The VEK-12 single-spring series spring operating mechanism is an integrated product specifically designed for operating indoor high-voltage vacuum circuit breakers with a three-phase AC 50Hz, rated voltage of 12kV. It features a modular functional unit design, compact and simple structure, reliable operation, and user-friendly handling. The optimized closing functional unit design reduces the closing effort, fundamentally preventing failures such as inability to maintain closure after closing and refusal to open, while also lowering the tripping effort required for opening. The motor energy storage unit employs gear transmission, which is compact in structure and reduces mechanical failures caused by issues such as chain quality. This significantly enhances the mechanical lifespan of the circuit breaker spring mechanism (30,000 operations). Special surface treatment processes are applied to 80% of the components in the mechanism, greatly improving their corrosion resistance and ensuring consistently stable mechanical quality.