GB191313A - Improvements in and relating to synchronous motors for the electric drive of clockworks - Google Patents

Abstract

191,313. Michl, R. March 9, 1922. Electric clocks.-A synchronous electric motor for driving clockwork from alternating-current mains comprises a rotor having soft iron segments c<1>, Figs. 1 and 2, rotating in front of the poles N, S of a permanent magnet b and one pole e<1> of an alternating-current electromagnet f, the movement being transmitted to the clockwork h by means of gearing, for example, worm gearing g. In a modification, Figs. 3 and 4, two alternating-current electromagnets e are employed with two rows of segments c<2> and an electromagnet b of constant polarity having pole-shoes b<2> extending to the faces of each rotor. In another construction, shown in Figs. 9 and 10, the rotor is in the form of a segmental disc c and the poleshoes b<3> of the permanent magnet b alternate with the pole-shoes e<1>, e<2> of the alternating-current magnet e. The pole-shoe e<2> is connected to the top of the core e by the bow i, and the permanent magnet b is insulated from the electromagnet and supported by means of the plates k and screws l. To start the motor, a hand-operated toothed segment n is turned, thus tensioning the spring o, which on the release of the handle returns the segment n and drives a cog-wheel m mounted on the shaft d of the rotor c.