Electrical Machines If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated) changes to 1.5 times the original value changes to 0.5 times the original value changes to three times the original value remain the same as the original changes to 1.5 times the original value changes to 0.5 times the original value changes to three times the original value remain the same as the original ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3-phase induction motor, torque and supply voltage are related as T ∝ 1/V T ∝ V T ∝ 1/V² T∝ V² T ∝ 1/V T ∝ V T ∝ 1/V² T∝ V² ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the field of a dc shunt motor gets opened while the motor is running, then the armature current will drop motor will become slow. motor will attain dangerously high speed armature will oscillate about original speed as the mean speed armature current will drop motor will become slow. motor will attain dangerously high speed armature will oscillate about original speed as the mean speed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The maximum possible speed at which an alternator can be driven to generate 50 Hz and 4000 V is 1500 rpm. 3600 rpm. 3000 rpm. 4000 rpm. 1500 rpm. 3600 rpm. 3000 rpm. 4000 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of rotation of 5th harmonic component in the stator of an induction motor is (1 / 15) times the synchronous speed. (1 / 5) times the synchronous speed. 0.5 times the synchronous speed. 5 times the synchronous speed. (1 / 15) times the synchronous speed. (1 / 5) times the synchronous speed. 0.5 times the synchronous speed. 5 times the synchronous speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer core is made up of a silicon steel laminations which has maximum flux density 1 Tesla. If it was cold rolled grain oriented its flux density increases to 1.6 Tesla. What is the saving in core size or area due to cold rolled grain oriented process? 60% 68% 40% 38% 60% 68% 40% 38% ANSWER DOWNLOAD EXAMIANS APP
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