Fecha de publicación: 06/11/1913 Fuente: WIPO "pollen" 9223. Pollen, A. H., and Isherwood, H. April 19. Synchronous movements.-The speed of an electric motor is governed by that of a shaft 2 which is rotated e.g. by a clock. The motor shaft 3 is geared down so as to drive a rheostat 8 synchronously with the clock shaft which carries an arm 7 resting on the rheostat contacts. The motor current is fed through the rheostat by means of slip rings 9, 10 and is varied to give a constant armature speed by the variation in resistance as the speeds of the rheostat and arm vary.