ELECTRICAL MACHINE MCQ_55(DC MOTOR_07)


Q.91 The torque- current characteristic of a dc series motor is initially ____ and finally becomes ___when the load current becomes large.
    A. hyperbola; linear
    B. parabola; non linear
    C. parabola; linear
    D. hyperbola; non linear
Ans.: C

Q.92 The Torque-current characteristic of dc series motor
    A. changes steps from one curve to another
    B. changes smoothly from one curve to another
    C. changes exponentially from one curve to another
    D. any of the above depend upon load
Ans.: B

Q.93 The characteristic relating the useful torque to armature current is parallel to the ____, but is slightly __it.
    A. armature torque-speed; above
    B. Gross torque- armature current; above
    C. Gross torque- armature current; below
    D. Gross torque- load current; above
Ans.: C

Q.94 The speed- torque characteristic of a series motor can be derived from a
    A. speed – armature current characteristic
    B. torque-armature current characteristic
    C. torque-speed characteristic
    D. Both A and B
Ans.: D

Q.95 The dc series motor has
    A. high torque at high speed
    B. high torque at low speed
    C. low torque at low speed
    D. low torque at high speed
Ans.: B

Q.96 The speed of the dc series motor changes considerably with
    A. decreasing load
    B. increasing load
    C. does not depend on load
    D. none of the above
Ans.: B

Q.97 The dc series motor has
    A. high torque at high speed
    B. high torque at low speed
    C. low torque at low speed
    D. low torque at high speed
Ans.: D

Q.98 A dc series motor is very useful for
    A. traction purpose
    B. hoist and lifts
    C. where at low speeds a high starting torque is required to accelerate large masses
    D. all of the above
Ans.: D

Q.99 which one of the compound motor is generally used in practice?
    A. cumulative compound motor
    B. differential compound motor
    C. Both are equally used
    D. not defined
Ans.: A

A.100 which of the motor has a high starting torque together with a safe no load speed?
    A. shunt motor
    B. series motor
    C. compound motor
    D. long shunt motor
Ans.: C

Q.101 DC compound motor has a high starting torque together with a safe no load speed, due to this factors it make it suitable for use
    A. with heavy intermittent load
    B. with light load
    C. with light load throughout its operation
    D. all of the above
Ans.: A

Q.102 A motor which has nearly ____ is said to have good regulation.
    A. variable speed
    B. intermittent speed
    C. constant speed
    D. variable with intermittent
Ans.: C

Q.103 The armature resistance of a 200 V shunt motor is 0.4 ohm and no load current is 2A. Find approximately the no load speed when loaded and taking an armature current of 50A, the speed is 1200 rpm.
    A. 1250 rpm
    B. 1328 rpm
    C. 1420 rpm
    D. 1350 rpm
Ans.: B

Q.104 In dc shunt motor, if armature current increases
    A. back emf decrease
    B. speed decreases slightly
    C. Both A and B
    D. speed increases slightly
Ans.: C

Q.105 A dc shunt motors are suitable for
    A. constant speed and low starting torque
    B. constant speed and high starting torque
    C. constant speed and medium starting torque
    D. variable speed and medium starting torque
Ans.: C

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