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
The capacitors used in single-phase capacitor motors have no__________?
(A) voltage rating
(B) dielectric medium
(C) polarity marking
(D) definite value
If a D.C. series motor is operated on A.C. supply, it will____________?
(A) spark excessively
(B) have poor efficiency
(C) have poor power factor
(D) all of the above
In a A.C. series motor armature coils are usually connected to commutator____________?
(A) through resistance
(B) through reactances
(C) through capacitors
(D) solidly
Which of the following motors has two separate windings on the motor ?
(A) Repulsion motor
(B) Repulsion induction motor
(C) Repulsion start induction run motor
(D) None of the above
A shaded pole motor does not possess___________?
(A) centrifugal switch
(B) capacitor
(C) commutator
(D) all of the above
The standard full-load power factor ratings for synchronous motors are___________?
(A) zero or 0.8 leading
(B) unity or 0.8 lagging
(C) unity or 0.8 leading
(D) unity or zero
The rotor copper losses, in a synchronous motor, are met by____________?
(A) d.c. source
(B) armature input
(C) motor input
(D) supply lines
A synchronous motor will always stop when:______________?
(A) supply voltage fluctuates
(B) load in motor varies
(C) excitation winding gets disconnected
(D) supply voltage frequency changes
The speed regulation of a synchronous motor is always___________?
(A) 1%
(B) 0.5%
(C) positive
(D) zero