Limitation of large excursions

Some limitation on teeter excursions has to be provided, if only to prevent collision between the blade and the tower. If the teeter hinge is located close to the axis of the blades, with the low-speed shaft passing through an aperture in the wall of the hub shell (see Figure 6.6), then the maximum teeter excursion is governed by the size of the aperture.

The teeter response to deterministic and stochastic loads is considered in Section 5.8.8. Although it is evident that a permitted teeter angle range of the order of ±5° will accommodate the vast majority of teeter excursions during normal operation, it is usually impracticable to accommodate the largest that can occur. Hence, in order to minimize the occurrence of metal-to-metal impacts on the teeter end stops, buffers incorporating spring and/or damping elements normally have to be fitted. These also perform an important role in limiting the much larger teeter excursions that would otherwise arise during start-up and shut-down, when the centrifugal restoring moment is reduced.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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