Medium-voltage surge arrester 3EJ series

class Ifor electrical installationsfor electrical networks

Siemens Energy 3EJ silicone rubber surge arresters with Cage Design™ Siemens Energy 3EJ silicone surge arresters with cage design are ideally suited for reliable protection against overvoltages in medium-voltage distribution networks. Siemens Energy 3EJ cage design surge arresters are ideally suited to provide reliable protection for: • Generators • Motors • Arc furnaces • Dry-type transformers • Airfield lighting systems • Cable sheathing • Capacitors and capacitor banks • Converters for drives The cage, made of fiberglass-reinforced plastic (FRP) rods, provides a rigid, reinforced structure ensuring high mechanical strength. The silicone rubber housing is directly molded onto the metal oxide (MO) blocks and the surrounding cage made of FRP rods. This creates a reliable seal that prevents moisture ingress and partial discharges. The MO resistors are not surrounded by a rigid mechanical coating, which is why no critical increases in pressure can occur in the surge arrester in the extremely rare event of an overload. The arc can escape directly through the soft silicone housing without damaging the mechanical structure. No internal parts are ejected in the process. The innovative Siemens cage design is very secure. The silicone rubber is highly hydrophobic. This keeps any conductive moisture from forming on the surface, and dirt deposits are rendered harmless as a result of the hydrophobic transfer. Silicone is highly fire-retardant and self-extinguishing in the event of fire. These properties ensure the reliable, maintenance-free operation of 3EJ surge arresters.