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.Management Sciences
Category: Industrial Drives
__________________ has relatively wider range of speed control?
A. Synchronous motor
B. Ship ring induction motor
C. Squirrel cage induction motor
D. D.C. shunt motor
Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?
A. D.C. motor
B. Squirrel cage induction motor
C. Wound rotor induction motor
D. Synchronous motor
For a D.C. shunt motor which of the following is incorrect ?
A. Unsuitable for heavy duty starting
B. Torque varies as armature current
C. Torque-armature current is a straight line
D. Torque is zero for zero armature current
For a particular application the type of electric-and control gear are determined by which of the following considerations ?
A. Starting torque
B. Conditions of environment
C. Limitation on starting current
D. Speed control range and its nature
E. All of the above
Which part of a motor needs maximum attention for maintenance ?
A. Frame
B. Rearing
C. Stator winding
D. Rotor winding
_________________method of starting a three phase induction motor needs six terminals ?
A. Star-delta
B. Resistance starting
C. Auto-transformer
D. None of the above
The cost of an induction motor will increase as________________?
A. horsepower rating increases but r.p.m. decreases
B. horsepower rating decreases but r.p.m. increases
C. horsepower rating and operating speed increases
D. horsepower rating and operating speed decreases
A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is____________________?
A. slop speed operation
B. high starting torque
C. low windage losses
D. all of the above
In ________________ method of staging three phase induction motors the starting voltage is not reduced?
A. auto-transformer
B. star-delta
C. slip ring
D. any of the above
Which of the following happens when star-delta starter is used ?
A. Starting voltage is reduced
B. Starting current is reduced
C. Both A. and B.
D. None of the above
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