Related Questions

It is advisable to avoid line starting of induction motor and use starter because
A It will run in reverse direction
B It will pick up very high speed and may go out of step
C Motor takes five to seven times its full load current
D Starting torque is very high
Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A Low cost
B Wide speed range
C Stability
D High starting torque
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
A pony motor is used for the starting which of the following motors?
A Squirrel cage induction motor
B Schrage motor
C Synchronous motor
D None of the above
In squirrel cage induction motors which of the following methods of starting cannot be used?
A Resistance in rotor circuit
B Resistance in stator circuit
C Autotransformer starting
D Star-delta starting
When the primary direct crank of a reciprocating engine makes an angle of $$\theta $$ with the line of stroke, then the secondary direct crank will make an angle of _________ with the line of stroke.
A $$\frac{\theta }{2}$$
B $$\theta $$
C $$2\theta $$
D $$4\theta $$
________ 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 non-self starting ?
A D.C. series motor
B synchronous motor
C Squirrel cage induction motor
D Wound round induction motor
Synchronous motors are generally not self-starting because
A the direction of rotation is not fixed
B the direction of instantaneous torque reverses after half cycle
C startes cannot be used on these machines
D starting winding is not provided on the machines
Star-delta starting of motors is not possible in case of
A Single phase motors
B Variable speed motors
C Low horse power motors
D High speed motors

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