a mains if you have a MCC with a drawout or line connected CPT.