Speed Control of Electric Motors for Deck Machineries and Dredgers

Abstract

Recently, the author invented a new speed control method for electric A.C. motors called "Shibata Reducer". This method of speed control can be carried out by using wound rotor type induction motors and a D.C. motor generator. The original type of "Shibata Reducer" was derived from Scherbius system which consists of an induction motor, rectifiers and an auxiliary motor generator. We can find wide application of Shibata Reducer in industrial circles, and especially in vessels its splendid applications for deck machineries, i.e., for winches, windlass and so on. This method can also used in dredgers for the control of cutter motors, main pumps and swing winches. I believe that "Shibata Reducer" will be used for deck machineries of almost all vessels and dredgers of the world in near future. The valuable application of "Shibata Reducer" is in using a common motor generator for plural induction motors.