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fuse and overload

fuse and overload

fuse and overload

(OP)
sorry if this is posted, I'm sure it probly is, but didn't find anything...
I've inherited a bunch of drawings of which part are motor control cktry...typical input power-motor contactor-overload however, they all have fuses on all 3 phase wires before the contactor/overload.  I knwo NEC says each phase wire must be fused, but is that in addition to the overload?  Why?

RE: fuse and overload

Fuses are for short-circuit protection. Overload is for thermal protection - like what you have when lifting a too heavy load or pumping too much water.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: fuse and overload

In short....fuses protect the mains supply and your overloads protect the motor!!

              Jeff
         www.motors-direct.co.uk

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