246. A universal motor operates on
A. synchronous speed with varying load
B. constant load and verying speed
C. approximately constant speed and load
D. constant speed and varying load
247. In a split-phase motor the ratio of number of turns for starting winding to that for running winding is
A. less than one
B. more than one
C. one
D. two
248. In a hysteresis motor, the rotor
A. has high hysteresis loss
B. has high retentivity
C. is made of chrome steel
D. should have all of the above features
249. In a universal motor, normally the ratio of width of brush to the width of comutator segments is
A. 6 : 1
B. 4 : 1
C.(d) 1 : 1
D.(c) 2 : 1
250. Shading coils,in case of a shaded pole motor, are used to
A. protect against sparking
B. reduce windage losses
C. reduce friction losses
D. produce rotating magnetic field.
251. In a shaded pole motor, the direction of rotation is from
A. shadedpole to main pole
B. main pole to shaded pole
C. depends on supply line polarity
D. none of the above
252. Which motor has unsymmetrical rotor?
A. Shaded-pole motor
B. Split-phase motor
C. Reluctance motor
D. Universal motor
Page 36 of 54