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 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 both Eb and Td are unchanged Eb is unchanged, but Td is zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 48.0%. 59.2%. 57.1%. 88.8%. 48.0%. 59.2%. 57.1%. 88.8%. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole 50 Hz induction motor is running at 1470 rpm. What is the slip value? 0.2 0.02 0.04 0.4 0.2 0.02 0.04 0.4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A synchronous machine has P number of poles, find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm)? ωe = P*ωm ωe = ωm ωe = P/2*ωm ωe = 2/P*ωm ωe = P*ωm ωe = ωm ωe = P/2*ωm ωe = 2/P*ωm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC motor operating at rated speed, the speed of the motor will Remain unaltered. Oscillate around the normal speed. Increase. Reduce. Remain unaltered. Oscillate around the normal speed. Increase. Reduce. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole DC generator runs at 750 rpm and generate an emf of 240 V. The armature is wave wound and has 792 conductors. If the total flux from each pole is 0.0145 Wb. What is the leakage co-efficient? 1.8. 1.5. 1.2. 1.4. 1.8. 1.5. 1.2. 1.4. ANSWER DOWNLOAD EXAMIANS APP
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