Breakers Charged/Discharged

[itsmoked]

I got a tour of the local 'award winning' sewer plant. Danged impressive really.. They co-gen, burning digester gas to power the facility and heat the digesters to 98F plus all the buildings from the generator waste heat.

We walked thru a switch room that had several control centers racked with 480VAC breakers. They all had a raised protected RED button and a flush green button. They all had two little windows. One said; "CLOSED" or "OPEN" and the other window said; "Charged" or "Discharged". There was a complete mixture of the various cases. I presume the charged and discharged was referring to some sort of activation energy or operational readiness. I could see no obvious way to "pump up" or charge the units.

It also seemed strange to see a closed breaker stating: "discharged".

The only thing I can think of that fits the situation is that the "charged" state only has to do with closing the breaker, and so, can be safely in a "discharged" state all the time.
Have I got it right?

How would you charge these? Oh - they were about 6" inches wide by maybe 8" tall.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[sibeen]

Schneider (merlin gering or sqare D) breakers?

 

[rasevskii]

Charged and discharged usually refer to the springs that operate the breaker. This so that a maintenance man wont get hurt if during removal/racking out of the breaker there is no mechanical energy storage inside the breaker. Usually the springs are recharged automatically by the spring charging motor after each closure of the breaker. Strange is that you had a closed breaker but disharged springs.

Unless this is some newfangled design that doesnt use springs..

rasevskii

 

[itsmoked]

Sibeen I don't recall, but if I had to guess I'd say Square D due to the color scheme.

rasevskii; Are you saying the breaker has to be charged to trip?!

Keith Cress
kcress -

http://www.flaminsystems.com

 

[davidbeach]

Some breakers use one spring for both opening and closing, while others have separate closing and opening springs.

In the one spring design, it won't close unless there's enough charge on the spring for a close-open cycle. With these you'll often hear the charging motor after a close and the full charge on the spring is to do an open-close-open cycle.

In the two spring design, the motor charges the close spring and the act of closing the breaker chargers the opening spring. The closing spring is the recharged after each open. The closing spring can the be in the discharged state with the breaker closed. The breaker can't be racked out without being open (either mechanically interlocked or the racking operation will force a trip) so the opening spring will discharge at that point.

 

[waross]

Old school. We had breakers that were closed by a stored energy spring. There was a handle on the front which was "pumped" to charge the spring. Then the breaker could be closed either by the button on the front or remotely. A second spring which was charged by the closing of the breaker was used for opening. Opening could be by the button on the front or remotely. Once the breaker was closed, the spring was discharged, but could be charged and left ready for one more close operation. As was stated by others, there was a mechanical trip which discharged the spring when the breaker was withdrawn.
We had one of these used as a starter for a synchronous motor. Once the motor was started the rheostat was used to set the field current to a felt pen mark on the ammeter face. We would return in 20 to 30 minutes to readjust the field current to account for the field windings heating up and changing resistance. We would also pump up the spring, ready for the next mornings operation.
So you could have the breaker
Open and discharged,
Open and charged,
Closed and discharged, and
Closed and charged ready for an open-close cycle.
If the there was an attempt to close the breaker while it was receiving an open command, the spring would discharge without closing the breaker.
Even then a charging motor was an option. We didn't have one.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Cool! Thanks for the nice enlightenment folks. I can now rest, assured that if it said "uncharged" but was closed then that would not be preventing it from opening in a protective action.

Keith Cress
kcress -

http://www.flaminsystems.com