Working Principle And Wiring Method Of Surge Protector
Surge protectors, also known as electrical surge protectors, effectively prevent damage to equipment caused by surges and transient voltages. The working principle of a surge protective device is primarily based on two core components: a varistor (MOV) and a gas discharge tube (GDT).
The Role of the Varistor (MOV)
The varistor is one of the key components of a surge protector. Its main function is to rapidly reduce its resistance when the voltage exceeds a predetermined threshold, thereby diverting the excessive voltage and protecting downstream electrical equipment. Because of the non-linear characteristics of the varistor, it exhibits high resistance under normal operating voltage. When the voltage rises to a certain level, the resistance drops rapidly, allowing current to flow. This characteristic of the varistor enables it to respond quickly and absorb a large amount of energy when a transient overvoltage occurs, effectively protecting the circuit.
The Role of the Gas Discharge Tube (GDT)
The gas discharge tube is also an important component of a surge protection device. A gas discharge tube is filled with a specific gas. When the voltage rises to its discharge voltage, the gas is ionized, forming a channel that allows current to be discharged, thus quickly discharging the current to ground. Although the response time of a gas discharge tube is slower than that of a varistor, it can handle higher currents and energy, and returns to a high-resistance state after discharge, without affecting the normal operation of the circuit.
Operating Process
Surge protectors are typically installed at the power inlet or at the front end of equipment. When a surge or transient overvoltage occurs, the surge protector activates immediately. First, the varistor responds quickly, absorbing and dispersing most of the energy, preventing damage to the circuit from a sudden voltage surge. If the voltage continues to rise, the gas discharge tube engages, further discharging excess energy to ground, thus providing dual protection.
Summary
Surge protectors, through the combined action of varistors and gas discharge tubes, effectively handle surges and transient overvoltages, protecting the safety of electrical equipment. The varistor is responsible for rapid response and absorption of initial energy, while the gas discharge tube handles higher currents and energy, thus providing reliable surge protection. When selecting a surge protector model, the appropriate surge protector needs to be determined based on the rated voltage of the equipment and the surge levels it may experience, in order to ensure the safe operation of the equipment in various power environments.
