GB281597A - Improvements in, and connected with, electric signalling apparatus - Google Patents

Abstract

281,597. Hõttich, A., and Kuhn, F. Dec. 6, 1926, [Convention date]. Bell and audible signalling systems; signalling over power circuits.-Signal receivers' at a plurality of stations are operated over a direct current distribution system upon the reversal of the polarity of the mains in response to the actuation of a transmitting switch at any station. Bells q, q<1>, Fig. 2, at stations A, B are connected in series with rectifiers t, t' across the mains of a D.C. distribution system supplying lamps k. When a switch such as n is operated, a bell x at a central station is rung. An operator then reverses a switch u to change the polarity of the mains i<8>, i<9> and thereby allow the rectifiers t, t<1> to pass current and operate the bells. In a modification the bell x is replaced by a relay which reverses the polarity automatically. The Specification as open to inspection under Sect. 91 (3) (a) comprises also systems in which the rectifiers are omitted. Fig. 1 (Cancelled) shows a three wire distributing system wherein the bells q, q<1> at the different stations are connected between neutral and earth and the contacts j, j<3> of the transmitting switches n, n<1> are connected to the outers. When one or other of the switches is operated both bells are operated over a circuit including one or other of the generators z<1>, z<2>. If a fault develops on the outers, the bells are rung until they are short circuited by operation of one or other switch n, n<1> into engagement with contacts j<1>, j<2> which may be used to facilitate signalling while the fault exists. A similar system may be employed in combination with a four-wire three phase system of distribution. This subject-matter does not appear in the Specification as accepted.