Electrical Machines A DC motor with armature resistance of 0.5 ohms connected directly to a 220 Volt supply. If the armature is stationary then the current flowing through the armature is 570 A. 340 A. 440 A. 250 A. 570 A. 340 A. 440 A. 250 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a transformer the magnetic coupling between the primary and secondary winding can be increased by using the magnetic core of low reluctance. increasing the number of turns. using transformer oil of better quality. using soft material for winding. using the magnetic core of low reluctance. increasing the number of turns. using transformer oil of better quality. using soft material for winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of a 50 Hz three phase induction motor under full load condition is 725 rpm the number of poles of the motor are ______________. 2. 4. 6. 8. 2. 4. 6. 8. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the speed control of dc motors : 1. ward-leonard method is suitable forconstant-torque drives 2. Ward-leonard method is suitable for constant-power drives 3. field-control method facilitates speed control below base speed 4. Armature-resistance control method is more efficient than ward-leanard method 5. Field-control method is suitable for constant-torque drives 6. Armature-resistance control method is suitable for constant-torque drives From these, the correct answer is 1, 2, 5 1, 2, 6 1, 3, 5 1, 4, 6 1, 2, 5 1, 2, 6 1, 3, 5 1, 4, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Current in a coil undergoing commutation is not able to get reversed completely by the end of commutation period. It is due to armature emf. reactance voltage induced in the coil. coil resistance. None of these armature emf. reactance voltage induced in the coil. coil resistance. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What happens if fifth multiples of harmonics is given to induction motor? It will rotates in reverse direction. Fail to start. It will rotates in normal operation. Either short circuit or open circuit occurs. It will rotates in reverse direction. Fail to start. It will rotates in normal operation. Either short circuit or open circuit occurs. ANSWER DOWNLOAD EXAMIANS APP
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