Electrical Machines Counter emf of a DC motor exceeds supply voltage aids applied voltage. regulates its armature voltage. helps in energy conversion. exceeds supply voltage aids applied voltage. regulates its armature voltage. helps in energy conversion. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a three phase star - delta transformer, what is the angle difference between primary and secondary phase voltages? Delta side lags by -30°. Delta side leads by 30°. Star side leads by 30°. Star side lags by -30°. Delta side lags by -30°. Delta side leads by 30°. Star side leads by 30°. Star side lags by -30°. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines DC shunt motors are suitable for All of this. Lathes. Blowers and fans. Centrifugal pumps All of this. Lathes. Blowers and fans. Centrifugal pumps 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%. 78.5% 72.5% 67.5% 82.5% 78.5% 72.5% 67.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To avoid formation of grooves in the commutator the brushes of same polarity should track each other. brush position has no effect on the commutator grooving. the brushes of opposite polarity should track each other. None of these the brushes of same polarity should track each other. brush position has no effect on the commutator grooving. the brushes of opposite polarity should track each other. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor runs at a no-load speed of 1140 rpm. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full-load speed in rpm is 1000 1200 1080 1203 1000 1200 1080 1203 ANSWER DOWNLOAD EXAMIANS APP
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