Electrically operated medium voltage circuit breaker operation 1

[bdn2004]

If a medium voltage circuit breaker is equipped with a spring charging motor does that mean that it is electrically operated?

 

[jghrist]

Yes, but then I don't know of any non-electrically operated medium voltage circuit breakers.

 

[ScottyUK]

Well, most of them can be manually charged and manually closed and tripped, but it's hardly the kind of practice any sane person would routinely undertake. Far too much chance of being up close & personal when it goes wrong.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[jraef]

I think all "electrically operated" circuit breakers are just that, a spring charging mechanism and an electrically operable open/close command circuit. The issue is you cannot slowly close it, there has to be a snap-action, hence the spring charge. You can manually charge it and manually push the button to open or close it, however I don't know if anyone still sells a manual-only version though. Wouldn't be a big seller in my mind, especially in the modern age of Arc Flash safety awareness.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[LionelHutz]

The breaker would also need a closing coil and a trip coil to be considered electrically operated. The charging motor just charges the closing springs. It does not open or close the breaker.

 

[Zogzog]

Never seen a breaker with a charging motor but without close/trip coils.

 

[WTRVS]

Some Ormazabal breakers have to be charged by pulling the switching lever counter clockwise first. This action is needed to charge the springs and allow it to open in case of a trip.

Then the breaker can be closed by turning the switching lever clockwise and counter clockwise to open.

On those breakers, a charging motor can be installed as an option but it will also work without. Ofcourse motor operated is more practical and more safe.

 

[jraef]

Well, I stand corrected then. It appears they are still selling a manually cranked MV circuit breaker. Never heard of them here in North America, maybe that's why.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[jghrist]

Even if the springs are manually charged, tripping would be electrical for the normal function of a circuit breaker, that is breaking a circuit to clear a fault. If only manual opening is required, you would use a switch, not a circuit breaker.

 

[7anoter4]

The spring actuator-charged by solenoid or motor for closing-and free spring disconnected is in trend to be substituted by
permanent magnet actuator as in following link:

http://www.google.co.il/url?sa=t&rc...ion&source=web&cd=4&ved=0CEEQFjAD&url=http://

http://www05.abb.com/global/scot/sc...zvmiCA&usg=AFQjCNFOgz8AFuH4ZebrLzPxmcfs2FDcEw

 

[PHovnanian]

If you descent far enough down the LV breaker family tree, you'll find shunt-trip breakers. These are manually charged, but can be tripped electrically. I don't know if this makes them 'electrically operated' by the commonly accepted definition.