Electrical Machines A dc shunt motor has external resistance Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping Ra maximum and Rf minimum Rf maximum and Ra minimum Ra maximum and Rf maximum Ra minimum and Rf minimum Ra maximum and Rf minimum Rf maximum and Ra minimum Ra maximum and Rf maximum Ra minimum and Rf minimum ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, the field system has to be provided on stator unlike synchronous machines Where in it could be on any member, because commutator action is not possible otherwise it reduces field structure iron losses dc machines are comparatively low rating machines. it gives more uniform air-gap flux distribution commutator action is not possible otherwise it reduces field structure iron losses dc machines are comparatively low rating machines. it gives more uniform air-gap flux distribution 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 = 301 A, secondary = 22.7 A primary = 11.4 A, secondary = 301 A primary = 602 A, secondary = 22.7 A primary = 22.7 A, secondary = 602.4 A primary = 301 A, secondary = 22.7 A primary = 11.4 A, secondary = 301 A primary = 602 A, secondary = 22.7 A primary = 22.7 A, secondary = 602.4 A ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Universal motors are used in food processing All of these traction cranes food processing All of these traction cranes 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. Full load current. Starting torque, operating speed, full load current. Operating speed. Starting torque. Full load current. Starting torque, operating speed, full load current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 3 1, 2, 3 and 4 3 only 1, 2 and 3 1, 3 1, 2, 3 and 4 3 only 1, 2 and 3 ANSWER DOWNLOAD EXAMIANS APP
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