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Make a Generator Answered

Alright so here is what I am looking for. I need a small generator that could fit inside of a box-fan. I've seen things about stepper motors and all but I need the absolute most simple generator you can come up with. I'm no electrician and I don't own a soldering iron, can anyone help?

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11010010110 (author)2008-10-06

I read somewhere that single phase AC (magnet-less) motors can make electricity too with an 'echo capacitor' connected. I plan trying that but dont know now if it works Try large diameter computer fans too (remove the electronics inside and connect diodes from 2 coils to + and - )

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olddawg (author)110100101102008-11-09

I would like to learn more of this 'echo capacitor'! I f you could pass along a link, it would be greatly appreciated.

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11010010110 (author)olddawg2008-11-09

i think its it

http://users.aber.ac.uk/iri/WIND/TECH/MISC/MotorsAsGenerators.html

there was something else with better explanation and graphics but i cant find it

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olddawg (author)110100101102008-11-09

Thank you. I took a quick look and I will return to figure it out. If you do ever find the other site, please do send it my way. I have a feeling this will be yet another discussion on this site! If it already has been, someone please send me that way....

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olddawg (author)2008-11-09

Check these people out.http://www.motorwavegroup.com/new/motorwind/index.html
I've been experimenting with low wind basic type wind turbines and I like what they are doing.
They are making what I concluded I needed to do.

They're pricing is still a bit high, but they are supposed to come out with a kit that should be affordable.

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ry25920 (author)2008-11-09

Uh, any dc motor can be a generator.

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Big Bwana (author)2008-06-17

What are you going to use this generator for ?? if it's for some thing like a science fair, a stepper motor and a few LED's are are the easiest way (( honestly if the motor has a plug in connector on it you don't even need a soldering iron )) So some more info would really help

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reedz (author)Big Bwana2008-06-17

I'm looking to make a portable wind generator out of it. It is for a huge summer project that I am working on. For now I just need something that could fit in a cage for a box fan and that could possibly charge a car battery.

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Big Bwana (author)reedz2008-06-17

The easyest way would be to find a small DC motor and a blocking diode and connect it to your fan, but the simplest is not aways the most efficient.. So I'll let you know what your looking at some thing that size your only going to get about 15 watts out of it and your going to need at least a +12 mph wind... and a car battery is about 70 Amp hour, so if it's dead your going to need like two to three days to charge it.... And what are you running of your battery, an electric fencer ? an inverter and TV ? a portable coleman cooler full of cold ones ??

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user

You forgot Betz limit, he can only get 7 watts out of a box fan at 12 mph and that's before losses.

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user

Theoretical maximum amount of wind speed that can be converted into energy.

betz limit

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user

Thanks for the link, that's really interesting.

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user

Sorry I was just doing a good guesstimate on a one of those large box fans So now he's at about a week to charge a dead battery (( not that you should ever run them down that low ))

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user

Good guesstimate. My math showed a max potential of 12 watts based on a radius of 25cm and a windspeed of 5 mps before Betz limit.

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reedz (author)Big Bwana2008-06-17

I just want it to run to a car battery as a proof of concept. I need to be able to make these cheaply and quickly (mass production eventually). There will be anywhere from 10 to 1000 working together depending on the application.

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Big Bwana (author)reedz2008-06-17

Cheaply and quickly, leading to mass production, then why not build them efficiently and quickly, we could talk about the cheaply later.. And use a stepper type motor, and change the blades so they are not a "box fan blade" and use turbine style blade... (( Your going to need a soldering iron ))

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reedz (author)Big Bwana2008-06-17

I want to use the box fan for the size and for the cage (to keep animals out) I only need one right now... as a demonstration. I will lead on to efficiency later on.

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Kiteman (author)2008-06-17

If you want DC, just run any DC motor backwards; use something to spin the rotor, and the motor will put out electricity instead of using it.

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reedz (author)Kiteman2008-06-17

Alright, that helps a little bit. #1 what would be "backwards?" #2 would it work efficiently with a wind turbine? #3 A DC motor from what object would you suggest? Thank you very much, I am glad to have recieved a response so quickly

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Tool Using Animal (author)reedz2008-06-17

Backwards, he just means you spin the motor, electricity comes out. DC motors generally suck in wind turbine applications, you need a high wattage low RPM motor, the usual choice is a treadmill motor.

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