Electrical Machines In a DC generator the actual flux distribution depends upon size of air gap. shape of the pole shoe. clearance between tips of the adjacent pole shoes. all of above. size of air gap. shape of the pole shoe. clearance between tips of the adjacent pole shoes. all of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The DC generator runs at a speed of 1000 rpm and flux per pole is 0.2 Wb, number of poles are 2 the winding is wave wound and having 480 conductors. The critical speed is 1200 rpm. Then the generated emf ( Eg ) 2000 Volt. 1600 Volt. 1500 Volt. 0 Volt. 2000 Volt. 1600 Volt. 1500 Volt. 0 Volt. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The maximum possible speed at which an alternator can be driven to generate 50 Hz and 4000 V is 3600 rpm. 4000 rpm. 1500 rpm. 3000 rpm. 3600 rpm. 4000 rpm. 1500 rpm. 3000 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 67.5% 72.5% 78.5% 82.5% 67.5% 72.5% 78.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole 50 Hz induction motor is running at 1470 rpm. Find the speed of stator magnetic field with respect to rotor? 1500 rpm zero 30 rpm 1470 rpm 1500 rpm zero 30 rpm 1470 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 ANSWER DOWNLOAD EXAMIANS APP
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