A great little article from LSG Forum member "Pogster"
I have always wanted to generate my own electricity from the brook that runs along the perimeter of my property. About three years ago I installed a temporary wheel to see if a larger one would be viable.
The demo wheel was made out of some old ply and some Indian stone pallet wood and for a generator I used an old AMETEK dc tape drive motor. To gear it up I used mini-moto chain and sprocket - 70 tooth on Wheel and 9 tooth on the motor. Total cost about £30.
Here's a video of the old wheel.
It generated about 25W at full chat - mainly because of the restrictions of the AMETEC motor and the size of the wheel it ran for about 1 year and gave me a good grounding for producing the large wheel.
First off I needed to dam the brook to a higher level so the water could enter the wheel at about midway "breast shot". I did this by waiting until the height of summer and using a sump pump from work to bypass the water to allow the cement to set.
The wheel is made from two sheets of 13mm marine ply from the local builders merchant. The disks are cut from one peice and the paddles are cut from the other. 12 paddles in total making the wheel easier to mark out.
Here are some construction pictures:
Once the wheel was finished I gave it a couple of coats of thompsons waterseal to try and prolong it's life. I then set about making and installing the supporting frame. This was made from some 3"x2" Oak that I had been given as surplus and was bolted together using M10 SS coach bolts. The Oak was extremly hard and required pre-drilling on all fixings. The Frame was then bolted directly to the stream bed rock base ready to accept the wheel.
The wheel was then lowered onto the frame. I did this by throwing a polyprop. rope over a large branch, tying it off to the fence and then kicking the wheel of the edge. Thankfully the branch held and I sort of lowered/dropped the wheel into the stream.
WIth the wheel in place the next step was to sort out the gearing and a Generator. I initially used minimoto gears but the small sprocket kept stripping itself so I purchased a 3/8th's inch chain(s) and sprockets from a bearing suppliers. The generator is a Windblue Power Permanent Magnet Generator. It is designed to give 12V at 150rpm and is basically a converted car alternator. A normal alternator would give 12V at 3000rpm. The PMG came directly from the USA for £135 inc. Postage. As the wheel spins much more slowly due to it's size I had to use a two stage gearing system as can be seen in the following photos.
I have also added a 10mm steel cable to the main spline that is then bolted to the bed rock using a 1ft long anchor bolt, this should stop it being carried away should the brook flood and the wheel break free. A problem that could cause flooding to my next door neighbours property so I'm quite keen to avoid.
The Wheel feeds 4x55AH batteries (AGM deep cycle type) that I got for free from work - Brand New! These are located in my home office and run / charges two laptops almost continually. I have just acquired 2 x 110Ah military spec Hawker batteries that I intend to use to power by garage and home lighting from also. The wheel feed will be split between the two systems.
That's it! the wheel has been in use for over a year now and provides typically 50W continuously and peaks at about 500W. During the so called summer it did stop altogether a couple of times for no more than a couple of days due to lack of water in the stream. It's also been completely covered during a flood - Quite worrying!
Heres a couple more Pics:
(Yes it is a mains powered welder! - Don't try this at home kids )