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.Management Sciences
Category: Industrial Drives
The starting torque of a D.C. motor is independent of which of the following?
A. Flux
B. Armature current
C. Flux and armature current
D. Speed
Which of the following machines has heavy fluctuation of load ?
A. Printing machine
B. Punching machine
C. Planer
D. Lathe
need frequent starting and stopping of electric motors ?
A. Paper mills
B. Grinding mills
C. Air-conditioners
D. Lifts and hoists
Which of the following motors is usually preferred for kiln drives ?
A. Cascade controlled A.C. motor
B. Slip ring induction motor
C. Three phase shunt wound com-mutator motor
D. Any of the above
_______________has the least value of starting torque to full load torque ratio?
A. D.C. shunt motor
B. D.C. series motor
C. Squirrel cage induction motor
D. Slip ring induction motor
For which of the following applications motor has to start with high acceleration ?
A. Oil expeller
B. Floor mill
C. Lifts and hoists
D. Centrifugal pump
Belted slip ring induction motor is almost invariably used for_________________?
A. water pumps
B. jaw crushers
C. centrifugal blowers
D. none of the above
__________________ 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
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