Arc Dividers and Extinguishers

In arc chutes the arc is splitted into no. of small arc lines and due to small area of these arc line it can be easily exinguished by any method e.g. by Hi Pressure compressed air,by SF6, By vaccum as per the type of the circuit breaker.

Hi Sir

Thanks for your information, Sir can you please tell me why arc chutes are made up of copper and how it is functioning in mcbs and contractors,where we don't use any compressed air or vaccum

In my experience, the deion plates are made of steel and are held between insulating plates. It won't do to have them electrically connected would it? Then the arc would not be split. In some good designs, the insulating plates have an "ablative" property, which means that they emit gases which help quench the arc when the arc heat hits them.

In MCBs which are low cost and high volume products, the design is mainly oriented towards automatic production. The cathode voltage drop is about 20V and therefore at least 12 of them are required to produce a drop of 240V, so you will generally see 13 plates in MCB arc chute. You may have seen some arc chute where the grids may have been copper plated, but with a very low cost target, one cannot afford to use copper in an MCB arc chute i think.

Does this help? please free to ask if you need more information.

HI Sir

Sir can u plz tell me more about cathode voltage drop and its working, and also about "ablative" metal. if u have some simple E notes on breakers plz send me.

Hi Jaykrish,

i give below an extract from Schneider Electric's Cahiers technique # 154. You will find a wealth of information in these marvellous publications from Schneider (formerly Merlin Gerin, Grenoble, France). Please visit this site and download whatever you are interested in ...

http://www.schneider-electric.com/sites/corporate/en/products-services/technical-publications/technical-publications.page

Good luck, and feel free to ask me anything i may know ...

regards,

sridhar

Hi sir

Thanks for this Schneider link, Many time i visit Schneider and telemecanique sites to get details abt their drives, servo motors and sepam but i never get this page, it contains lots of notes, thanks for introducing this page. May I send u personal mails, bcoz Ur answers r so easy to understand, can u plz give me ur id ?

Thanks for your kind words, here it is ... kvsridh@gmail.com. Please feel free to write to me anytime .. as i am retired, my time is my own !

Specific to Low Voltage circuit breakers, the "De-ion" grid invented by Dr Slepian of Westinghouse does the job of (a) splitting the arc into small segments so that the cathode drops in series exceeds the voltage required to sustain the arc and (b) cool and deionise the arc segments. Here is an extract from a textbook...

And these plates act as "quick-action" capacitors which get charged by the energy of the arc and so extinguishing it.