Online Quiz Questions on DC Motors - Set 03 - ObjectiveBooks

Online Quiz Questions on DC Motors - Set 03

Practice Test: Question Set - 03

1. If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will
    (A) Increase
    (B) Decrease
    (C) Remain same
    (D) Become zero

2. Torque developed by a D.C. motor depends upon
    (A) Magnetic field
    (B) Active length of the conductor
    (C) Current flow through the conductors
    (D) All above factors

3. D.C. generators are installed near the load centers to reduce
    (A) Iron losses
    (B) Line losses
    (C) Sparking
    (D) Corona losses

4. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control
    (A) Drum type controller is used
    (B) Three point starter is used
    (C) Four point starter is used
    (D) All above can be used

5. If the supply voltage for a D.C. motor is increased, which of the following will decrease?
    (A) Starting torque
    (B) Operating speed
    (C) Full-load current
    (D) All of the above

6. No-load speed of which of the following motor will be highest?
    (A) Shunt motor
    (B) Series motor
    (C) Cumulative compound motor
    (D) Differentiate compound motor

7. For starting a D.C. motor a starter is required because
    (A) It limits the speed of the motor
    (B) It limits the starting current to a safe value
    (C) It starts the motor
    (D) None of the above

8. In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be
    (A) Almost negligible
    (B) Rated full-load current
    (C) Less than full-load current
    (D) More than full-load current

9. The starting resistance of a D.C. motor is generally
    (A) Low
    (B) Around 500 Q
    (C) 1000 Q
    (D) Infinitely large

10. The condition for maximum power in case of D.C. motor is
    (A) Back e.m.f. = 2 × supply voltage
    (B) Back e.m.f. = I × supply voltage
    (C) Supply voltage =I × back e.m.f.
    (D) Supply voltage = back e.m.f.

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