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Need Help Finding a Westinghouse CO relay Curve (1271071-A)
2

Need Help Finding a Westinghouse CO relay Curve (1271071-A)

Need Help Finding a Westinghouse CO relay Curve (1271071-A)

(OP)
Hello all,

Anyone have a TCC curve for the Westinghouse CO relay in the picture? The model number we have been given is 1271071-A. It appears to be an 'old' relay. Thanks.

Any information will be helpful if you have even seen this one before.  

RE: Need Help Finding a Westinghouse CO relay Curve (1271071-A)

Difficult to say for sure.  Before they started with model numbers such as CO-9, CO-11, etc to indicate curve shape, there was the CO.  But for a while it had options for definite time, inverse time, and very inverse.  The very old CO relays had spring tension adjustments.  And there have been a lot of special orders of CO relays over the years.  

I'd suggest putting it on a test bench and doing a calibration test to see what the curve looks like.

You could try contacting ABB US - they bought this part of Westinghouse.  You can still buy brand new CO relays if you're so inclined.   

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

RE: Need Help Finding a Westinghouse CO relay Curve (1271071-A)

Hi eleceng01:
Try this website:
www.electricalmanuals.net
They have some old equipment manuals on this site, there are no CO type relays listed under Westinghouse, but most of them are listed under ABB.

Good Luck.
Ang

RE: Need Help Finding a Westinghouse CO relay Curve (1271071-A)

You're correct in stating that it is an old relay.  I have a cross reference sheet that lists the old serial numbers and the approximate equivalent using the new numbering scheme.  Your relay has a definite time curve similar to a CO-6 relay (serial no. 1875244).  The relay serial numbers can be used to identify the original setting ranges and curve shapes.  Your relay has a tap range of 4-15 amps and no instantaneous trip function.  The equivalent CO-6 relay has a 4-12 amp tap range and no instantaneous trip.  Hope this helps.

RE: Need Help Finding a Westinghouse CO relay Curve (1271071-A)

(OP)
croudk,

Thanks. Very useful info. We had 'eye-balled' the CO relay from a previous study report (1963) & guessed that it was a CO-6.

Any chance of sharing that reference sheet?  

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