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Westinghouse Seltronic MCCBs - Settings and Time-Current curves

Westinghouse Seltronic MCCBs - Settings and Time-Current curves

Westinghouse Seltronic MCCBs - Settings and Time-Current curves

(OP)
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 ?

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

EasyPower has curves for these in its library.

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

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

(OP)
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 ?

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

What program are you using?

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

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

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.  

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

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.

RE: Westinghouse Seltronic MCCBs - Settings and Time-Current curves

(OP)
Thanks for your help. I've found the curve for the AB DE-ION breaker type NC in the www.eatonelectrical/unsecure/cms1 website, also in the SKM PowerTools library.

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