Metal Framework and Chassis Materials
The mobile support framework and the main body of the chassis typically utilize aluzinc-coated steel sheets. These are processed via CNC machining and finished with a powder coating; assembly involves multi-stage bending and rivet-based structural joining. This construction offers excellent mechanical strength and corrosion resistance, enabling the unit to withstand the long-term mechanical stresses associated with insertion and withdrawal operations, while serving as the load-bearing foundation for the entire structure.
Insulation Component Materials
Epoxy Resin: Formed via the APG (Automatic Pressure Gelation) process, this material is used for components such as insulating cylinders, pole assemblies, and busbar supports. It offers stable insulation performance and high mechanical strength, capable of supporting complex insulating structures, making it the mainstream choice for core insulation components in medium- and high-voltage withdrawable units.
SMC (Sheet Molding Compound): A composite of unsaturated polyester resin and glass fiber, offering a dielectric strength exceeding 20 kV. It features outstanding flame retardancy, arc resistance, and moisture resistance. It is commonly used for components like insulating partitions and shrouds, making it suitable for harsh operating environments characterized by high humidity and heavy pollution.
Flame-Retardant Modified Nylon: A thermoplastic engineering plastic used for components such as unit housings. It provides excellent insulation and wear resistance while being environmentally friendly and recyclable.
Conductive and Contact System Materials
Standard current-carrying components, such as conductive rods, utilize electrolytic copper or copper alloys to ensure low resistance and stable high-current carrying capacity.
Main contacts are made of copper-chromium (CuCr) alloy, which offers strong resistance to electrical erosion and low metal evaporation, significantly extending electrical service life. Arcing contacts-responsible for interrupting the arc-utilize silver-tungsten (AgW) or copper-tungsten (CuW) alloys, providing superior resistance to direct arc ablation.