Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 1 at 90°C. 3 at 90°C. 0.5 at 90°C. 2 at 90°C. 1 at 90°C. 3 at 90°C. 0.5 at 90°C. 2 at 90°C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of DC Shunt Motor, the speed will____ if the voltage increases, neglecting armature saturation. increase be unpredictable. decrease. remain the same. increase be unpredictable. decrease. remain the same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A smaller air gap in a polyphase induction motor helps to reduce the magnetizing current. increase the starting torque. reduce the chance of crawling. reduce the chance of cogging. reduce the magnetizing current. increase the starting torque. reduce the chance of crawling. reduce the chance of cogging. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements, 2, 3 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct 1 and 4 are correct 2, 3 and 4 are correct 1, 2 and 4 are correct 1, 2 and 3 are correct 1 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Dynamic braking is employed to brake non reversing drive None of these reversing drive both 1 and 2 non reversing drive None of these reversing drive both 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For 250 volt DC Shunt Motor the armature and field resistance are 0.5 ohm and 250 ohm respectively. What will be the back e.m.f. produced when it takes a load current of 21A. 280 V. 150 V. 220 V. 240 V. 280 V. 150 V. 220 V. 240 V. ANSWER DOWNLOAD EXAMIANS APP
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