Shunt Trip

[iwire]

Larry, I think you had a fluke, shunt trip breakers can handle maintained input.


Get over it. :grin:


Heres a challenge, someone find a make and model shunt trip breaker that will not handle maintained input.

 

[brian john]

Larry, I think you had a fluke, shunt trip breakers can handle maintained input.


Get over it. :grin:


Heres a challenge, someone find a make and model shunt trip breaker that will not handle maintained input.

Many shunt trips have clearing contacts that remove power after operation. This allows the manufactures to make smaller high energy units. If the contacts are welded or closed for any reason it is not uncommon for the shunt to fry.

 

[iwire]

Many shunt trips have clearing contacts that remove power after operation. This allows the manufactures to make smaller high energy units. If the contacts are welded or closed for any reason it is not uncommon for the shunt to fry.

I agree, but thats a failure of the contacts, not a lack of clearing contacts.

The same can be said of mechanically held lighting contactors.

 

[LarryFine]

Larry, I think you had a fluke, shunt trip breakers can handle maintained input.


Get over it. :grin:


Heres a challenge, someone find a make and model shunt trip breaker that will not handle maintained input.

Not always, I am, and I did.


The breaker is a Siemens QJ23B225 with an S01QJOR3 accessory contact, whose label says, in part:

1. Caution: auxiliary switch must be connected in series with the shunt trip. Customer to connect leads "A & T" as shown in diagrams.

2. Customer to connect leads "S & C" to applicable power source.

Note that A and C are the NC contact leads, and S and T are the trip-coil leads.

There's also a little chart that shows tripping current at .033 seconds of .31a at 120v, .54a at 208v, .57a at 220v, and .62a at 240v.