why can't we place a dynamo at the end of the fan so that used electricity can be regenerated.?

Question

this can be used to recover the lost energy.Please comment

Answer 1

Power in = Power out + Power losses

Power into the fan is electrical power V*I (voltage times current). Power out in mechanical terms is T*w (N*m torque times rotational speed in rads/sec). Your losses are those of friction/air, reactive losses in the coils, and I^2*R electrical losses.
IF you were to add another load to the shaft to generate electricity, it must be added to the right side of the upper equation, and require more initial input power. If more input power is not available, the fan would just be slower.

It has been suggested elsewhere to do this and feel the generated electricity back into the first motor. Even if these devices were 100% effecient with no losses, it wouldn't even be worth it. Thats like adding the same value to both sides of the upper equation.

Answer 2

It would likely require additional force (energy) to make the dynamo function. That, compounded by additional friction, would put a greater electrical demand upon the fan. Consequently, the
nominal amount of energy generated by the dynamo would be largely offset by the additional forces required, not to mention the lost heat energy created by the fan.

Answer 3

Not just regenerate, you can get electricity for free but you have to connect fan to power outlet in neighborhood.

Answer 4

the energy transfer should be quantified. you can not generate an equal amount of energy u have spent. you can generate electricity with dynamo, but at what cost?

Answer 5

Actually. losses occurrence takes place, like friction loss, eddy current loss and many more losses, due to which the energy spend cannot be equally utilized . And as for Ac current u cannot store it. while DC current mat be stored.

Answer 6

But scientists have to think about it.