electric generator question

[cameron sydenham]

Do you use just an electric motor to spin it (Gen)?
Are you trying OU Motor-Generator 

yes.

[khabe]

Then I dont understand at all ... why you do not measure what you spending and what getting. The only things you need are pair of clamp -and voltmeters ... not any needs to ask from anothers how the changing of rpm acts to power 
cheers

Hereby my bet:
P_out = P_in - (subtract) motor losses - (subtract) generator losses 

[mscoffman]

regular store ac generator.

here is where this is pointing.

if i can make my motor turn a this generator at its 3500 rpm, and the generator has load on it, ie accessories plugged into it, and i am using less than 5000 watts to run my motor....... we are in the green.

what i would like to know is if i can turn the generator at any rpm lower than 3500, can i deduce how much hp i am using..??

I don't believe you can because I don't think that particular generator was designed to run more than 10% away from correct RPM.
It certainly should not hurt to try as the generator probably won't be damaged. The 5KW is the *maximum* power the generator
could possibly put out. You may want a bank of incandesent lamps where the (100W) bulbs are indiviually switchable to act
as a dynamic load. To know the power output at an particular time you will *need* to calculate it based on the current voltage
times the current amperage output of the generator. A 100Watt bulb then is not 100Watts if the input voltage is half.

So you are going to *have* to be calculating the power output mathematically anyway at less then 100% voltage.

So for the test it would make more sense to run the input generator at 3500Rpm with no load. Then begin to switch in lamp loads
while trying to adjust your prime mover to supply 3500RPM. When you can no longer hold 3500RPM. then the lamp setting
is the maximum power you prime mover can supply.

You should look up CVT continous variable transmission. There is a CVT gearing unit that has a manual dial disk. As the prime
mover begins to slow down under load you could use the CVT to reestablish 3500 RPM output for the generator.

You should also google "syncronous generator" or "syncronous alternator" These are  genreators that idle as motors.
Then you use the CVT to "overrun" them. The more torque you put in the more you overrun the motor idle RPM
the more power goes out on the line. The line already needs to be powered by utility current. This is used for
wind generators and water generators.

:S:MarkSCoffman

[cameron sydenham]

yea, i have considered a cluthch or tranny style like you spoke about. as far as banking lights, we have that. i kind of figured that a generator can not be used as a rude dyno, all is fine though, as long as i can turn the generator at a certain rpm and put load, 5000 watts on it, and continue to turn at desired rpm, all is good.