Speed control of a universal motor is achieved by__________?

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

Which of the following statements regarding hysteresis motor is in incorrect?

A. It is extremely sensitive to fluctuations in supply voltage
B. Its high starting torque is due to its high rotor hysteresis loss
C. It is extremely quiet in operation
D. It accelerates from rest to full-speed almost instantaneously

The starting winding of a single-phase motor is placed in_________?

A. Armature
B. Field
C. Rotor
D. Stator

The speed of a universal motor is usually reduced by using____________?

A. Gearing
B. Belts
C. Brakes
D. Chains

A reluctance motor____________?

A. Is self-starting
B. Is constant speed motor
C. Needs no d.c. excitation
D. All of the above

Which motor is normally free from mechanical and magnetic vibrations ?

A. Split phase motor
B. Universal motor
C. Hysteresis motor
D. Shaded pole motor

As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for__________?

A. Fans
B. Blowers
C. Sound equipment
D. Mixer grinders

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

When a D.C. series motor is connected to A.C. supply, the power factor will be low because of____________?

A. High inductance of field and armature circuits
B. Induced current in rotor due to variations of flux
C. Fine copper wire winding
D. None of the above

In which single-phase motor, the rotor has no teeth or winding ?

A. Split phase motor
B. Reluctance motor
C. Hysteresis motor
D. Universal motor