GB240442A - An improved method of and means for synchronizing rotating bodies - Google Patents

Abstract

240,442. Lorenz Akt.-Ges., C. Sept. 25, 1924, [Convention date]. Synchronous movements.-Two rotating members, e.g. in a telegraphy or television system, are synchronized by transmitting an alternating current having a frequency corresponding to the speed of the member at the transmitting station, and having a definite phase relation thereto, to a cummutator driven by the member at the receiving station, applying the output current from the commutator to the grid-filament circuit of a thermionic valve, and using the plate current to apply speed corrections to the member at the receiving station. Fig. 1 shows a commutator C driven by a motor R which is to be synchronized with a generator S at the other station by transmitting from the generator to the commutator over the line L a current having a definite frequency and phase in relation to the speed and phase of the generator. The commutation is arranged to be effected at the maximum values of the current when the speed and phase of the motor R corresponds with those of the generator S. Under these conditions the output current from the commutator remains zero until a loss of synchronism occurs. This output current is applied through a transformer Tr to the gridfilament circuit of a thermionic valve T, and the resulting current from terminals e, f in the plate circuit is utilized to correct the speed of the motor, e.g. by applying it to a field coil of the motor or to the coil of an eddy-current brake. Fig. 4 shows, an arrangement in which a more accurate synchronism is obtained by the use of a second valve to eliminate hunting. The motor R drives the commutator C and a member V adapted to be braked by eddy-current action upon energizing coils c1 or c2. The commutated received current is applied to the grid-filament circuit of a valve V, of which the plate circuit includes the braking, coil c, as in the arrangement of Fig. 1. This plate circuit includes also the primary of a transformer Tr, the secondary being connected as shown to the grid-filament circuit of a second valve T2 of which the plate circuit includes the braking coil c2. The subjectmatter claimed in Specification 234,529 is disclaimed. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the application of the invention to the electric control of clocks. This subject-matter does not appear in the Specification as accepted.