Wind Turbine in the Making
by Glyn Hudson
I turned up in the workshop on the first day, not sure what to expect. After an initial safety briefing I was put to work crafting one of the three turbine blades. This involved measuring, then cutting up a block of hardwood into a blade shaped block. My job was to create the taper and the initial twist of the blade. This was done using a chisel and a saw to remove excess wood, then using a draw knife for more precise wood removal. It wasn’t long before the wood looked less like a block and more like a part of a wind turbine. The last step was to clamp all three blades together then plane and sand them simultaneously to ensure consistency. It was very rewarding to see the blade taking shape as the day went on.
Later I had an opportunity to try my hand at arc welding; something which was totally new to me. It was not easy to pick up. I found I did not possess the godlike precision in my wrist that is required to get the ‘arc’ going. The ‘arc’ is electric current jumping or ‘arcing’ from the welding rod onto the metal. To create it the welding rod must be held just above the surface of the metal, but not touching it. Due to the arc being incredibly bright a dark eye shield must be used. This makes it very awkward to see what you’re doing, as the eye shield is opaque before the arc is created. After quite a few attempts I proudly managed a couple of successful welds.
Due to other commitments I sadly had to miss the next few days of building. When I returned on the final day I was very impressed at the progress the team had made. The blades had been given an aerofoil and had been drilled and varnished. The base and guy lines were almost finished and Trystan had nearly finished the charge controller.
I helped Trystan solve some problems with the charge controller; an electrical circuit which stops the batteries being over charged or undercharged. It works by ‘stepping in’ more batteries into the charging circuit if the wind speed increases and the turbine produces more power. In the end it was decided not to use the charge control unit until we could get hold of some more powerful relays because of the high currents the circuit would have to deal with. I helped assemble the blades and wire up the coils. Sadly due to having to work that evening I missed erecting the wind turbine. Later I met up with the elated team in the local pub and heard the good news. I was told that the wind turbine produced too much power to safely charge the two batteries, more batteries would be needed. I also heard all about the after party which took place on the mountain to music powered by the wind turbine!
The team were understandably proud of their efforts, most if not everyone had learnt new skills and developed excellent team working skills. I recommend that everyone should build at least one wind turbine in their life time!