Electrical Machines Which of the following is done in speed control of DC motor by field flux control? Inserting resistance to armature circuit and field circuit. Inserting an additional resistance in the armature circuit. Inserting an additional resistance in the field circuit. Any of above. Inserting resistance to armature circuit and field circuit. Inserting an additional resistance in the armature circuit. Inserting an additional resistance in the field circuit. Any of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines DC series motor is best suited for electric traction as It consume less power. It is cheaper in cost. It develops high starting torque. It runs at very high speed at light load. It consume less power. It is cheaper in cost. It develops high starting torque. It runs at very high speed at light load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines On which of the following factor/factors the speed of a DC motor depends upon? Applied voltage. Armature current. All of these. Field flux. Applied voltage. Armature current. All of these. Field flux. 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%. 72.5% 78.5% 67.5% 82.5% 72.5% 78.5% 67.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 2 pole synchronous machine is operating at 3000 rpm. Find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm) ? ωe = ωm ωe = 4*ωm ωe = 1/2*ωm ωe = 2*ωm ωe = ωm ωe = 4*ωm ωe = 1/2*ωm ωe = 2*ωm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is not a necessary condition to be satisfied for synchronising an incoming alternator to an already operating alternator? same prime mover speed same voltage magnitude same phase sequence same frequency same prime mover speed same voltage magnitude same phase sequence same frequency ANSWER DOWNLOAD EXAMIANS APP
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