Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 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. 1 at 90°C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Short circuiting is caused in the armature winding due to any of above. failure of insulation between two turns of coil. grounding of two or more turns of the same coil. failure of insulation between two commutator bars. any of above. failure of insulation between two turns of coil. grounding of two or more turns of the same coil. failure of insulation between two commutator bars. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which transformer, the tertiary winding is used? Star - delta Star - star Delta - star Delta - delta Star - delta Star - star Delta - star Delta - delta ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 250 V DC generator in run at rated speed with no excitation. The open circuit voltage will be about 100 V. 250 V. zero. very small, say about 2 or 3 V. about 100 V. 250 V. zero. very small, say about 2 or 3 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an AC servomotor has one of its winding excited by AC, then voltage measured at the other winding with rotor running will be proportional to rotor speed. proportional to square of rotor speed. zero. constant independent of speed. proportional to rotor speed. proportional to square of rotor speed. zero. constant independent of speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two mechanically coupled alternators deliver power at 50 Hz and 60 Hz respectively. The highest speed of the alternators is 500 rpm. 600 rpm. 3600 rpm. 3000 rpm. 500 rpm. 600 rpm. 3600 rpm. 3000 rpm. ANSWER DOWNLOAD EXAMIANS APP
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