Problems on Applications of Electromagnetic Gears

Abstract

A model having a capacity of 16, 000 ps was jointly developed by Japan Ships' Machinery Development Association and Kawasaki Heavy Industries Co. Ltd., during the term between April of 1972 and March of 1975. It was already described in several technical papers that sufficiently satisfied results which could make us believe that the device could be used practically on a ship was obtained by the tests. Owing to an emphasis of oil saving after the Oil Crisis of 1973, diesel engines have become the main current of propulsion engines of vessels. Particularly, a ship propulsion system of a propeller of low speed such as 36-65 rpm driven by a long stroke two cycle diesel engine of about 90 rpm having high reliability and high efficiency is holding the public eye. An electromagnetic gear can be thought most suitable for a power transmission of such a ship propulsion system.
Various technical characteristics of electromagnetic gears such as high efficiency, availability of clutch mechanism and reversibility of rotating direction could be confirmed by the tests. However, the first reason why electromagnetic gears can be considered to be widely used on board is that it was found that an electromagnetic gear can be manufactured by almost the same cost as that of a mechanical gear of the same capacity. We have been planning to use electromagnetic gears on several ships for these three years although fitting such electromagnetic gear on board has not been realized.
This paper introduces problems on applications of electromagnetic gears, reconsidering the results of manufacturing for trial and the tests.