Below is a list of Rotary Compressor manufacturers from Milwaukee, Wisconsin. A rotary compressor reduces the volume of air by compressing it between intermeshing, counter-rotating components that force the air into a tank. Rotary compressors are constructed of stainless steel, aluminum or cast iron. For industrial or extreme conditions, the metals may be heavy duty grade. Compressors can be gas powered or electric; mini or portable compressors often run on batteries