At present, domestic overvoltage and undervoltage protection devices are mainly in the following forms.

1. Voltage protector for single electrical appliance. The main protectors of the tired protector are air conditioners and fridges. It can automatically protect when the voltage is too low, too high or the power is cut off for a short time. When the voltage is always unstable, it will shorten the life of air conditioners and refrigerators, and even damage the compressors or motors they use. This kind of protector input adopts plug, the output uses socket, the output current is generally less than or equal to 10A.

2. Miniature circuit breaker with additional undervoltage and over voltage tripping machine. The utility model has the advantages of easy implementation, low consumption and convenient installation. But the disadvantage of this scheme is that it reduces the continuity of power supply, and the power grid can not be automatically closed after the protection action is restored to normal, so it needs manual operation.

3. Full automatic voltage protector. It is used to automatically disconnect the power supply when the voltage in the circuit exceeds the allowable limit of the load, so as to protect the electrical equipment from damage caused by overvoltage and undervoltage. When the power supply voltage returns to normal, the power is automatically connected after the set delay is set. Most of them are realized by simple analog circuits. The circuit structure is simple and the relay is released when working normally. Due to the long-term operation of the relay when working normally, the power consumption is high. In addition, analog electrical apparatus has low voltage sampling accuracy, large delay time error and time-consuming adjustment.

In view of the above situation, it is necessary to develop and design the overvoltage and undervoltage protection devices with high voltage sampling accuracy, small delay time error, simple adjustment, energy saving and environmental protection.


FAQ for overvoltage and undervoltage protection devices

1. What is the function of the voltage protector? What is the role?
It is mainly used for low voltage protection, such as motors, too low voltage to start.

2. What is the principle of over voltage protector?
The power overvoltage and undervoltage protection devices measures the power supply voltage, sets the voltage range in the relay, and outputs the node. When the voltage is lower than the given value and higher than the given value, the relay acts to cut off the power supply circuit.

3. What is the reason that the voltage protection devices are cut off without any reason?
(1) failure of under voltage protector or improper settings of protector undervoltage protection.
(2) Can measure the voltage at the access terminal, if the voltage is normal, then the product failure, or the product used to break the relay suction voltage can not reach, can not suck, can try the true RMS measurement, error less than 1% of the product.

4. Can voltage protection devices be replaced by circuit breakers?
Of course not, because the contents of the two are different. The main function of the circuit breaker is to break the short-circuit current. When a short-circuit fault occurs, the circuit breaker will trip the protection equipment. The function of under voltage protector is to trip when the system voltage is below the set value.

5. Electrical clearance and creepage distance of voltage protection devices
The minimum electrical clearance and creepage distance of the circuit breaker are related to the voltage, the dirty degree of the electrical surface and the shape of the charged body. The minimum electrical clearance and creepage distance of the circuit breaker are at a given rated voltage, so the minimum electrical clearance and creepage distance should be at the same voltage. It should be the same.