GB251410A - Improvements relating to the control of electric switches operated by impulses - Google Patents

Abstract

251,410. Siemens Bros. & Co., Ltd., and Humphries, H. E. March 27, 1925. Automatic exchange systems. - In order to compensate for irregular incoming impulses at a selector of the Strowger type, the circuit of the vertical magnet VM is completed over an additional wiper D‹ which partakes of the vertical movement only and the terminals of which are grounded in turn. In the case of a first selector the grounding of the odd and even terminals of the wiper D<0> may be controlled by a pair of relays P, Q, Fig. 1, or by an auxiliary stepping switch, Fig. 3, which also serve to repeat ground in response to subsequent trains of impulses alternately over the a and b wires to the odd and even terminals of the wiper D<0> at a succeeding switch, Fig. 2. At the connector, a special rotary wiper may be provided for the purpose of operating the rotary magnet. In place of the wiper D‹, a mechanical change-over contact may be employed, operated at each step of the driving magnet. Specification 221,316 is referred to. First arrangement, Figs. 1, 2. When the trunk terminating in the incoming selector, Fig. 1, is seized, line relay A energizes over the b wire, and release relay V and dialling relay D operate in turn. At the first impulse, relay P (1) energizes over contact a3 and locks in series with relay Q (1), while the vertical magnet VM lifts the wipers one step over front contact p3 and wiper D‹. When contact a3 reopens, relay Q (1) energizes, being no longer short-circuited, and at the next impulse a circuit is closed through relays Q (2), P (2) in parallel. The windings of relay P are in opposition, so that it.releases and again connects up the vertical magnet VM at back contact p3. Relay Q relapses when contact a3 opens, and this cycle is repeated until the desired level is reached. Relay D falls back at the end of the impulse train and connects up the rotary magnet RM. In response to further trains of impulses, relays P, Q act as before, and relay D is energized, so that ground is connected alternately to the a and b wires at contact p4 to operate the succeeding switches, test relay T being energized. Answering relay Y upon energization sends back a supervisory signal at contact y1. At the second selector, Fig. 2, dialling relay D (2) energizes over the test wire, and incoming impulses over the a and b wires operate the vertical magnet VM over wiper D<0> and relay D (1). At the end of the impulse train, relay D relapses and connects up the relay magnet RM. Relay D is energized again upon operation of test relay T. Second arrangement, Fig. 3. At each impulse, back contact a3 closes a circuit for the magnet IR of an auxiliary switch of which wiper E‹ corresponds to contact p3, Fig, 1 and wiper F‹ corresponds to contact p4, Fig. 1. A restoring circuit for the switch is closed over wiper P<0> when relay D relapses at the end of each impulse train.