Transition of Relays for Communication and Development to the Relays for Control Systems

Takeshi AOKI  

C - Abstracts of IEICE TRANSACTIONS on Electronics (Japanese Edition)   Vol.J100-C   No.10   pp.437-443
Publication Date: 2017/10/01
Online ISSN: 1881-0217
Type of Manuscript: INVITED PAPER (Special Section on IEICE 100th-Anniversary Historical Review on Electronics for Communication)
contacts for speech path switches,  contact surface films,  contact resistance failures,  relays for communication systems,  relays for control systems,  electronics technology,  

Full Text(in Japanese): FreePDF(1.5MB)

Contacts for electromechanical relays were applied to key components of telephone exchange systems, for which high reliability is required. Formation of contact films was dominant to the reliability. However, formation of contact films changed with the environment due to industry restructuring, so, the measure for contact films had distressed the researcher and engineers. In 1970s, when the electronics technologies had made progress rapidly and waves of digitalization reached communication systems, the exchange systems were digitized in one sitting. In this time, large drop of demand of relays were worried. However, electromechanical relays sifted key systems from communication systems to control systems such as industrial machines, automobiles, household appliances, taking the advantage that the relays have merits for applications to systems of higher voltage and larger current area. In this paper, at first, transition of contacts for the exchange systems and new development to the control systems are described, next, proposition of R&D and qualities of researchers and developers are described through them.