Electrical Machines Maximum allowable moisture content of power transformer insulating oil is generally taken as 20 ppm. 45 ppm. 35 ppm. 25 ppm. 20 ppm. 45 ppm. 35 ppm. 25 ppm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If a DC Series motor is connected across an AC supply it will burn. run at lower speed. not run. run at normal speed. burn. run at lower speed. not run. run at normal speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is 3/4. 9/16. 16/9. 4/3. 3/4. 9/16. 16/9. 4/3. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 1, 2, 3 2, 3 ,5 2, 3, 4 2, 3, 4, 5 1, 2, 3 2, 3 ,5 2, 3, 4 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following methods of speed control is not affected through stator side? Change of supply frequency. Change of number of pole. Change of supply voltage. Change of rotor resistance. Change of supply frequency. Change of number of pole. Change of supply voltage. Change of rotor resistance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Flashing the field of DC generator means neutralising residual magnetism. creating residual magnetism by a DC source. increasing flux density by adding extra turns of winding. making the magnetic losses forces parallel. neutralising residual magnetism. creating residual magnetism by a DC source. increasing flux density by adding extra turns of winding. making the magnetic losses forces parallel. ANSWER DOWNLOAD EXAMIANS APP
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