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bonala123
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Join Date: Sep 2009
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Voltage Relays and Current Specs

10/14/2009 9:02 AM

For IDMT and DT relays how important is pickup / drop out current ratio. Also the same for voltage relays.

Are there any specification as per standards such as IEC, ANSI etc.
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Matt Skywalker
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#1

Re: Current and voltage relays

10/14/2009 10:42 AM

Yes the ratio is important since it's an inverse relay, the trip time goes decreases when fault current increases.

Check ANSI 51.

There's a number of web sites with examples of IDMT and DT uses in the same application. Do your search on "IDMT ANSI 51" and check out the Engineering Tips hits.

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maveric_manic
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#2

Re: Voltage Relays and Current Specs

10/15/2009 3:34 AM

A lot of times the relay in question specification will tell you the min/max voltage for activating the relay and working voltage of the contacts.

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