Electrical Machines A dc series motor driving and electric train faces a constant power load. It is running at rated speed and rated voltage. If the speed has to be brought down to 0.25 p.u. the supply voltage has to be approximately brought down to 0.75 p.u 0.125 p.u 0.5 p.u 0.25 p.u 0.75 p.u 0.125 p.u 0.5 p.u 0.25 p.u ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two mechanically coupled alternators deliver power at 50 Hz and 60 Hz respectively. Highest speed of alternator is 500 rpm. 600 rpm. 3000 rpm. 3600 rpm. 500 rpm. 600 rpm. 3000 rpm. 3600 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Commutator in DC generator is used for increase efficiency convert AC armature current in to DC reduce losses collecting of current increase efficiency convert AC armature current in to DC reduce losses collecting of current ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a single phase transformer the magnitude of leakage reactance is twice that of resistance of both primary and secondary. With secondary short circuited, the input power factor is 2/√5 1/√2 1/3 1/√5 2/√5 1/√2 1/3 1/√5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The air gap between the yoke and armature is dc machine is kept very small to achieve a stronger magnetic field. to avoid over heating. All of these to avoid locking of the armature. to achieve a stronger magnetic field. to avoid over heating. All of these to avoid locking of the armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motor the 7th harmonic torque may make the motor rotate at (1 / 7)th synchronous speed. This is called resonance. harmonics. cogging. crawling. resonance. harmonics. cogging. crawling. ANSWER DOWNLOAD EXAMIANS APP
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