Reluctance motor can produce torque at ________(a) any speed less than synchronous speed(b) synchronous speed only(c) any speed greater than synchronous speed(d) all of the mentionedI have been asked this question in a job interview.My question is based upon Reluctance Motor topic in section Basic Concepts in Rotating Machines of Electrical Machines

Reluctance motor can produce torque at ________(a) any speed less than

1.	Reluctance motor can produce torque at ________(a) any speed less than synchronous speed(b) synchronous speed only(c) any speed greater than synchronous speed(d) all of the mentionedI have been asked this question in a job interview.My question is based upon Reluctance Motor topic in section Basic Concepts in Rotating Machines of Electrical Machines
Answer» Correct choice is (b) synchronous speed only Easiest explanation: Te(av) = -1/4 ∅max^2(Rlq – RLD)(1/2 sin⁡(-2δ)), w = synchronous speed if wr≠w then Te(av)=0, andif wr=w then Te(av)≠0, as the LAST TERM in the EQUATION 1/2 sin⁡(-2δ) does not vary with time, andhence average torque is not EQUAL to zero.

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