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Advice needed - Desk fan / pedestal fan as wind turbine giving 5v Answered

i've seen a few ideas online but so far no clear instructions. I want to mount a fan outside, probably on a spinning head to face the wind, then run that current through smoothing capacitors and a step down convertor to give a stable 5v output (through a usb port). The problems I anticipate are 1. keeping the electrics of the fan dry (I was thinking of mounting it in a hood / tunnel to keep the rain off) 2. the spinning head and not having cables twisting and breaking (maybe i could use the oscilating head of the fan to do this?) 3. too much power coming in and damaging the capacitors / step down convertor. Has anyone attempted a similar project and / or have any advice on this please?

Discussions

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iceng

1 year ago

What makes you think you will have too much power and need to step down ?

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oragamiunicorniceng

Reply 1 year ago

as a desktop fan takes 240v to spin, I thought that in reverse, used as a turbine I would expect some hi spikes (in strong wind) of maybe 50v, that is pure guesswork, but that is my concern

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icengoragamiunicorn

Reply 1 year ago

Fans are shaded pole induction motors

https://en.wikipedia.org/wiki/Shaded-pole_motor

These fan motors have only one coil and no magnets to generate any electricity..

I just went out to my shop and videoed a drill spinning an induction motor and will probably publish the no output effort..

Even used an AC excitation capacitor to no avail !

GearMotor.jpegShaded_pole_motor.jpg
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oragamiunicorniceng

Reply 1 year ago

Thankyou for all your effort, any ideas as to what sort out motor could I use that is powerful enough to generate a reasonable amount of electricity and is scavengible?

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icengoragamiunicorn

Reply 1 year ago

Any PM (permanent magnet) motor or stepper motor they don't need additional components.. Then a bike generator and a car alternator are easy to get..

But what is a "reasonable amount of electricity" volts, current or watts ?

Alternator Slipring2.bmpDC motor.jpg12vGen.PNG
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Yonatan24oragamiunicorn

Reply 1 year ago

If you're afraid of spikes and can't solve it with capacitors (can't help you with that), perhaps you could add a bit of weight to the shaft of the motor somehow, so it will take it more time to speed up/slow down?

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oragamiunicornYonatan24

Reply 1 year ago

that's an interesting idea, essentially creating a flywheel. I think it would have to be a fairly precise fit and well balanced on the shaft. I was basically planning on using the existing mechanism of the fan, so I'm not sure where I would add in a flywheel. I suppose there is the option of adding weight to the outside of the fan blades, although I'd be worried about effecting the aerodynamics that make it spin

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Toga_Dan

1 year ago

try a low v fan. As iceng says, ac fans wont work as generators . 12v and 5v fans are on the market