Related Questions

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
A This will make armature to take heavy current, possibly burning it
B This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
C Nothing will happen to motor
D Motor will come to stop
If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens
A Nothing will happen to the motor
B This will make armature to take heavy current, possibly burning it
C This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
D Motor will run at very slow speed
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because
A Back e.m.f. is equal to armature drop
B Armature drop is negligible
C Flux is proportional to armature current
D Flux is practically constant in D.C. shunt motors
In D.C. shunt motors as load is reduced
A The speed will increase abruptly
B The speed will increase in proportion to reduction in load
C The speed will remain almost/constant
D The speed will reduce
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
After driving for fifty kilo-meter, the driver suddenly realized that he has been driving in the wrong direction. Choose the wrong one following sentences.
A After
B realized
C has been driving
D in
After driving for twenty miles, he suddenly realized that he has benn driving in the wrong direction. Identify the word/phrase that must be changed in order for the sentences to be correct.
A After driving
B for
C realized
D has been driving
After driving (a) for twenty miles, he suddenly realized (b) that he has been driving (c) in (d) the wrong direction.
A a
B b
C c
D d
A moving-coil permanent-magnet instrument can be used as _____ by using a low resistance shunt.
A ammeter
B voltmeter
C flux-meter
D ballistic galvanometer
Starters are used with D.C. motors because
A These motors have high starting torque
B These motors are not self-starting
C Back e.m.f. of these motors is zero initially
D To restrict armature current as there is no back e.m.f. while starting

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