What I want is to generate electricity out from a 2Kw generator alternator and driven by a 800watts AC motor or any AC motor which is much smaller in electricity consumption. I am not thinking of a perpetual machine but to minimize my electric consumption. The AC motor will be connected to the power grid to drive the 2Kw generator alternator.. is this possible? Thanks ahead.
Yes, but you can only load the generator with something less than 800 watts. Remember, there is no such thing as a free lunch, and you can't get power for nothing...well actually you (sort of) can with a solar collector.
But you are thinking of a perpetual machine . You attempt would lead to a negative result, where you pay more for the losses.
That type of connection is not going to minimize your electric consumption. It's going to just increase your bill. 800 watt-hours in --> less than 800 watt-hours out. That's a law of physics, and there's no way around it. You're just going to lose energy as heat, in the motor and generator. The 2 KW generator just will not be operated fast enough to get even 800 watts out. You would be lucky to get even 400 watts out of a hook-up like that, with 400 watts going up as extra heat.
You can operate a 2kW generator with an 800W motor, but your total output will be exactly 800W. However, about 10% of that 800W output will be heat, so the useable, electrical output will be about 720W. Often people will spin the shaft of a generator by hand and think that, since it takes relatively little torque to make the shaft turn, that a smaller motor could spin the generator at its rated speed. Since the generator's electrical power rating is higher than the motors, it will then put out more energy than is required to power the motor. The small motor can indeed spin the generator to its rated rpm. But, when an electrical load is connected to the generator, equivalent to the generator's rating, the torque suddenly increases and will drag the motor to a stop, or to a much slower speed, reducing the generator's electrical power output below that which the motor draws.
