Breakers Charged/Discharged
Breakers Charged/Discharged
(OP)
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.
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






RE: Breakers Charged/Discharged
RE: Breakers Charged/Discharged
Unless this is some newfangled design that doesnt use springs..
rasevskii
RE: Breakers Charged/Discharged
rasevskii; Are you saying the breaker has to be charged to trip?!
Keith Cress
kcress - http://www.flaminsystems.com
RE: Breakers Charged/Discharged
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.
RE: Breakers Charged/Discharged
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
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"Why not the best?"
Jimmy Carter
RE: Breakers Charged/Discharged
Keith Cress
kcress - http://www.flaminsystems.com