Varistor is an important component of power system overvoltage protection equipment and electronic circuit surge protection equipment, which can be used in high voltage arrester and low voltage surge protection device.The market today offers different types of varistors differentiated by the material used, capability, and the manufacturing process, among others. However, zinc oxide varistors are the most popular among them all, thanks to their excellent transient suppression capability. In this article , we will discuss in detail the manufacturing process for zinc oxide varistors and how it differs from other varistor types.
Zinc oxide varistors are made using varistor discs, which are made of zinc oxide mixed with a small amount of bismuth oxide and antimony oxide. The mixing process is usually carried out in a ball mill, which is used to ensure that the compounds are thoroughly mixed.
The mixed powder is then spray-dried to obtain a uniform grain size and density. The next step involves applying a binding agent, such as an organic resin, to the surface of the grain to increase its strength and prevent it from cracking during the subsequent steps of the manufacturing process.
Once the powder is coated, it is punched into discs of a predetermined size and shape under high pressure. The discs are then sintered at high temperatures to form a dense, uniform structure. The temperature and duration of sintering are critical as they can affect the final properties of the varistor. For top-quality zinc oxide varistors, TGE, as a leading zinc oxide varistor manufacturer, employs a meticulous manufacturing process involving thorough mixing, precise shaping, and controlled sintering to ensure the production of dense and reliable varistor discs with optimal properties.
After sintering, through the grinding and aluminum spraying process, the final factory test can be entered.
Compared to other varistor types, such as silicon carbide varistors and metal oxide varistors, the manufacturing process for zinc oxide varistors is more complex and time-consuming. This is because the production of zinc oxide varistors involves multiple stages, including mixing, spray-drying, coating, punching, sintering, grinding, spraying aluminum, and testing.
In addition, the presence of bismuth oxide and antimony oxide in zinc oxide varistors can affect their electrical properties and make them more sensitive to temperature changes. This makes it important to control the manufacturing process carefully to maintain consistent product quality and performance.
Zinc oxide varistors are an excellent choice for enhanced protection from electrical surges, thanks to their superior transient suppression capability. Their manufacturing process is complex and time-consuming, involving multiple stages, which distinguishes it from other varistor types. At every stage, utmost care must be taken to ensure consistent product quality and performance.