DC motor as tidal turbine model generator

Hello Folks!
I am currently working on a tidal turbine model, and need to have enough electricity generated to power a few LED's.
I presume to get about 10rpm in the hydraulics lab, and need a few watts to power the LED's. I was wondering, as small DC motors are specified as motors and not generators, how I could find the right one for this application or i anyone had a suggestion for what to use.
Many thanks!
Jonah
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Perhaps those that are fitted to wind-up torches. They are cheap enough these days to buy and dismantle. Then you've also a source of high-brightness LEDs
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Geek wrote:

You are going to struggle to get enough volts with 10 rpm. Some sort of gearing to increase the speed will help a lot but do you have enough mechanical power. Any permanent magnet (model) motor will work as a generator LEDs don't need watts! a few volts and low 10s of mA is plenty per led say 50mW Bob
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On Thu, 23 Jul 2009 10:06:13 -0700 (PDT), "Jonah Tremblay - VP Finance, First

I doubt that you'd find anything that would output much at that speed, and a geared-up version would take too much to drive it.
What sort of diameter turbine are you looking at using?
Peter -- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk http://www.oldengine.org/members/diesel http://www.stationary-engine.co.uk http://www.oldengine.co.uk
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On Jul 23, 6:06pm, "Jonah Tremblay - VP Finance, First Year Rep"

Where do you get the 10 rpm from ....have you been looking at those huge wind turbines ............that's a different scale and a different ball game .
Those little computer fans .......if the fluid is funnelled to-wards them..venturi fashion, can be made to turn very fast ..a current of 10 mph can be multiplied ten fold through a venturi..maybe more
forget the two bladed props idea
then you'll get the power.
all the best.markj
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The 10 rpms was just the lowest average of the information I could muster on the internet... I have to work with either one of these models, but the venturi system does sound intriguing... As of right now the flume water depth is 34 cm and the speed is 0.24m/s..
Thanks!
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