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 0.25 p.u 0.5 p.u 0.125 p.u 0.75 p.u 0.25 p.u 0.5 p.u 0.125 p.u ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ? 2 alone 1, 2 and 3 1 and 2 1 and 3 2 alone 1, 2 and 3 1 and 2 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-phase, 2 pole, 12 slot synchronous machine is operating at synchronous speed. Find the slot angle? 18° 60° 20° 30° 18° 60° 20° 30° ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two single-phase alternators operating in parallel have induced EMFs on open circuit of 230∠0° and 230∠10° volts and respective reactance of j2 Ω j3 Ω calculate the terminal voltage 200 V. 300 V. 150 V. 223.V. 200 V. 300 V. 150 V. 223.V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The interpoles in dc machines have a tapering shape in order to reduce the overall weight reduce the saturation in the interpole increase the acceleration of commutation economise on the material required for interpoles and their windings reduce the overall weight reduce the saturation in the interpole increase the acceleration of commutation economise on the material required for interpoles and their windings ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in a DC machine is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. is in direct opposition to the main poles. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. is in direct opposition to the main poles. ANSWER DOWNLOAD EXAMIANS APP
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