Question

In a synchronous machine, cylindrical pole construction has been found to suit best for ___________

(a) low speed prime movers

(b) high speed prime movers

(c) medium speed prime movers

(d) any of the mentioned

This question was posed to me in an interview for job.

The origin of the question is Constructional Features of Rotating Electrical Machines-3 in section Constructional Features of Rotating Electrical Machines of Electrical Machines

Answer 1

Right option is (b) high speed prime movers

Best explanation: For high speed prime movers, if salient pole construction is used, the rotor structure may not be able to withstand the enormous centrifugal forces, developed by the salient poles. Therefore, cylindrical rotor construction is best suited from mechanical considerations.