Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a___________?
(A) magnetic relay
(B) thermal relay
(C) centrifugal switch
(D) none of the above
Centrifugal switch disconnects the auxiliary winding of the motor at about ______ percent of synchronous speed?
(A) 30 to 40
(B) 70 to 80
(C) 80 to 90
(D) 100
Which of the following motors is used in a situation where load increases with speed ?
(A) Induction motor
(B) Three-phase series motor
(C) Schrage motor
(D) Hysteresis motor
Which of the following motors is used for unity power factor ?
(A) Hysteresis motor
(B) Schrage motor
(C) Universal motor
(D) Reluctance motor
In repulsion motor, zero torque is developed when___________?
(A) brush axis is 45° electrical to field axis
(B) brush axis coincides with the field axis
(C) brush axis is 90° electrical to field axis
(D) both
The motor used for the compressors is____________?
(A) d.c. series motor
(B) shaded pole motor
(C) capacitor-start capacitor-run motor
(D) reluctance motor
The purpose of stator winding in the compensated repulsion motor is to_____________?
(A) provide mechanical balance
(B) improve power factor and provide better speed regulation
(C) prevent hunting in the motor
(D) eliminate armature reaction
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it_____________?
(A) improves the efficiency
(B) helps the rotor teeth to remain under the stator teeth
(C) helps in reducing the tendency of the rotor teeth to remain under the stator teeth
(D) improves the power factor
In a ceilingfan employing capacitor run motor____________?
(A) secondary winding surrounds the primary winding
(B) primary winding surrounds the secondary winding
(C) both are usual arrangements
(D) none of the above
To reverse the direction of rotation of acapacitor start motor while it is running we should___________?
(A) disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding
(B) disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding
(C) reverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply
(D) reverse the direction of connections of the auxiliary winding and immediately connect it to supply