Horizontal Axis Windmill.
Horizontal Axis Windmill Features Low cost, effective teaching. Genuine commercial product, modified. Variable number of blades. Variable blade angle. Determination of power output and efficiency. Requires source of wind. Three year warranty. Range of Experiments To determine the electrical power output and stalling point for a windmill over a range of Wind speed Blade Angle Number of Blades To investigate the effect of blade stall v. power output To determine the electrical and mechanical efficiencies of the windmill for the same variables as in (1). Description The windmill is a modified version of a small commercial machine used for yachts and country cottages. It has six plastic aerofoil shaped blades mounted in a hollow hub which contains a set of permanent magnets and a looped conductive winding. When the mill rotates, an alternating voltage is generated. Windings are mounted on a disc, which is fixed to a shaft running in bearings. This shaft is restrained by a phosphor bronze spring, strain gauged to measure torque. An inductive transducer is used to measure rotor speed. From these results the mechanical power can be established. Electrical power output is measured in terms of the output voltage across a variable load. The six blades are mounted in adjustable bosses so that their pitch can be altered. Blades can also be removed to assess the effect of blade solidity. A source of wind is required. This can be provided by the Wind Machine. This equipment is part of a range designed to both demonstrate and experimentally confirm basic engineering principles. Great care has been given to each item so as to provide wide experimental scope without unduly complicating or compromising the design. Each piece of apparatus is self-contained and compact. Setting up time is minimal, and all measurements are made with the simplest possible instrumentation, so that the student involvement is purely with the engineering principles being taught. A complete instruction manual is provided describing the apparatus, its application, experimental procedure and typical test results