The development of variable-speed high-power drives for large wind tunnels

The paper outlines the power requirements of large wind tunnels, with particular reference to the compressor driving plant for high-speed and multi-purpose tunnels. After briefly reviewing available driving methods, with examples of typical installations on existing tunnels, the needs of a particular research establishment are described. There two or more large wind tunnels are being built, each requiring high powers at variable speed and using synchronous motors for the main driving power. To meet these requirements, the case for a system consisting of a fixed-frequency supply from the Grid and a variable-frequency supply generated on site is discussed.