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Wound Rotor Motor Fusing (Question of the Week)

Question asked by rcramereleceng on Sep 13, 2019

What is the correct fuse rating to provide short-circuit protection for a 100 HP, 200 V, 3 phase, wound rotor motor?

A. 200A

B. 250A

C. 300A

D. 110A 


This question is on a test for Residential Electrician Training.  None the less, my real world applications with Wound Rotor Motors has been existing - as opposed to Design.  My request is for anyone who has an example of where that original Design started in the NEC (including Annex D, Example D8) and if that Design worked upon Commissioning where if changes were made - what were they and why.