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% 25% 5% 2% 4% 25% 5% 2% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a DC Shunt Motor having armature resistance of 0.5 Ω and 2 A armature current at no-load, when the armature current is changed to 20 A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load? 1130 r.p.m. 1037.5 r.p.m. 4575.4 r.p.m. none of above. 1130 r.p.m. 1037.5 r.p.m. 4575.4 r.p.m. none of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The synchronous reactance( Xs) is the reactance due to armature reaction of the machine reactance either due to armature reaction or leakage flux reactance due to leakage flux combined reactance due to armature reaction and leakage flux reactance due to armature reaction of the machine reactance either due to armature reaction or leakage flux reactance due to leakage flux combined reactance due to armature reaction and leakage flux ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the speed control of dc motors : 1. ward-leonard method is suitable forconstant-torque drives 2. Ward-leonard method is suitable for constant-power drives 3. field-control method facilitates speed control below base speed 4. Armature-resistance control method is more efficient than ward-leanard method 5. Field-control method is suitable for constant-torque drives 6. Armature-resistance control method is suitable for constant-torque drives From these, the correct answer is 1, 4, 6 1, 3, 5 1, 2, 6 1, 2, 5 1, 4, 6 1, 3, 5 1, 2, 6 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an AC servomotor has one of its winding excited by AC, then voltage measured at the other winding with rotor running will be zero. proportional to square of rotor speed. constant independent of speed. proportional to rotor speed. zero. proportional to square of rotor speed. constant independent of speed. proportional to rotor speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Cogging and crawling are phenomena associated with cage induction machines and they are essentially the same. any of the above. the former at a fraction of its rate speed and the latter during starting. the former during starting and the latter at a fraction of its rated speed. cage induction machines and they are essentially the same. any of the above. the former at a fraction of its rate speed and the latter during starting. the former during starting and the latter at a fraction of its rated speed. ANSWER DOWNLOAD EXAMIANS APP
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