a) For running different machine tools where several speeds are required
b) For running paper machine requiring exact speed control
c) For running electric vehicles
d) For running rolling mills needing exact speed control

Ans: (a)

a) Copper losses in the stator
b) Friction and winding losses
c) Sum of (a) and (b) above
d) Total losses in the rotor on no load

Ans: (d)

a) The frequency of rotor currents
b) The frequency of stator currents
c) Difference of the frequencies of the stator and rotor currents
d) Sum of the frequencies of the stator and rotor currents

Ans: (a)

a) Single-phase ac supply
b) Three- phase ac supply
c) Dc supply
d) Supply obtained from an inverter

Ans: (c)

a) Increases
b) Decreases
c) Remains constant
d) Increases and then becomes constant

Ans: (b)

a) Increases and its frequency decreases
b) Increases and its frequency increases
c) Decreases and its frequency increases
d) Decreases and its frequency decreases

Ans: (a)

a) Slip ring induction motor
b) Squirrel cage induction motor
c) Salient pole synchronous motor
d) Wound rotor synchronous motor

Ans: (a)

a) Run at dangerously high speed
b) Stop
c) Continue to run depending on load
d) None of these

Ans: (c)

a) That the motor stops
b) Current decreases slightly
c) Speed reduces slightly
d) Motor heats up with passage of time

Ans: (d)

a) Single excited machine
b) Double excited machine
c) Machine in which three-phase supply is fed to both stator and rotor winding
d) None of these

Ans: (c)

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