Understanding the Working Principle, Mechanical Structure, and Five-Prevention Interlocking Mechanism of 35 kV Drawer-Type Vacuum Circuit Breakers

The ZN85-40.5 indoor drawer-type vacuum circuit breaker is compatible with the KYN61-40.5 indoor switch cabinet. It consists of an insulating cylinder, operating mechanism, trolley advancing mechanism, and secondary circuit. Each of the three phases (A, B, C) has one integrally cast insulating cylinder that fully encloses the arc extinguishing chamber and conductive rod. The operating mechanism is a dedicated single-stage spring-driven unit with dual energy storage modes—motorized and manual. The trolley advancing mechanism uses a screw drive with an overrunning clutch, supporting two positions: test and working. It features built-in mechanical five-prevention interlocking to prevent misoperation. The secondary control and interlocking system includes open and close coils, energy storage motor, limit switches, position auxiliary switches, and mechanical interlock plates, enabling dual electrical and mechanical locking.

Five-Prevention Interlocking Analysis: Tripping or closing operations are prohibited during trolley movement. When the circuit breaker is closed, the trolley cannot be pushed in or pulled out; operation of the switch is only allowed at the test and working positions. When the grounding switch is closed, the circuit breaker cannot be moved into the working position. When the switch is closed, the grounding switch cannot be closed.

Core Advantages of This Product: The insulating cylinder, arc extinguishing chamber, operating mechanism, and trolley base can be individually disassembled and replaced. Compatible with the full range of KYN61-compatible drawers, including isolation, PT, metering, and arrester trolleys.