What are those disc things all around the room. In fact, what is that room?
@Julie. And, errr, I have made a solemn promise to myself to not operate an air circuit breaker anytime soon!
P.S. And why must the OB3 NOT BE OPERATED? Is/was it defective like the above? All very interesting by the way.
The red Yellow and blue busbars are the three phases we connected the equipment to, we could choose the voltage on those from 200V to 38kV depending upon the test requirements, the disks are insulators.
That is a test bay at a switchgear testing station, low - medium voltage, unfortunately I don't have photos of the other bays some of which go to high voltage (66kV+)
The OB3 operates like many of the era and is known as "dependant manual"
This means the speed of contact closure is completely dependent upon the operator, if you are hesitant and do it slowly or even stop and reverse, then the contacts will not make properly.
Switchgear is generally designed to close onto a fault, but opening a fault is not always required (switches), and when it is able to interrupt a fault (breaker), they sometimes use different contacts, and in any case they always need to follow the proper cycle from: contact made, contact separation, arc, arc control, then arc extinction then fully open.
Dependant manual interrupts this cycle.
As long as you make a swift closure, even on to a fault, the breaking cycle can complete safely.
As you may guess I worked at both a switchgear manufacturer and testing station , unfortunately I had to go out and investigate some incidents including a number where deaths had been involved.
I did attend one where an operator had started to close a switch (~11kV) designed in the late '40s manufactured in the 50s - so dependant manual, and realised he hadn't removed the earth links, so hesitated half way through and tried to open it.
5 out of the 6 people in the switchroom died, the one who lived was near the door managed to get out but was engulfed in the burning oil, it was horrific to be honest, one of the worst I investigated.