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 maximum Ra maximum and Rf minimum Ra minimum and Rf minimum Rf maximum and Ra minimum Ra maximum and Rf maximum Ra maximum and Rf minimum Ra minimum and Rf minimum Rf maximum and Ra minimum ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Capacitor in split phase induction motor is used to reduce the harmonics. start the motor. improve the power factor. improve the starting torque. reduce the harmonics. start the motor. improve the power factor. improve the starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.512. 0.649. 0.443. 0.573. 0.512. 0.649. 0.443. 0.573. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines High inrush of current during a starting of DC motor can efficiently be restricted to a safer value by increasing the _________________ resistance. both A and B armature circuit shunt field none of above both A and B armature circuit shunt field none of above 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 worsen and terminal voltage will rise. improve and terminal voltage will rise . worsen and terminal voltage will fall improve but terminal voltage will fall. worsen and terminal voltage will rise. improve and terminal voltage will rise . worsen and terminal voltage will fall improve but terminal voltage will fall. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA 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 speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM ANSWER DOWNLOAD EXAMIANS APP
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