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sandeepn
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Join Date: Feb 2011
Posts: 39

MCB

05/03/2011 3:15 AM

What is the difference between Ac & DC MCB's some one can help me......????
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electricalexpert65
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Posts: 2061
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#1

Re: mcb

05/03/2011 5:30 AM

In AC arc quenching is easier as there would be curent zero in every half wave. But, in DC as there is no current zero, arc quenchung is a bit tricky. But, there are some blow out coil type design in DC MCBs. I look forward to KVS Reply on this.
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kvsridhar
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#3
In reply to #1

Re: mcb

05/03/2011 10:32 AM

Thanks for the compliment EE65, but i must confess that the DC MCB came due to Photovoltaic application, so my knowledge of these is not deep.

You are quite right that DC breaking is much more difficult than AC, so some extra blow-out device is required. In a large contactor for example, a blowout coil can be used perhaps, but in a small device like the MCB, a permanent magnet suggests itself, especially the very powerful new NdFeB magnets. Here are a couple of images from an ABB patent using PM blowout....

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sandeepn
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#5
In reply to #1

Re: mcb

05/03/2011 11:56 PM

Thankyou EE6,am waiting for your further datas
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TonyS
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#2

Re: mcb

05/03/2011 7:58 AM

Physical size is the first thing you will notice, as EE65 points out the arc path is so much longer for DC.

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hithuanand
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India - Member - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Apr 2010
Location: Asia/India
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#4

Re: MCB

05/03/2011 12:11 PM

This is Havell's MCB (old model)
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