Electrical Machines For the speed control of polyphase squirrel cage induction motor, if frequency of operation is decreased with None of these constant supply voltage V, starting torque Tst decreases either of these constant V, Tst increases None of these constant supply voltage V, starting torque Tst decreases either of these constant V, Tst increases ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the emf generated by a 4 pole Lap connected DC Motor rotating at 1500 rpm having 1000 conductors and useful flux per pole is 0.4 mWb. 20 volts. 30 volts. 10 volts. 40 volts. 20 volts. 30 volts. 10 volts. 40 volts. 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%. 72.5% 82.5% 67.5% 78.5% 72.5% 82.5% 67.5% 78.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of a compensated DC series motor, the compensating winding is provided In series with the armature winding. As a separate unit. In parallel with the field winding. In parallel with the armature winding. In series with the armature winding. As a separate unit. In parallel with the field winding. In parallel with the armature winding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Damper winding is used to both 1 and 2. suppress the hunting. decrease the load current. increase the load current. both 1 and 2. suppress the hunting. decrease the load current. increase the load current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 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 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 ANSWER DOWNLOAD EXAMIANS APP
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