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 three times the original value remain the same as the original changes to 0.5 times the original value changes to 1.5 times the original value changes to three times the original value remain the same as the original changes to 0.5 times the original value ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines which of the following losses are negligible in blocked rotor test? both A and B iron loss copper loss mechanical loss both A and B iron loss copper loss mechanical loss ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The counter (or back) emf in a dc machine is 1. the same as generated emf in a dc motor 2. proportional to field flux and armature speed 3. not the same as generated emf in a dc motor 4.inversely proportional to field flux 5. proportional to number of armature conductors 6. constant from no load to full load From these, the correct answer is 1, 2, 5 2, 4, 5, 6 3, 4, 5 2, 3, 6 1, 2, 5 2, 4, 5, 6 3, 4, 5 2, 3, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines which of the following type of brush and their application is/are correct carbon brush → normal ratings All of these electro graphite → large ratings copper graphite → low voltage high current density carbon brush → normal ratings All of these electro graphite → large ratings copper graphite → low voltage high current density ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When a DC cummulative compound wound motor is loaded Torque decrease and speed increases. Torque increase and speed decrease. Torque and speed both increase. Both torque and speed decrease. Torque decrease and speed increases. Torque increase and speed decrease. Torque and speed both increase. Both torque and speed decrease. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Secondary winding of an auto transformer is also called compensating winding. common winding. damping winding. tertiary winding. compensating winding. common winding. damping winding. tertiary winding. ANSWER DOWNLOAD EXAMIANS APP
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