Electrical Machines Which of the following motor is more expensive for same KW output rating ? DC Shunt Motor Induction motor. AC single phase motor. Synchronous motor. DC Shunt Motor Induction motor. AC single phase motor. Synchronous motor. 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%. 67.5% 82.5% 78.5% 72.5% 67.5% 82.5% 78.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC motor operating at rated speed, the speed of the motor will Increase. Remain unaltered. Reduce. Oscillate around the normal speed. Increase. Remain unaltered. Reduce. Oscillate around the normal speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Flashing of DC generator means neutralization of residual magnetism. creation of residual magnetism by a DC source. None of these increasing flux density by providing extra ampere-turns in field. neutralization of residual magnetism. creation of residual magnetism by a DC source. None of these increasing flux density by providing extra ampere-turns in field. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 88.8%. 48.0%. 59.2%. 57.1%. 88.8%. 48.0%. 59.2%. 57.1%. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following motors has low ratings only? Capacitor run Shaded pole Resistance split phase Capacitor start Capacitor run Shaded pole Resistance split phase Capacitor start ANSWER DOWNLOAD EXAMIANS APP