Electrical Machines In a single phase transformer the magnitude of leakage reactance is twice that of resistance of both primary and secondary. With secondary short circuited, the input power factor is 2/√5 1/√5 1/3 1/√2 2/√5 1/√5 1/3 1/√2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines With the increase in speed of DC motor Back emf falls and line current increase. Both back emf as well as line current fall. Back emf increase but line current falls. Both back emf as well as line current increase. Back emf falls and line current increase. Both back emf as well as line current fall. Back emf increase but line current falls. Both back emf as well as line current increase. 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% 82.5% 67.5% 72.5% 78.5% 82.5% 67.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Rotating magnetic field is produced in an induction motor because of either stator winding or rotor winding. rotor winding. stator winding. None of these either stator winding or rotor winding. rotor winding. stator winding. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Secondary winding of an auto transformer is also called compensating winding. damping winding. tertiary winding. common winding. compensating winding. damping winding. tertiary winding. common winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC generators, the cause of rapid brush wear may be rough commutator surface. severe sparking. imperfect contact. any of above. rough commutator surface. severe sparking. imperfect contact. any of above. ANSWER DOWNLOAD EXAMIANS APP
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