[crims0n]

When I was a kid I always wondered why Dr. Sattler had to manually prime/charge the breaker before enabling it. Apparently it is because that model (and others like it) use a spring to quickly close the circuit. When she is priming it puts tension into the spring, and when she presses the button it quickly releases and completes the circuit. This is done to prevent arc flashes due to the high voltage and amperage, since the coiled spring snapping into place can complete the circuit much faster than any human pulling a lever could.

[ErroneousBosh]

We have ones like that at work for doing generator switchover - talking about Aggreko 20-foot shipping container generators providing hundreds of kW to power a pair of UPSes the size of a full-size Ford Transit, not your cute little 130-from-Hofer-pull-the-string-puttputtputt genny ;-)

You pump up the handle to charge a pneumatic cylinder and when you cut over it throws a set of three contacts about the size of a first-gen Kindle from one side to the other, switching from incoming mains to genny power in about 1/100th of a second.

It goes with a hell of a bang.

[sandyarmstrong]

> it puts tension into the spring

Well it certainly put tension into the scene! Thanks.