Donald Mainland
17th December 2017, 11:08
To avoid occasional violent mast oscillations with my 6 kw Eoltec on a 12m mast, I have attached three guy wires, at 120 degrees in the ground plane and about 26 degrees to the mast, from just below the blades' lowest point to buried concrete blocks – 700 x 400x 300 mm, with re-enforcing rods.
The top end of a 10 mm 7x7 galvanised wire rope with thimbles at each end is attached via a stainless steel shackle to a lug on a stainless steel mast clamp. The bottom end is attached to a 102 mm 280 N/mm compression spring to a stainless steel turnbuckle to a chain embedded in the concrete. The spring is encased in a stainless housing pulling from opposite ends to convert it to an extension action. The turnbuckle allows for easy disconnection and setting of standing tension.
I am acutely aware that a few photos and diagrams would immediately clarify the above but I want to keep this article to a manageable length.
We recently had a gale with gusts of 90 mph. Normally I would have stopped the turbine for such an event, but this time I left the turbine running and the mast hardly moved. I would certainly advise against not using springs as violent jerks would not be smoothly absorbed.
I don’t know why only a few installations here have encountered this mast oscillation problem, but, touch wood, mine is now secure.
The top end of a 10 mm 7x7 galvanised wire rope with thimbles at each end is attached via a stainless steel shackle to a lug on a stainless steel mast clamp. The bottom end is attached to a 102 mm 280 N/mm compression spring to a stainless steel turnbuckle to a chain embedded in the concrete. The spring is encased in a stainless housing pulling from opposite ends to convert it to an extension action. The turnbuckle allows for easy disconnection and setting of standing tension.
I am acutely aware that a few photos and diagrams would immediately clarify the above but I want to keep this article to a manageable length.
We recently had a gale with gusts of 90 mph. Normally I would have stopped the turbine for such an event, but this time I left the turbine running and the mast hardly moved. I would certainly advise against not using springs as violent jerks would not be smoothly absorbed.
I don’t know why only a few installations here have encountered this mast oscillation problem, but, touch wood, mine is now secure.