Speed Control in Three Phase Induction Motor - MCQs with Answers

Speed Control in Three Phase Induction Motor - MCQs with Answers

Q1. The method which can be used for the speed control of induction motor from stator side is

a. V / f control
b. Controlling number of stator poles to control N_s
c. Adding rheostats in stator circuit
d. All of these

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Q2. The consequent pole method used for controlling the number of poles can be used for

a. Only squirrel cage type motors
b. Only slip ring induction motor
c. For both squirrel cage and slip ring induction motor
d. None of these

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Q3. The best suited method for smooth speed control by controlling number of poles is

a. Consequent poles method
b. Multiple stator winding method
c. Pole amplitude modulation method
d. None of these

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Q4. In pole amplitude modulation method for controlling number of poles, practically, the wave used for modulation is

a. Square wave
b. Triangular wave
c. Saw tooth wave
d. Sinusoidal wave

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Q5. In cumulatively cascade method for speed controlling, if P_A is the number of poles of main motor and P_B is the number of poles of auxiliary method. Then the speed of the rotor B is given by

a. 120f / P_A + P_B
b. 120f / P_A - P_B
c. 120f / P_A
d. 120f / P_B

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Q6. In cascade control method, the set cannot be operated if

a. P_A > P_B
b. P_A < P_B
c. P_A = P_B
d. None of these

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Q7. Kramer system for controlling the speed of 3 phase induction motor is mostly used for motors of

a. Above 4000 kW
b. Below 4000 kW
c. Below 3000 kW
d. None of these

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Q8. The disadvantages of scherbius system used for speed controlling in 3 phase induction motor is

a. It cannot be used for slip ring induction motors
b. It cannot be used for squirrel cage induction motors
c. It can be used for large induction motors
d. None of these

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