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 shaft must be able to with stand Any unbalanced magnetic pull on the armature core. All of these Twisting stains due to transmission of torque. Bending moment due to weight of the armature. Any unbalanced magnetic pull on the armature core. All of these Twisting stains due to transmission of torque. Bending moment due to weight of the armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A smaller air gap in a polyphase induction motor helps to increase the starting torque. reduce the chance of cogging. reduce the chance of crawling. reduce the magnetizing current. increase the starting torque. reduce the chance of cogging. reduce the chance of crawling. reduce the magnetizing current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ induction motor draws an current of 50 A from mains when starts by direct switching. If an auto transformer with 60 % tapping is used for starting the current drawn from the mains will be 80. 36. 18. 50. 80. 36. 18. 50. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which type of bearing is provided in small induction motors to support the rotor shaft? Bush bearings. None of these Cast iron bearings. Ball bearings. Bush bearings. None of these Cast iron bearings. Ball bearings. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines 1 KVA, 230 V, 50 Hz, single phase transformer has an eddy current loss of 30 watts. The eddy current loss when the transformer is excited by a dc source of same voltage will be less than 30 W more than 30 W zero watt 30 W less than 30 W more than 30 W zero watt 30 W ANSWER DOWNLOAD EXAMIANS APP
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