# An 8 pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in

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An 8 pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in the opposite direction of revolving magnetic field. The frequency of the rotor current is (a) 30 Hz (b) 60 Hz (c) 120 Hz (d) 180 Hz

by

30 Hz

As the frequency of the rotor is given by
F= N*P/120
so from the above equation the frequency of the rotor current can be easily calculated
i.e. 1800×8/120=30
Hence the required value of rotor frequency is 30 Hz

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