ELECTRICAL MACHINES QUIZ

Cross magnetization effects which of the following?

commutation

reduces the terminal voltage

reduction in main field flux

both 2 and 3

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Quadrature axis synchronous reactance is the ratio of

Vmin to Imin.

Vmin to Imax.

Vmax to Imin.

Vmax to Imax.

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For a DC Motor for constant load torque, what will happen to the armature current if armature resistance increases?

Increases.

Remain unchanged

Decreases.

None of above.

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Which of the following motor is more expensive for same KW output rating ?

Synchronous motor.

AC single phase motor.

DC Shunt Motor

Induction motor.

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Transformer oil is used as

both A and B.

an insulator.

inert medium.

a coolant.

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The slot edges in a DC machine are made of

Mild steel.

Silicon steel.

Fibre.

Cast iron.

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In shaded pole induction motors, the flux moves from ------------- region to ----------------- region respectively?

shaded, shaded

shaded, unshaded

unshaded, shaded

unshaded, unshaded

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A 220 V DC generator is run at full speed without any excitation. The open circuit voltage will be

220 V.

about 50 V.

about 2 V.

zero.

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To get the speed of DC motor is more than normal without wastage of electrical energy _____________ is used.

Rheostatic control.

None of above.

Ward Leonard control.

Any of above method.

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The no load and full load speed of DC motor are 1400 rpm and 1200 rpm respectively. What is the percentage speed regulation of the motor ?

18.25%.

15.30%.

16.67%.

14.28%.

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YOUR ANSWER : ?

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