An automatic relay is an electrically operated switch that can automatically control an electrical circuit based on predetermined conditions, such as current, voltage, temperature, or time. When the relay detects an abnormal or predefined signal, it operates its contacts to either open or close, thereby controlling the circuit. The main purpose of an automatic relay is to ensure the safe operation of electrical systems by protecting them from overloads, faults, and abnormal conditions.

    Working Principle of an Automatic Relay

    The basic working principle of an automatic relay revolves around the electromagnetic or electronic mechanisms that control its operation. When a relay is powered, an electrical current passes through its coil, generating a magnetic field. This magnetic field attracts or repels a contact arm, causing the contacts to either close or open. In some cases, the relay may use thermal or electronic sensors to detect specific conditions like overcurrent or overtemperature, triggering the relay to act accordingly.