Westinghouse Seltronic MCCBs - Settings and Time-Current curves

[EddyWirbelstrom]

I'm doing protecton grading in a 415V distribution system which includes old Westinghouse Seltronic NC molded case circuit-breakers. My websearch for Seltronic data was unsuccessful.
Can anyone supply LTD, STD, Inst protection setting ranges, tolerances, and time-current curves ?

 

[dpc]

EasyPower has curves for these in its library.

You can probably get the information from Cutler-Hammer (Eaton Electrical) - they still sell these.

 

[EddyWirbelstrom]

Could you define the setting range for LTPU, LTTD, STPU, STTD, and Inst.
A few time-current co-ordinates would define the curves.

Is EasyPower a software for system analysis including protective device co-ordination curves ?

 

[rbulsara]

What program are you using?

SKM has that in their library. Contacting Eaton-Cutler Hammer is you best bet.

 

[dpc]

This is very rudimentary solid-state trip. Only a long-time thermal portion which is non-adjustable and an instantaneous trip (which they call "short-time").

Long-time pickup is function of the rating plug. The long-time curve looks pretty much a typical thermal curve on a thermal-mag breaker.

Instantaneous (short-time) is adjustable from 4X to 8X with an override pickup that is a function of the rating plug size.

The maximum interrupting time for the instantaneous is about 0.033 seconds.

Hope that helps.

 

[davidbeach]

I don't have time right now to find it again, but I have found these on the Eaton/Cutler-Hammer website. They include a lot of obsolete Westinghouse curves once you find the right place.

 

[davidbeach]

http://www.eatonelectrical.com/unsecure/cms1/AD29168.PDF

 

[EddyWirbelstrom]

Thanks for your help. I've found the curve for the AB DE-ION breaker type NC in the

http://www.eatonelectrical/unsecure/cms1

website, also in the SKM PowerTools library.