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
Most of the fractional horsepower motors have either___________?
(A) hard and annealed bearings
(B) ball or roller bearings
(C) soft and porous bearings
(D) plain or sleeve bearings
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
(D) all of the above
Which of the following statements regarding reluctance-start motor is incorrect ?
(A) It is similar to reluctance motor
(B) It is basically an induction motor and not a synchronous one
(C) So far as its basic working principle is concerned, it is similar to shaded pole motor
(D) the air-gap between rotor and salient poles is non- uniform
If starting winding of a single-phase induction motor is left in the circuit, it will____________?
(A) run faster
(B) spark at light loads
(C) draw excessive current and overheat
(D) run slower
If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then____________?
(A) motor will not come up to speed
(B) motor will not carry the load
(C) current drawn by the motor will be excessively high
(D) electrolytic capacitor will, in all probability, suffer break down
Which of the following statements regarding two value capacitor motor is incorrect ?
(A) It is a reversing motor
(B) It is preferred to permanent-split single-value capacitor motor where frequent reversals are required
(C) It has low starting as well as rushing currents
(D) It has high starting torque
If a single phase induction motor runs slower than normal, the most likely defect is_____________?
(A) worn bearings
(B) short-circuit in the winding
(C) open-circuit in the winding
(D) none of the above
Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________?
(A) it is comparatively cheaper
(B) it has almost non-destructible capacitor
(C) it has low starting as well as running currents at relatively high power factor
(D) it is quiet in operation
In case one phase of a three-phase synchronous motor is short-circuited the motor will____________?
(A) not start
(B) run at 2/3 of synchronous speed
(C) run with excessive vibrations
(D) take less than the rated load