scottam99
Member
- Location
- Vero Beach Florida
The breaker that feeds the elevator is not a shunt trip breaker. Is there any reason we can't use a contactor and coil for that would become the shunt?
A contactor instead if shunt trip breaker for elevator
- Thread starter scottam99
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gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
I can't see why not, just make sure you set it up as fail open, or whatever the AHJ says it needs to be.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
You cannot use a contactor as a disconnecting means, if that is what you are asking.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
This is likely the elevator shut down in the event that you're about to get sprinkler activation in the machine room or elevator hoistway.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
It would appear to me that you are allowed to use the disconnecting means to shut off power if the sprinklers go off but are not required to do so.
So I would say probably the contactor idea is OK.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
It occurred to me to clarify, in light of what you posted, if you use a contactor you have to make sure there is a manual reset mechanism. You don't want the elevator re-energized as soon as the fire alarm panel is reset.
This.is all backwards.
A breaker is energize to open (and close with the larger ones). In the “off state” it stays that way. It is designed to operate only occasionally. It has large contact tips and arc chutes to allow very high trip currents.
A contactor is normally spring return and must be energized continuously to close. There are latching contactors that operate like a breaker but for the size you are probably looking at, why would you bother? Second it is designed for a lot of operations with extra thick (not large) contact tips but not much in the way of interrupting ratings...that’s the breakers job.
In 4160 equipment though we often have the “transformer feeder”. This has a fused non-load break disconnect with a contactor often rigged to open and close from the disconnect with early break/late make auxiliary contacts. The contactor acts like your idea and can be interlocked (“shunt trip”) although the relay used to do this has to be latching. Sounds like a Frankenstein? Yep...just buy the breaker. They are too cheap to do this stuff.
A breaker is energize to open (and close with the larger ones). In the “off state” it stays that way. It is designed to operate only occasionally. It has large contact tips and arc chutes to allow very high trip currents.
A contactor is normally spring return and must be energized continuously to close. There are latching contactors that operate like a breaker but for the size you are probably looking at, why would you bother? Second it is designed for a lot of operations with extra thick (not large) contact tips but not much in the way of interrupting ratings...that’s the breakers job.
In 4160 equipment though we often have the “transformer feeder”. This has a fused non-load break disconnect with a contactor often rigged to open and close from the disconnect with early break/late make auxiliary contacts. The contactor acts like your idea and can be interlocked (“shunt trip”) although the relay used to do this has to be latching. Sounds like a Frankenstein? Yep...just buy the breaker. They are too cheap to do this stuff.
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