Outdoor electrical equipment is exposed to the natural environment for a long time and faces many challenges such as wind, sun, rain and dust. Electrical devices in humid environments are also threatened by moisture at all times. For two-phase capacitors, the intrusion of moisture and dust may have serious consequences. Once moisture enters the interior of the capacitor, it will react chemically with the electrode, causing electrode corrosion. The electrode is the core component of the capacitor to store and release electrical energy. After the electrode is corroded, its performance will gradually decline, which will affect the charging and discharging efficiency of the capacitor. More seriously, moisture may cause short circuit failures, making the capacitor unable to work properly, and even causing safety accidents such as electrical fires. The accumulation of dust should not be underestimated. It will adhere to the heat dissipation surface of the capacitor and hinder the dissipation of heat. The capacitor will generate a certain amount of heat during operation. If the heat cannot be dissipated in time, it will cause the internal temperature to rise, affecting the service life and performance stability of the capacitor. ​
The reason why the rubber seal of the Two-Phase Capacitors Screw Cover can effectively prevent the entry of moisture and dust is closely related to its unique material properties and structural design. Common rubber materials used for screw cover sealing, such as EPDM and silicone rubber, have excellent physical and chemical properties. EPDM has good weather resistance and can maintain its physical and chemical properties under long-term sunlight, wind and rain erosion, and is not easy to age or crack. It is also very resistant to chemical corrosion and can resist the erosion of a variety of chemicals. Even in an environment with slightly corrosive gases or liquids, it can play a good sealing role. Silicone rubber has excellent high temperature resistance. Under high temperature conditions, it will not soften and lose elasticity like ordinary rubber, and can still maintain a good sealing effect. At the same time, silicone rubber is also very flexible and can buffer external mechanical stress to a certain extent and protect the structural integrity of the capacitor. ​
From the perspective of structural design, the rubber sealing part is cleverly arranged in a key position in the screw cover. When the screw cover is tightened with the capacitor housing, the rubber seal will fit tightly with the contact surface to form an effective barrier. This tight fit is achieved through precise size design and reasonable installation process. The contact surface between the screw cover and the capacitor housing has been finely processed, with high surface flatness, which can fully contact with the rubber seal to reduce the gap. The rubber seal itself also has a certain elasticity. When squeezed, it can better fill the gap and further improve the sealing effect. In some occasions where the sealing requirements are extremely high, a multi-layer sealing structure is also used, that is, on the basis of the rubber seal, a layer of auxiliary sealing materials such as waterproof tape is added. The multi-layer sealing structure is like multiple lines of defense, layer by layer of protection, which greatly enhances the sealing performance and ensures that moisture and dust cannot enter the capacitor. ​
Take the street lighting system as an example. The capacitor in the street lamp is usually installed inside the lamp pole. Although the lamp pole can provide certain protection, on rainy days, rainwater may still enter through the gaps or other weak parts of the lamp pole, and dust will also flow into the lamp pole with the air. If there is no good sealing measure, the capacitor will be damaged by moisture and dust. The rubber sealing part of the screw cover, like a loyal guard, firmly guards the capacitor. It effectively prevents the entry of rainwater and dust, creating a relatively closed and clean internal environment for the capacitor. In such an environment, the capacitor can operate stably, provide continuous and stable electricity for the street lamps, and ensure the normal lighting of the street lamps. Whether it is a stormy night or a dusty weather, as long as the rubber sealing part of the screw cover maintains good performance, the street lamp can light up as usual and illuminate the way forward for pedestrians. ​
In other outdoor electrical equipment, such as wind turbines and solar power generation devices, two-phase capacitors are also facing the test of harsh environments. Wind turbines are at high altitudes for a long time, and they not only have to withstand strong winds, but also may encounter extreme weather such as heavy rain and hail. Solar power generation devices have to withstand long-term exposure to sunlight and wind and rain. Under these complex environmental conditions, the rubber sealing part of the screw cover always plays an important role. It isolates the outside world from moisture and dust, allowing the capacitor to work in a stable environment, ensuring the normal operation of wind turbines and solar power generation devices, and providing people with clean and reliable electricity. ​
In electrical devices in humid environments, such as electrical equipment in basements and electrical control systems in sewage treatment plants, moisture is the main threat to capacitors. The air humidity in the basement is high, which is prone to condensation; there is a large amount of water vapor and corrosive gases in the sewage treatment plant. In these environments, the moisture resistance and corrosion resistance of the rubber sealing part of the screw cover are particularly important. It can effectively prevent humid air and water vapor from entering the capacitor and prevent the electrode from being corroded by moisture. At the same time, the rubber sealing part can also play a good barrier role for possible corrosive gases, protecting the capacitor from chemical corrosion, thereby ensuring the normal operation of the electrical device and maintaining the stability of the entire system.