DC Motor asd Gen?

[RobT]

I just bought a DC motor, 300w output, 4 brush, 4 magnet 16 pole, 24vdc,16.4amp @ 2650rpm. I have no idea as to whether I can use this as a small Alternator for a windturbine.  If so, what mods do I have to make?  Any idea of the output?  I know just enough to be dangerous about these things, so thought I'd better get some advice!

Thanks! RobT

[iFred]

Put a voltmeter on the outputs set on DC and measure the output at different RPM's, make a basic two column spreadsheet...then report back with the data.

Rpm's =  Volts DC

Rpm's =  Volts DC

Rpm's =  Volts DC

Rpm's =  Volts DC

Rpm's =  Volts DC

etc..

[Flux]

Rob

It will cut in on a 12 volt system at about 1500 rpm, it is too fast.

If you really think it is worth it you may be able to rewind it with more turns if you can re connect to the commutator.

Flux

[drdongle]

Actually it will have to run faster than that to charge consider that nominal auto charge voltage is 13.8 and then you have .6 for the blocking diode.

It'll have to run more like 1800 RPM.

Carpe Vigor

Dr.D

[Opera House]

I just found  a standard 1/4 hp 90V dc motor commonly used to run variable speed conveyors etc.  Only a two brush, but I can easily spin it by hand and get 7-8 volts.  This is a 1725 rpm motor, 44V/1000 rpm with a resistance of 2.8 ohms.  This should easily start charging at about 275 rpm. A littl bulky and not great bearings, but these are common as dirt and should make a good generator.

[DanB]

generally - under no load, I think that voltage is directly related to rpm, so you really need only test at one speed to get the volt/rpm ratio.

but in this case Im doubtful it would be a very good choice.  Usually - with DC motors, under no load, we'd expect rated voltage out at the rated rpm, or close to it.  So.. if this motor is rated 24 volts at about 2000 rpm, I would expect that youd see about 24 volts out.. at about 2000 rpm, or 12 volts at about half that speed.  Probably not a very good choice for a wind turbine.

[drdongle]

These are commonly referred to as "conveyor" motors and is a much better choice than the 24V unit.

Carpe Vigor

Dr.D

[Parameter]

Might it not be possible to just put the windings in serie with diodes instead? I was wondering about those too but resistance will be up the roof I guess.

thanks for the conveyor motor tip.

Para

[RobT]

Thanks everyone, for your helpful comments. It's nice to get the benefit of a multitude of thoughts! In time, I hope I can give something back in the way of helpful thoughts.

Rob T