The purpose of using short-circuit gear is___________?
(A) to short circuit the rotor at slip rings
(B) to short circuit the starting resistances in the starter
(C) to short circuit the stator phase of motor to form star
(D) none of the above
Temperature of the stator winding of a three phase induction motor is obtained by___________?
(A) resistance rise method
(B) thermometer method
(C) embedded temperature method
(D) all above methods
For driving high inertia loads best type of induction motor suggested is_____________?
(A) slip ring type
(B) squirrel cage type
(C) any of the above
(D) none of the above
Insertion of resistance in the rotor of an induction motor to develop a given torque?
(A) decreases the rotor current
(B) increases the rotor current
(C) rotor current becomes zero
(D) rotor current rernains same
Insertion of reactance in the rotor circuit_______?
(A) reduces starting torque as well as maximum torque
(B) increases starting torque as well as maximum torque
(C) increases starting torque but maxi-mum torque remains unchanged
(D) increases starting torque but maxi-mum torque decreases
The low power factor of induction motor is due to___________?
(A) rotor leakage reactance
(B) stator reactance
(C) the reactive lagging magnetizing current necessary to generate the magnetic flux
(D) all of the above
In induction motor, percentage slip depends on__________?
(A) supply frequency
(B) supply voltage
(C) copper losses in motor
(D) none of the above
When /?2 is the rotor resistance, .X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running conditions will be_____________?
(A) sR2X2 = 1
(B) sR2 = X2
(C) R2 = sX2
(D) R2 = s2X2
In a capacitor start motor, the phase displacement between starting and running winding can be nearly__________?
(A) 10°
(B) 30°
(C) 60°
(D) 90°
Which of the following motor will give relatively high starting torque ___________?
(A) Capacitor start motor
(B) Capacitor run motor
(C) Split phase motor
(D) Shaded pole motor