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Serving the Wind Industry since 1983 |
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The blades on Nordtank 150 kW showed play in the root section, and were literally loose. When polyester is crushed under high pressure it becomes black powder, so the failure was easily detected by the service crew. The fault was due to lack of respect for maintaining an even elasticity coefficient in the composite root. The original design was with steel bushings for each bolt. Hence the composite material was not carrying load by other means than the bonding to the bushings. We tested the e-modulus of the composite material and designed bushing that matched. The retrofit was done in 1988 and the blades are still in operation. Viking Windfarms 1 ltd. Mojave, California. |
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The original yaw system in a Nortank 150 kW was based on bronze lined sliders maintaining centering of the nacelle. These sliders deteriorated in a few months. Following a complete calculation of the forces in the yaw system, we designed rollers to replace the sliders. The engineering of the retrofit was done with maximum consideration of future low maintenance cost. |
