What rpm must a 24v dc generator turn to produce 24v?

[aidrenegade]

I'm working on a little science project and was wondering if anyone knows how fast a 24v dc generator (or motor) must turn to produce 24v? I think a 12v version might be about 80rpm. I have yet to test if my little idea can actually drive the generator but need a rough idea to figure out the cog sizes required.

 

[(*steve*)]

It depends on the generator and the load.

There is no simple rule of thumb.

 

[TBennettcc]

Try to attach to a variable speed drill and measure the voltage output? Or another motor with a known RPM?

 

[aidrenegade]

Thanks for responding!

Thanks *'steve*', I think I should assume no electrical power load to start, just the energy to turn the generator. I have absolutely no experience with motors, so please feel free to elaborate if you can.

Thanks 'TBennettcc', I thought of using a drill but that still wouldn't let me know how fast the rpm was. I don't have a way to measure the rpm so I'll have to use the' hit & miss' trials technique.

Anyone, please add any ideas or thoughts. Bearing in mind my lack of experience in this area, there is no such thing as a dumb idea to me. Think I'll get hold of a motor first, or dig deeper into those google results...

 

[KJ6EAD]

If you have a multimeter with the ability to measure frequency, you can rig a small magnet on the shaft and use a small inductor to measure the rotations per second then multiply by 60 to get RPM.

 

[TBennettcc]

...or, to further the answer given by KJ6EAD, use an oscilloscope to look at the waveform the spinning magnet generates in the inductor? Know anybody who has one (and knows how to use it?)

I know it's a long shot, but I figured I'd throw my $0.02 in anyways.

 

[tedstruk]

I'm working on a little science project and was wondering if anyone knows how fast a 24v dc generator (or motor) must turn to produce 24v? I think a 12v version might be about 80rpm. I have yet to test if my little idea can actually drive the generator but need a rough idea to figure out the cog sizes required.

The data you want is about power, not motor rpms!
It must turn a minimum of 1amp per hour, to charge. ie. amperehour?

All generators have their own specs..