An
auxiliary relay is a type of relay used in electrical control systems to perform supporting or secondary functions. Unlike primary relays, which are responsible for the main switching action in a system (e.g., turning on/off motors or circuits), auxiliary relays are used to assist with monitoring, controlling, or signaling secondary functions. They are typically used in
power distribution systems,
automation systems,
protection schemes, and
electrical circuits to enhance system performance, reliability, and protection.