Electrical Machines Hunting phenomenon is observed in which motor? Induction motor. Both A and C. DC motor. Synchronous motor. Induction motor. Both A and C. DC motor. Synchronous motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum allowable moisture content of power transformer insulating oil is generally taken as 20 ppm. 35 ppm. 45 ppm. 25 ppm. 20 ppm. 35 ppm. 45 ppm. 25 ppm. 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% 78.5% 67.5% 72.5% 82.5% 78.5% 67.5% 72.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of DC Shunt Motor electromagnetic torque developed is Proportional to the square of armature current. Proportional to the armature current. Inversely proportional to the armature current. None of above. Proportional to the square of armature current. Proportional to the armature current. Inversely proportional to the armature current. None of above. 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, 2, 6 1, 3, 5 1, 4, 6 1, 2, 5 1, 2, 6 1, 3, 5 1, 4, 6 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of induction motors the ratio of length to pole pitch for minimum cost, is taken as 3 to 5. 1.0. 1.5 to 2. 2 to 3. 3 to 5. 1.0. 1.5 to 2. 2 to 3. ANSWER DOWNLOAD EXAMIANS APP
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