Circuit Breaker Tripping Linkage for Interphase Insulation
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Solution Overview
Problem
Existing molded case circuit breakers experience breakdowns between circuit breaker poles due to direct contact of the linkage rod's rotating shaft, which is made of metal and conducts high current, leading to insulation issues.
Innovation Solution
The circuit breaker design incorporates insulated transmission rods and bimetallic strips that connect the armature to the linkage rod, increasing insulation gaps and creepage distances, and includes a tripping system with a bimetal adjusting structure to enhance insulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the linkage rod's rotating shaft is made of metal to ensure mechanical strength and rotational function, then the mechanical reliability is improved, but the insulation performance deteriorates due to high current conduction causing breakdown between circuit breaker poles
Solution Approach 1:
The patent introduces an insulated transmission rod as an intermediary component between the armature and the linkage rod. This insulated transmission rod transfers the tripping force while preventing direct electrical contact between the high-current armature and the metal linkage rod, thus resolving the contradiction between mechanical reliability and insulation performance
Solution Approach 2:
The patent segments the force transmission path into multiple components: the armature, the insulated transmission rod, and the linkage rod. This segmentation allows each component to perform its specific function while maintaining proper insulation boundaries, preventing current leakage between poles
2Device complexity
If the armature directly contacts the linkage rod to simplify the structure, then the device complexity is reduced, but the insulation performance deteriorates due to direct current conduction paths
Solution Approach 1:
The insulated transmission rod serves as a necessary intermediary that maintains insulation while transmitting mechanical force. Although it adds a component, it prevents the more complex problem of insulation breakdown and subsequent failures, achieving better overall system reliability
Solution Approach 2:
The patent employs composite material principles by combining insulating materials with mechanical transmission components. The insulated transmission rod integrates both insulation properties and mechanical strength, allowing the system to achieve both electrical isolation and reliable force transmission
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively prevents interphase breakdowns between circuit breaker poles by enhancing insulation and creepage distances, thereby improving the overall insulativity and safety of the circuit breaker.
Implementation Method 1
after a short-circuit current flows through a conductive plate and the armature is enabled to rotate and contact a magnetic yoke
Implementation Method 2
each group of tripping mechanism further comprises a bimetallic strip and a bimetal transmission rod
Data Source
AI summary
A circuit breaker that includes circuit breaker poles, an operating mechanism and a tripping system. Each circuit breaker pole includes a pole housing and a contact system that includes a moving contact mechanism and a static contact. The operating mechanism drives the moving contact mechanisms. The tripping system includes groups of tripping mechanisms and an adjusting mechanism. Each group of tripping mechanisms includes a conductive plate, a magnetic yoke and an armature. The conductive plate passes through the magnetic yoke. Each circuit breaker pole has a group of tripping mechanisms. Each contact system is electrically connected to a corresponding conductive plate. Each adjusting mechanism includes a linkage rod. Each group of the tripping mechanisms includes an insulated transmission rod having one end inserted into the pole housing and connected to the armature, and another end that protrudes out of the pole housing and trips the operating mechanism.