What is a relay?
A relay is a small signal control electrical appliance, which uses signals such as current, voltage, time, speed, and temperature to connect and break small current circuits. It is widely used in the protection of motors or circuits and the automatic control of various production machinery. Since relays generally do not directly control the main circuit, but control the main circuit through contactors and other switching equipment, the relay has a small current-carrying capacity and does not require an arc extinguishing device. Relays have the advantages of small size, light weight, simple structure, etc., but the sensitivity and accuracy of their actions are relatively high. Commonly used are thermal relays, intermediate relays, speed relays, time relays and so on. (1) Thermal relay Thermal relay is a control electrical appliance for overload protection of motors and other electrical equipment.