General principles for relay selection

How can I choose the relay correctly? First, it is necessary to "know the known one", that is, first of all, the nature of the controlled loop, the characteristics of the controlled loop, and the requirements for the relay must be thoroughly investigated and thoroughly understood. Secondly, the various characteristics of the relay itself, the use conditions, technical parameters, structural process characteristics and specifications and models, etc., to achieve a comprehensive grasp and careful analysis; Second, in accordance with the "value engineering" principle, from the advanced and reasonable Sexuality, usability, and economy are all considered, and the relays are properly selected and used. The principle of correctly selecting a relay should be:
(1) The main technical performance of the relay, such as contact load, operating time parameters, mechanical and electrical life, etc., should meet the requirements of the whole system;
(2) The structural type of the relay (including the installation method) and the external dimensions should be suitable for the needs of the use conditions;
(3) Economically reasonable.