Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 2 at 90°C. 3 at 90°C. 0.5 at 90°C. 1 at 90°C. 2 at 90°C. 3 at 90°C. 0.5 at 90°C. 1 at 90°C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature mmf in a dc machine is 1. stationary with respect to field poles 2. stationary with respect to armature 3. rotating with respect to field poles 4. rotating with respect to armature From these, the correct answer is 2, 3 1, 4 1, 3 2, 4 2, 3 1, 4 1, 3 2, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 3 , 5 1, 3, 5 1, 4 2, 4 ,5 2, 3 , 5 1, 3, 5 1, 4 2, 4 ,5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The shaft of induction motor may be unbalanced due to uneven air gap. overheating of winding. poor lubrication. overload. uneven air gap. overheating of winding. poor lubrication. overload. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the full form of MNP? Magnetic field neutral pole. Magnetic field neutral plane. Magnetic neutral plane. Magnetic neutral pole. Magnetic field neutral pole. Magnetic field neutral plane. Magnetic neutral plane. Magnetic neutral pole. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In V/f speed control of 3-phase induction motor, with increase in frequency, the slip at which maximum torque occurs increase. None of these decrease. either of these. increase. None of these decrease. either of these. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS