TABLE OF CONTENTS Windmills and bicycles are relatively old mechanical systems, invented several centuries ago. They are still in vogue due to the simple and elegant principles involved in their synthesis and application. Both have gone through lots of innovation. In this chapter, we look at the materials being selected and used for various components in these basic systems.
The windmill works the opposite way of a normal fan. It is used to generate power to carry out mechanical tasks or to produce electricity from the wind power. The kinetic energy of the wind turns the blades attached to a shaft, which in turn rotates to produce mechanical power or electricity. In olden times, the windmills were used to grind grains or to move and pump water. The current trend is to use a number of them in a farm to generate giga-watts of electrical power. Figures 27.1 and 27.4 show modern wind turbines on such a wind energy farm.
Just like the fan, the windmill is a relatively simple mechanical system. Figures 27.2 and 27.3 show the basic system with components identified. The important components are: the blades that are moved by the wind, the hub...
