Electrical Machines As compared to DOL starting, a cage induction motor with star-delta starting shall have more starting time. more starting torque. smoother acceleration. reduced starting current. more starting time. more starting torque. smoother acceleration. reduced starting current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of 400 V. 800 V. 200 V. 100 V. 400 V. 800 V. 200 V. 100 V. 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, 4, 6 1, 2, 5 1, 2, 6 1, 3, 5 1, 4, 6 1, 2, 5 1, 2, 6 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A single phase transformer has specifications as 250 KVA, 11000 V/415 V, 50 Hz. What are the values of primary and secondary currents? primary = 11.4 A, secondary = 301 A primary = 22.7 A, secondary = 602.4 A primary = 602 A, secondary = 22.7 A primary = 301 A, secondary = 22.7 A primary = 11.4 A, secondary = 301 A primary = 22.7 A, secondary = 602.4 A primary = 602 A, secondary = 22.7 A primary = 301 A, secondary = 22.7 A ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero Eb is zero, but Td is unchanged ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 1, 2, 3, 4 1, 2, 5 2, 3, 4 1, 3, 5 1, 2, 3, 4 1, 2, 5 2, 3, 4 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
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