Working principle of overvoltage and undervoltage protector

Overvoltage and undervoltage protector is a multifunctional protection instrument, mainly used for monitoring and protecting three-phase three-wire power supply system or three-phase electrical equipment. It integrates three-phase voltage display, overvoltage protection, undervoltage protection, phase loss protection, three-phase voltage imbalance protection, phase sequence protection in one. The working principle of the overvoltage and undervoltage protector is mainly concerned with providing relay protection for the three-phase input power supply, such as the voltage is too high, the voltage is too low, the phase is out of phase (reverse phase sequence), and the three-phase voltage is not balanced. When the line voltage is reduced to the critical voltage, the protective electrical action is called undervoltage protection, and its task is mainly to prevent the equipment from burning due to overload. In contrast, when the voltage exceeds the set value, overvoltage protection is activated to protect the device from excessive voltage damage. Over and under voltage protector through electronic circuits such as high voltage comparator, low voltage comparator, voltage regulator and output circuit, automatically close the switching device for the contactor, quickly cut off or turn on the power, to avoid abnormal voltage adverse effects on household appliances or lines, when the voltage returns to normal, the undervoltage protector will automatically turn on the circuit within the specified time