Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque 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% 72.5% 67.5% 82.5% 78.5% 72.5% 67.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum power will be developed when back emf is half of the supply voltage. double the supply voltage. equal to supply voltage. All of these half of the supply voltage. double the supply voltage. equal to supply voltage. All of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To increase starting torque of a 3-phase slip ring induction motor, preferred method is to increase rotor resistance supply frequency None of these supply voltage rotor resistance supply frequency None of these supply voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC generator, the ripples in the direct emf generated are reduced by employing graphite brushes. commutator with large number of segments. carbon brushes. equalizer rings. graphite brushes. commutator with large number of segments. carbon brushes. equalizer rings. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in dc machine provide ----------------- rectification? full wave half wave full wave controlled half wave controlled full wave half wave full wave controlled half wave controlled ANSWER DOWNLOAD EXAMIANS APP
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