Electrical machine MCQ #7


1) The armature voltage control of dc motor will provide constant _____.
      (a) current drive
      (b) torque drive
      (c) voltage drive
      (d) none of this.

2) The field current control of DC shunt motor will provide constant ______.
      (a) current drive
      (b) torque drive
      (c) voltage drive
      (d) HP drive

3) The plugging gives the
      (a) Zero torque breaker
      (b) Smallest torque breaker
      (c) Highest torque breaker
      (d) None of them

4) Motor is a machine which converts
      (a) Electrical Energy into Mechanical Energy
      (b) Mechanical Energy into Electrical Energy
      (c) Both A&B   
      (d) None of these



ANSWER: | 1-b | 2-a | 3-c | 4-a |

5) Core Losses are
      (a) Eddy Current Loss 
      (b) Hysteresis loss
      (c) Both A&B   
      (d) None of these

6) Copper Losses are
      (a) Constant Losses   
      (b) I2R Losses
      (c) Both A&B   
      (d) None of these

7) Slip When Nr=Ns
      (a) 0   
      (b) 1
      (c) 0.5 
      (d) 0.4

8) What is the value of frequency when Ns=1000 RPM, P=6
      (a) 30Hz
      (b) 50Hz
      (c) 40Hz
      (d) 60Hz



ANSWER: | 5-c | 6-b | 7-a | 8-b |

9) External Resistance is observed in
      (a) Slip Ring Induction Motor
      (b) Squirrel Cage Induction Motor
      (c) Both A&B   
      (d) None of these

10) The synchronous motor can be made self-starting by providing.
      (a) Damper winding on rotor poles
      (b) Damper winding on stator
      (c) (a) or (b)
      (d) None of the above

11) Which of the following motors have almost constant speed over their full load range?
      (a) DC series motors
      (b) DC shunt motors
      (c) Low resistance squirrel cage motors
      (d) (b) and (c) both

12) Which of the following motor one will choose to drive the rotary compressor?
      (a) Universal motor
      (b) D.C. series motor
      (c) Synchronous Motor
      (d) D.C. shunt motor



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