KYN28A-12 metal clad switchgear auxiliary devices introduction
In circuit breaker trolley’s chamber, there's a pressure-releasing device at the upper part of busbar and cable chamber. while internal fault arcing happened in CB or busbar, followed by arcing appearance, the pressure increased in the cabinet and the special seal coil on door will seal the front part of the cabinet. The pressure-releasing metal plate at the top of cabinet will be opened automatically to release pressure and gas to ensure the safety of operator and cabinet.
Position interlock of secondary plug and trolley
The connection between secondary circuits of switchgear and circuit breaker’s trolley are realized by manual operating secondary plug, and the movable contactor of secondary plug is connected to CB’s trolley through a nylon corrugation extension tube. The base of secondary fixed contactor is installed on the right upper part of trolley chamber of cabinet. The secondary plug only can be connected or released when the trolley was on testing/opening position. Because of the mechanical interlock function, the secondary plug will be locked and won’t be released when the CB’s trolley is on working position. Because the closing mechanism of CB’s trolley is locked by electromagnet, the CB’s trolley only can be opened but not closed before connecting secondary plug.
The 5*50mm² earthing copper busbars have been installed independently in cable chamber, these busbars will go through neighboring cabinets and connect with cabinet’s body well. The earthing busbars are supplied for earthing elements and components. The whole body of cabinet is combined by aluminum-zinc coated steel plate and it is in good earthing condition, which ensures the safety of maintainer if touch the cabinet.