B2B Portal Electronics

Relay fabrication has existed since the end of the 19th century, when the relay was invented. It is kind of an electrical switch that opens and closes – always under the control of another electrical circuit. The switch can be operated by an electromagnet or by various sets of contacts. Relays were in former times used for telephone switching or railway routing and crossing systems. Although there has been a tremendous high-tech revolution in the electronics sector in the past decades, and programmable devices have been manufactured, various relays are still used in certain applications and industrial environments. Relays have been proven to be reliable, long-living and simple components especially in rugged areas or in applications which require a high level of reliability, for example safety applications.

 

There are basically two types of relays: The electromechanical relay and the solid state relay. When going deeper, there are latching relays, reed relays, mercury-wetted relays, polarized relays as well as Buchholz relays, forced-guided contacts relays, solid-state relays and overload protection relays. A machine tool relay is typically standardized for the industrial control of machine tools. This type of relay was in former times a central factor for industrial automation of assembly lines in the automotive fabrication. A contactor relay is generally used for the switching of electric motors and lighting loads. Contacts for these relays, which are used to start motors, are commonly made of pure silver.

What tasks do relays fulfil? On the one hand, relays control high-voltage circuits with low-voltage signals. This type of relay can be found in several modems. But relays also control high-current circuits with low-currents signals, for example when used as an automobile starter. Protection relays are used to detect and isolate faults on transmission and distribution lines.

 

There are some general rules to keep in mind when using relays in your applications. Relays are highly sensitive to abuse. Therefore, users should avoid shocks such as dropping and hitting, as these shocks might decrease the performance of the device. Another general rule is to never remove the relay’s case. Relays need a dust and contamination free environment.

 

The relay device fabrication forces manufacturers to introduce and implement quality control and management processes. Lots of care is needed when packaging the sensitive devices. The international relay market benefits from standards, which are established, introduced and amended on a global basis. Uniform measures, quality criteria and regulations make components compatible and comparable.