Development, Testing, and Implementation of a Gas Turbine Starting Clutch With Manual Turning Feature for U.S. Navy Ships

Most gas turbine generators rely on an automatic-engaging, free-wheel clutch to connect a starting motor to accelerate the gas turbine generator from zero to some intermediate speed to enable ignition and then provide torque assistance to a higher speed until the gas turbine is self-sustaining. The U.S. Navy has used various designs of starter motors and clutches for its gas turbine fleet. In addition, there has been a requirement to periodically borescope each gas turbine, which has necessitated removal of the starting system and clutch assembly in each instance. This paper examines the U.S. Navy experience with starting clutches and provides details of the development and testing of a synchronous-self-shifting clutch with an additional, stationary, manual turning feature to provide very slow and precise gas turbine rotor rotation for borescope purposes. This paper also gives details of the installation of the first two prototype clutches on the USS Ramage, DDG 61, operating experience for approximately four years, and possible future installations of this type of clutch in U.S. Navy gas turbine generator sets.