Patent GB-680891-A (GB)
Title: Improvements in or relating to a circuit arrangement for selector switches for communication installations
IPC: H01H67/16
Filed: 1951-07-12
Abstract: 680,891. Automatic exchange systems. SIEMENS & HALSKE AKT.-GES. July 12, 1951 [July 12, 1950], No. 16588/51. Addition to 680,959. Class 40 (iv). The parent Specification describes a vertical and rotary switch in which the wiper carriage is driven in both directions by a screw gear which is unidirectionally rotated by a stepby-step motor, rotation of the wiper carriage during vertical stepping being prevented by a guide member which is disengaged by means of an electromagnet to allow rotary stepping. According to the present invention, the disengaging magnet is energized after the completion of the vertical stepping and returns the step-by-step motor into operation by means of a special contact. As shown, the motor has two mutually perpendicular field coils M1, M2, which are energized alternately to produce step-by-step rotation of a Z-shaped armature (not shown). The motor shaft controls contacts m1, m2 which are closed alternately, and the motor is stopped by simultaneous energization of both field coils M1, M2. The disengaging magnet is designated by M3. Line finder, Fig. 1. Initiation of a call brings up line relay R, starting relay An common to all lines connected to the same bank of the finder, line finder starting relay R1, and relay Q which starts the motor by energizing field coil M2. The switch steps vertically until it reaches the level of the calling line, whereupon test relay P operates over vertical wiper dk, energizing both field coils M1, M2 to stop the switch and also bringing up relay PA to energize the disengaging magnet M3 which releases relay P, followed by PA. Field coil M1 is de-energized and the switch commences rotary stepping, closing rotary off-normal contact w. When the switch reaches the calling line, relays P, T operate in series over wiper c. The switch is stopped as before, starting relay An is released, relay PA extends the calling line to the next switching stage, relay D connects the starting circuit to the next line finder, and relay Q releases slowly to break the motor circuit. First group selector, Fig. 2. Relays A and C are operated on the engagement of the selector, and relay A responds to incoming dial impulses, bringing up relays E and V at its first release. The switch steps vertically, closing off-normal contact mo, under the control of relay A in response to the dial impulses. At the end of the digit, relay A remains operated and releases relay V to energize the disengaging magnet M3. This breaks the circuit for field coil M1, and the switch rotates to a free outlet where relay P1 operates over wiper cI, stopping the switch and extending the connection to the next stage. Relay E and magnet M3 fall off. Second group selector, Fig. 3. Engagement of the selector brings up relay C1, and relay Al responds to dial impulses, bringing up relay V1 at its first energization. Relay A1 controls the vertical stepping of the switch in accordance with the incoming dial impulses. At the end of the digit, relay A1 remains de-energized and relay V1 is released, breaking the motor circuit and energizing the disengaging magnet M3 in a circuit including off-normal contact mo. Relay V1 is re-operated and the switch rotates until it reaches a free outlet, whereupon test relay P2 operates over wiper cII to stop the switch and extend the connection. Magnet M3 and relay V1 are released, breaking the motor circuit.