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

[Eleceng01]

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.

 

[dpc]

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

 

[ANGIBEW25]

Hi eleceng01:
Try this website:

http://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

 

[croudk]

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.

 

[Eleceng01]

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?