Over and under voltage protector is a protective device used in power systems to protect circuits and electrical equipment from over-voltage and under-voltage damage.
It usually consists of an over/under voltage detection unit, automatic closing switch device, and other electronic circuits.
When an over-voltage or under-voltage occurs in the circuit, the protector will immediately cut off the power to avoid damage to the circuit and electrical equipment. At the same time, when the voltage returns to normal,the protector will automatically connect the circuit within a specified time to ensure the normal operation of the circuit.