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 Eb is unchanged, but Td is zero both Eb and Td are zero both Eb and Td are unchanged Eb is zero, but Td is unchanged Eb is unchanged, but Td is zero both Eb and Td are zero both Eb and Td are unchanged Eb is zero, but Td is unchanged ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will improve but terminal voltage will fall. worsen and terminal voltage will fall worsen and terminal voltage will rise. improve and terminal voltage will rise . improve but terminal voltage will fall. worsen and terminal voltage will fall worsen and terminal voltage will rise. improve and terminal voltage will rise . ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two transformers with identical rating, are designed with flux densities of 1.2 and 1.4 Wb / m2 respectively. The weight of first transformer per kVA is equal to that of second transformer. less than that of second transformer. more than that of second transformer. none of these. equal to that of second transformer. less than that of second transformer. more than that of second transformer. none of these. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the source voltage of a DC motor is increased, which of the following will decrease? Operating speed. Starting torque, operating speed, full load current. Full load current. Starting torque. Operating speed. Starting torque, operating speed, full load current. Full load current. Starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The synchronous speed of an induction motor will be increased by speed can not be increased. increasing number of poles. increasing of frequency. decreasing of frequency. speed can not be increased. increasing number of poles. increasing of frequency. decreasing of frequency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a DC Shunt Motor having armature resistance of 0.5 Ω and 2A armature current at no-load, when the armature current is changed to 20A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load? 1037.5 r.p.m. 4575.4 r.p.m. 1130 r.p.m. 963.8 r.p.m. 1037.5 r.p.m. 4575.4 r.p.m. 1130 r.p.m. 963.8 r.p.m. ANSWER DOWNLOAD EXAMIANS APP
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