Ametek DC motor wind turbine
I've been working on this wind generator for quite a long time to supplement my 36w of solar... The frame is made in a 'Y' shape, welded out of box section: I used an arbor off ebay to attach the blades to the hub, this screws onto the shaft, clamping onto the back piece of plywood tightly. The whole assembly sits on top of a 10' piece of standard 48mm(about 2") scaffolding pole, it is below roof level but its the best that can be done in the city with not much space. The scaffold pole attaches to the washing line pole, which already has about 2' of concrete underneath. The guy wires are attached to a 3 way 'guy ring' that I also got off ebay, this clamps on tightly to the pole and works well: The cable goes down the middle of the tower pole and exits at the bottom and goes into PVC conduit. On most sites except very turbulant sites, there shouldn't be much twisting of the power cable as the wind turbine will rarely make a 360 degree turn, if you're worried about this then a plug and socket can be put at the bottom of the tower to be unplugged and untwisted when needed. I've used low temperature 'arctic' power cable, after coming down the tower, this then goes over the garden in a well-hidden trench, up the wall into my loft room through the eaves to my battery bank.
I do live in the city so I'm quite limited sizewise, however there is good wind.
The generator itself is a large DC motor from old reel to reel tape drives from the 1980's, these can generate 50-100w of power easily. They're pretty easily available off ebay or on the internet made by a company called 'ametek', they aren't made any more but widely available surplus; I used the 38v model with this one; the 30v model is also good. See here for more information on the various types and how well they perform. They put out approximately 12v at 300rpm, so a 4ft diameter propeller was used. These generators output DC power, but they need a diode inline with the positive line to stop them turning into a motor and spinning the blades.
The blades are made out of wood to the measurements from Hugh Piggott's book (available here). A plywood hub was used for this, but a metal hub would probably be better and stronger.
I balanced these with lead flashing screwed on, the blades are mounted on a bearing and weight is added opposite to the blade pointing downwards until the blade set is balanced. Another way is to hang the whole set on a small piece of string or fishing wire etc held exactly in the centre, then adding weights until they are perfectly level:
The motor is mounted to the mount using 5mm threaded rod bent round to act as U-bolts.
The wires themselves are 3.2mm steel cable that terminate with thimbles+wire rope clamps, the ground anchors are the 'screw in' auger type, came in a set of three for trampolines, each about 2' long with a flat plate 'screw' at the end, these hold in tightly and don't budge. Guy wires take most of the stress from the wind turbine and stop any sidewards movement so they are important to get tight and strong, but don't overtighten the cables. Turnbuckles are on this end to tension the cable:
The whole thing assembled and in the air:
This will make up to about 100w of power with a cost of £50-150.