Electrical Machines Which of the following methods are used to control the speed of DC motors is All of these armature circuit resistance control field current control supply voltage control All of these armature circuit resistance control field current control supply voltage control ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC machines, the interpoles are provided both (B) and (C). to make commutation spark less. to counteract demagnetizing effect of armature mmf in commutating zone. to counteract the reactance voltage and the cross-magnetizi both (B) and (C). to make commutation spark less. to counteract demagnetizing effect of armature mmf in commutating zone. to counteract the reactance voltage and the cross-magnetizi ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a dc machine, 1. physically, the brush axis is along the direct axis 2. physically, the brush axis is along the interpolar axis 3. schematically, the brush axis is along the direct axis 4. schematically, the brush axis is along the quadrature axis 5. armaturemmf is directed along the brush axis From these, the correct statements are 1 , 3, 5 1, 4,5 2, 4, 5 2, 3, 5 1 , 3, 5 1, 4,5 2, 4, 5 2, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 230 V, 50 Hz, 4 pole single phase induction motor is rotating in the clockwise ( forward ) direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 Ω. Then the effective rotor resistance in the backward branch of the equivalent circuit will be 2 Ω. 10 Ω. 8 Ω. 4 Ω. 2 Ω. 10 Ω. 8 Ω. 4 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Wave winding is prefered for which of the following rating? low current and high voltage low current and low voltage high current and high voltage high current and low voltage low current and high voltage low current and low voltage high current and high voltage high current and low voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motor the 7th harmonic torque may make the motor rotate at (1 / 7)th synchronous speed. This is called cogging. resonance. crawling. harmonics. cogging. resonance. crawling. harmonics. ANSWER DOWNLOAD EXAMIANS APP