Category: Polyphase Induction Motors

A. By changing the number of stator poles
B. Rotor rheostat control
C. By operating two motors in cascade
D. By injecting e.m.f. in the rotor circuit

A. supply frequency
B. supply voltage
C. copper losses in motor
D. none of the above

A. directly proportional to slip
B. inversely proportional to slip
C. proportional to the square of the slip
D. none of the above

A. to reduce the magnetic hum and locking tendency of the rotor
B. to increase the tensile strength of the rotor bars
C. to ensure easy fabrication
D. none of the above

A. the power factor will be low
B. windage losses will be more
C. bearing friction will reduce
D. copper loss will reduce In an induction motor

A. inadequate motor wiring
B. poorely regulated power supply
C. any one of the above
D. none of the above

A. humming
B. hunting
C. crawling
D. cogging

A. graphite
B. grease
C. mineral oil
D. molasses

A. in the opposite direction as the direction of the rotating field
B. in the same direction as the direction of the field
C. in any direction depending upon phase squence of supply

A. k/torque with direct switching
B. K x torque with direct switching
C. K2 x torque with direct switching
D. k2/torque with direct switching