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GEC CDG14 Overcurrent relay curves 2

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PERRO

Electrical
Jul 18, 2002
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Do you know where I can find the curves of a GEC CDG14 overcurrent relays, or where I can find the B.S. 142:1966 standar?
 
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an adder to my previous msg
acc to page 139 of PRAG ( where you can see the curves) the formula for the extremely inverse curve is t=80/(Isquare-1) where t is op time in sec and I is current (multiple of plug setting)
 
Be careful, the curves for the CDG do not follow a formula.

The formulas in the PRAG that you mention are for electronic/numerical relays.

If you look at the curve for the CDG14, at 5 times the current setting the relay operates in 2.05 seconds.

If you put the same value into the EI formula, the operating time is 3.33 seconds

If you don't have a copy of the PRAG, contact ALSTOM for a copy of the CDG14 publication.
 
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