Questions
61
Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a
Answer: magnetic relay
62
Centrifugal switch disconnects the auxiliary winding of the motor at about ____ percent of synchronous speed
Answer: 70 to 80
64
Which of the following motors is used in a situation where load increases with speed ?
Answer: Three-phase series motor
65
The motor used for the compressors is
Answer: capacitor-start capacitor-run motor
66
Which of the following motors is used for unity power factor ?
Answer: Schrage motor
67
The purpose of stator winding in the compensated repulsion motor is to
Answer: provide mechanical balance
68
The speed/load characteristics of a universal motor is same as that of
Answer: D.C. series motor
69
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it
Answer: helps in reducing the tendency of the rotor teeth to remain under the stator teeth
71
In a ceilingfan employing capacitor run motor
Answer: secondary winding surrounds the primary winding
72
Speed torque characteristic of a repulsion induction motor is similar to that of a D.C.
Answer: compound motor
73
If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in
Answer: damage to the starting winding
74
In repulsion motor, maximum torque is developed when
Answer: brush axis is at 45° electrical to the field axis
75
In split phase motor main winding is of
Answer: thick wire placed at the bottom of the slots
76
Torque developed by a single phase induction motor at starting is
Answer: nil
77
The speed control of universal motor used for sewing machines is by
Answer: varying the resistance
78
Which of the following applications always have some load whenever switched on ?
Answer: Pistol drills
