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High voltage switchgear usually applies interrupting arc quenching chambers to extinguish the arc between two contacts. a) Which principles are applied to extinguish the arc? b) Explain the extinction of the arc by an arc quenching chamber. Make some drawings to support your explanation. c) Which materials are normally used for the contacts? Which gas is used? Why?

2007-09-13 09:52:54 · 3 answers · asked by meesogynist 1 in Science & Mathematics Engineering

3 answers

You need to do your own homework. However here are a few items to get you started:

The three most common interrupting mediums are:

- Oil
- SF6
- Vacuum

Tungsten carbide use to be very common for interrupter contacts. Modern interrupter contacts are generally a high-tech concoction of metals.

2007-09-13 12:46:56 · answer #1 · answered by Thomas C 6 · 2 0

http://www.energymanagertraining.com/equipment_all/electrical_system/MinimumOilcircuitbreaker.htm.....
here is a good cross section of an oil circuit breaker...
In an OCB the idea is pretty simple the arc is quenched by an oil dielectric..Are you over 40 then there was a product that scared half the US into a panic call Askeral it was an oil that was a PCB polychloranatedbiphenyl. Any way it caused cancer and a lot of people think now that all oil in all transformers is Ask. Its not....The there is the Gas Insulated X-former its a metal encased transformer that uses the gas SF6 (sulfur -fluorine) for the insulation ...this greenhouse gas is replaced when it gets low and is generally produced by a petroleum refinery...Check out the drawing on the link i sent its not like this on all larger systems but you can get these from about 12kv to perhaps 500kv...they have a lot to be said for them but what comes to mind from me is EXPENSIVE...So there ya go..a few Pics and a few answers...From the E.....

well i went to the link I sent and they had moved it in the last ten minutes or so...go figure that..well try this one..also let me add that the newer oil is an Ester oil much like that found in the A/C system in your car.....

http://www.doble.com/content/news/Tools%20Diagnose%20the%20Condition%20of%20Oil%20Circuit%20Breakers_T&D%20World%20November%202003.pdf

if this does not work i will get you a decent pic...sooner or later...:) E...

2007-09-13 11:28:07 · answer #2 · answered by Edesigner 6 · 0 0

a=circuit breaker consist of fixed and moving contacts which are touching each other under normal conditions, when circuit breaker is closed.Whenever a fault occures,the trip coils get energized. The moving contacts are pulled by some mechanism and therefor the circuit breaker is opened and the circuit is broken, When the breaker opens an arc is formed in an arcing chamber that it is quenched by a gas released by the heat of the arc .there are various type of circuit breaker:

like , Minim om oil,SF6 and Air blast to extinguish arc that is formed in chamber in time of opening circuit breaker.
The SF6 is used as dielectric and arc interrupting. it is featured by compression of the SF6 required to blow the arc right at the tripping instant by the action of the moving contact
The performance of CB. are mainly depend on SF6 gas density(not on sf6 gas pressure) .Fixed and moving contact's

surface are silver coated .

2007-09-13 13:42:13 · answer #3 · answered by koh_arian 2 · 0 0

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