It always amazes me how much free energy is around if you can access it, especially when the predominant ideology seems about scarcity and expense.
Cornwall, where I live, is particularly well-endowed with wind, which many people are rushing to exploit. Wind farms are quite divisive for local people as ‘bribes’ in terms of ‘community benefits’ (which are mostly just peanuts) tend to make people living within the shadow of the particular wind farm angry, and others, not so close, interested in the benefits. But enough of the politics.
I have always wanted to make my own windmills from scrap materials. I love the idea of making something out of nothing, but my science education wasn’t very good. I am more of a ‘creative’. I can do nuts and bolts, but volts and amps still leave me a bit puzzled and my electrical education continues with melting things and setting them on fire. Or not getting any results. But here I have made a mini windmill out of rubbish that generates a small voltage in an average wind.
I have seen examples of people using old electric motors and running them backwards – changing a motor into a generator – and wanted to start making these. From my understanding pretty much all motors will create some kind of voltage, but the ones that are best for small windmills need some seeking out. This is still technically beyond me but there is a great page on it here, that I am still working through.
One way to check that you are getting power, is to put the motor into a variable speed electric drill and measure the output with a voltmeter. In the first image I have got a tiny reading from a tiny motor, as you might expect. If you know the speed of the drill in rps then you can get some idea of how fast it needs to turn to get energy out. This is why slower motors like those used in treadmills, washing machines or overhead room fans seem to work quite well – many electric motors are made to turn faster than any wind turbine could.
Now I found a small electic motor that seemed to give quite a good reading and sought to connect it up with bits of rubbish that might make it go! It fitted exactly inside an old photographic film strip container and I made a hole for the hub. I had a flat plate of metal and cut out a turbine shape by drilling and cutting with metal shears. My model for this was the turbines seen on western movies that pump-up water from underground. I wanted metal to give it some momentum once it got going. I glued the propellor onto the hub with the aid of a rivet and some epoxy resin and tested it in the wind. It went round.
Back to my personal dump and I found the nozzle of a vacuum cleaner which was the same diameter as my film case. I wrapped the joint in a shimmy of aluminium and taped it up with insulation tape. I cut a piece of plastic from an old babies chair to complete the tail for wind alignment. I then drilled a hole though the nozzle and mounted the thing in between washers on an old bit of bicycle, which I stuck in the top of some leftover copper pipe.
Now to test it in the wind. I took it up to the top of the garden (we are on a hill) to try it out. Although it vibrated a bit in the wind – it showed up to 6 volts in an average wind. I mounted a bit of lead under the tail to balance it, which seemed to ease the shaking.
OK so its not much energy – but I guess (and it is a guess at this stage) that it might charge a six volt battery which could run a lighting system for a small space using LEDs. It cost nothing to make and it provides free energy. I think I might learn a bit more and make a bigger one!