Wire spring relay

A wire spring relay is a type of relay, that has springs made from drawn wires of phosphor bronze, rather than cut from flat sheet metal as in the flat spring relay. It provided greater reliability than other types of relays. Wire spring relays entered mass production in the early 1950s.

Wire spring relays were the most suitable relays for logic and computing functions. They were used extensively in markers, which were special purpose computers used to route calls in crossbar switch central offices.

Wire spring relays were primarily manufactured by the Western Electric Company for use by the Bell System in electromechanical telephone exchanges. The design was licensed for use around the world, and was commonplace in Japan.

Manufacturing of wire spring relays greatly declined in the late 20th century due to the introduction of digital electronic switching systems that used them in very small numbers.

Description

A wire spring relay has two major parts, the electromagnet and the contacts. The electromagnet can have a resistance of between 15 and 200 ohms, and is often designed to operate satisfactorily at a common telephony voltage, such as 24 or 48 volts.