Circuit breaker spring mechanism ZN13

The circuit breaker spring mechanism ZN13 is a core power component designed specifically for the ZN13 series medium voltage vacuum circuit breakers. It uses spring energy storage as the driving source and is widely used in 10kV-40.5kV medium voltage distribution systems, industrial substations, and urban distribution networks due to its "precise action, high reliability, and strong adaptability". It provides stable power for circuit breaker opening and closing operations and ensures the safe operation of the medium voltage power grid. ​
1、 Core working principle: Efficient logic driven by spring energy storage
1. Energy storage system design
In response to the operational power requirements of the ZN13 series circuit breaker (closing operation power ≥ 120J), the mechanism adopts a single set of main spring energy storage structure, and the core parameters and operating logic are as follows:
Spring selection: The main spring is made of 60Si2MnA alloy spring steel with a diameter of 18mm. After quenching at 950 ℃ and tempering at 420 ℃, the tensile strength reaches 1800MPa. When the maximum deformation is 28mm, it can store 150J of energy and meet the power requirements for circuit breaker closing; ​
Energy storage method: Supports "electric+manual" dual-mode. The electric energy storage is equipped with a 0.75kW single-phase motor (AC220V/380V optional), which drives the energy storage shaft to rotate through a two-stage gear reduction (reduction ratio 1:80). The cam compresses the spring, and the energy storage is locked by the pawl after completion, taking ≤ 12 seconds. The manual energy storage can be completed by shaking the handle (speed 25r/min) for ≤ 35 turns, suitable for emergency scenarios. ​
2. Collaborative opening and closing actions
The transmission connection between the mechanism and the ZN13 circuit breaker has been precisely calibrated to ensure synchronization and accuracy of the action
Closing process: After receiving the closing signal, the DC220V closing electromagnet (suction force ≥ 60N) pushes the release component, releases the pawl, and releases the main spring energy. The main shaft of the circuit breaker is driven to rotate through the steel transmission link (φ 12mm), and the moving contact is closed. The closing time is ≤ 70ms, ensuring fast power supply to the circuit; Simultaneously, the opening spring synchronously stretches and stores energy to prepare for opening; ​
Opening process: When a short circuit (short circuit current ≤ 31.5kA) or overload is detected, the opening electromagnet (or manual handle) will operate, the opening lock will release, the opening spring will release energy, and the moving contact will be driven to open. The opening time is ≤ 25ms, and the vacuum arc extinguishing chamber will be used to quickly cut off the arc. The opening rebound amount is ≤ 2mm, which meets the GB/T 1984 standard.