Electrical Machines In a DC generator, if P be the number of poles and N be the rpm of the rotor, then frequency of magnetic reversals will be PN/2. PN/60. PN/3000. PN/120. PN/2. PN/60. PN/3000. PN/120. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines With the increases in field excitation of a DC generator, its generated emf increases. increases upto a limit and then remains almost constant. remains constant. decreases. increases. increases upto a limit and then remains almost constant. remains constant. decreases. 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%. 82.5% 67.5% 78.5% 72.5% 82.5% 67.5% 78.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines During hunting of a synchronous motor field excitation increases. negative phase sequence currents are generated. harmonic are developed in the armature circuit. damper bar develops torque. field excitation increases. negative phase sequence currents are generated. harmonic are developed in the armature circuit. damper bar develops torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A voltmeter gives 120 oscillations per minute when connected to the rotor of an induction motor. The frequency is 50Hz. The slip of the motor is 4% 5% 25% 2% 4% 5% 25% 2% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Rotating magnetic field is produced in an induction motor because of stator winding. rotor winding. either stator winding or rotor winding. None of these stator winding. rotor winding. either stator winding or rotor winding. None of these ANSWER DOWNLOAD EXAMIANS APP
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