Electrical Machines The armature voltage control is considered suitable for a DC motor driven at constant current. power. torque. speed. current. power. torque. speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The main purpose of providing tertiary winding in a three phase transformer is None of these to suppress harmonic and unbalance in voltage. to carry extra load. to interconnect three voltage systems. None of these to suppress harmonic and unbalance in voltage. to carry extra load. to interconnect three voltage systems. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 78.5% 67.5% 82.5% 72.5% 78.5% 67.5% 82.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm. Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque. Assume losses to be constant. 74 Nm. 38.5 Nm. 27.73 Nm . 65.8 Nm. 74 Nm. 38.5 Nm. 27.73 Nm . 65.8 Nm. 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 it gives more uniform air-gap flux distribution commutator action is not possible otherwise dc machines are comparatively low rating machines. it reduces field structure iron losses it gives more uniform air-gap flux distribution commutator action is not possible otherwise dc machines are comparatively low rating machines. it reduces field structure iron losses ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When pure inductive load is connected to the alternator, what is the effect of armature reaction? Cross magnetization Magnetization Demagnetization None of these Cross magnetization Magnetization Demagnetization None of these ANSWER DOWNLOAD EXAMIANS APP
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