quiz for electrical classes

In a power plant, a synchronous generator rotates at 3000 RPM to produce 500MW of electric power. What would be the speed if the power is increased to 700MW?

Hmmm, let me think about that....

For a synchronous generator (Alternator) the speed is constant. If you change the speed you change the frequency.
In order to get more power from you alternator you need more mechancial power because the Alternator is just a converter. It converts mechanical energy to electrical energy. With that being said - as you load the alternator the output voltage will drop. To keep the output voltage constant you need to increase flux which will increase the generated voltage. Do not confused generated voltage with output voltage. All generators and Alternators experienced internal voltage drop. Nothing you can do about it except to compensate for it. At some point the core material will saturate (magnetically) and you will not be able to increase the generated voltage. So you have reached the maximum output power. Again please note that the speed is held contant because you want a fixed frequency. If you play with speed then you are also playing with output voltage as voltage is also a function of speed just as is frequency. that is why we hold speed and voltage fixed. They interact.

can u get me any possible answer for these question

by ratio and proportion answer should be 4200 RPM

can u show me the equation please?

RPM2/RPM1 = POWER2/POWER1

RPM2=(RPM1*POWER2)/POWER1

what about the new voltage and new frequency ???

Ought to add those to the QUIZ too