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S. Murali
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Join Date: Jul 2008
Posts: 4

ac dc ampere rating

07/31/2008 3:48 AM

contactor contact ampere rating for ac current and dc current is same or is there any derating to be considedrte while using in dc
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Anonymous Poster
#1

Re: ac dc ampere rating

07/31/2008 4:40 AM

http://cr4.globalspec.com/thread/24691/acand-dc-ampere-rating-in-the-contact
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jmart23
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Join Date: Jun 2006
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#2

Re: ac dc ampere rating

08/01/2008 7:35 AM

Yes!
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Emjay4119
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Join Date: Dec 2005
Location: Queensland Coalfields Australia.
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#3

Re: ac dc ampere rating

08/28/2008 10:21 PM

AC contactors are not compatible with switching duty for DC at any meaningful current ratings. AC contactors rely on zero crossing to extinguish the arc wheras with DC it must be blown out. Blowout coils are routinely fitted in series with the contact and the magnetic field so created is directed to either side of the arc chute via the core and wings. The magnetic field forces the arc (which is a conductor) up into the arc chute elements where it becomes segmented and finally extinguished. Heavy DC currents are always interrupted with a bang, DC just wants to keep on flowing especially in inductive circuits.
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