A. varying field flux with tapped field windings
B. connecting rheostat in series
C. applying variable voltage by means of silicon controlled rectifier
D. applying variable voltage by means of variable auto-transformer
E. all of the above methods
Related Mcqs:
- In case of high speed universal motor which of the following needs more attention?
A. End play
B. Air gap
C. Insulation in rotor
D. Balancing of rotor - The speed of a universal motor is generally reduced by using_________?
A. gear trains
B. V-belts
C. brakes
D. chains - The speed of a universal motor is usually reduced by using____________?
A. gearing
B. belts
C. brakes
D. chains - The speed control of universal motor used for sewing machines is by____________?
A. friction
B. varying the resistance
C. tapping the field
D. centrifugal mechanism - The speed/load characteristics of a universal motor is same as that of_____________?
A. A.C. motor
B. D.C. shunt motor
C. D.C. series motor
D. none of the above - In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will_____________?
A. become unstable
B. draw excessive armature current and may burn out
C. fall out of synchronism and come to stand still
D. run as induction motor - A universal motor can run on___________?
A. A.C. only
B. D.C. only
C. either A.C. or D.C.
D. none of the above - The direction of rotation of universal motor can be reversed the by reversing the flow of current through__________?
A. armature winding
B. field winding
C. either armature winding or field winding
D. none of the above - In a universal motor, the most common cause of brush sparking is___________?
A. open armature winding
B. shorted armature winding
C. shorted field winding”
D. high commutator mica
E. all of the above - A universal motor is one which______________?
A. can be operated either on D.C. or A.C. supply at approximately the same speed and output
B. can be marketed internationally
C. runs at dangerously high speed on no-load
