Vacuum Circuit Breaker Frame Structure for Heat and Insulation
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Solution Overview
Problem
Vacuum circuit breakers with insulating frames supporting the vacuum switch experience instability in strength, leading to degraded withstand voltage and energization performance, increased cost due to the need for multiple frames, and reduced assembly efficiency in three-phase integration structures.
Innovation Solution
A frame structure body is used as the insulating holder for the vacuum circuit breaker, featuring U-shaped frames with integrated fixation and intermediate portions, allowing for improved air convection and radiation performance without increasing the electric field, and using inexpensive materials for the fixation plate to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vacuum switch is surrounded by an insulating holder, then the insulation performance is improved, but the convection of air is suppressed and the temperature around the vacuum switch rises
Solution Approach 1:
The insulating holder is designed with a frame structure containing multiple through holes, creating a porous configuration that allows air to pass through. This enables convection cooling of the vacuum switch while the insulating material itself maintains the required insulation performance. The frame structure with openings provides both insulation and thermal management functions simultaneously.
2Strength
If the insulating holder is formed in a cylinder to surround the vacuum switch, then the structural support is improved, but the electric field outside the vacuum switch becomes high and the withstand voltage performance degrades
Solution Approach 1:
The insulating holder is segmented into a frame structure with multiple discrete support portions rather than a solid cylindrical form. This segmentation creates openings and allows the electric field to distribute more evenly, preventing field concentration that would occur with a solid surrounding structure. The frame provides structural support while maintaining electrical insulation and acceptable withstand voltage performance.
3Stability of the object's composition
If one vacuum switch is supported by two insulating frames, then the support stability is improved, but the strength as an insulating frame becomes unstable and the reliability of withstand voltage performance is lost
Solution Approach 1:
The patent merges the functions of multiple insulating frames into a single integrated insulating holder with a frame structure. This unified structure provides stable support for the vacuum switch while maintaining consistent electrical insulation properties throughout. The integrated design eliminates the reliability issues associated with multiple separate frames that may have varying strengths and insulation characteristics.
4Reliability
If one vacuum switch is supported by two insulating frames, then the support function is improved, but six insulating frames are necessary for a three-phase breaker, thereby increasing the cost
Solution Approach 1:
The insulating holder is designed as a universal multi-functional component that can support vacuum switches in three-phase breakers. The frame structure with multiple support portions allows a single insulating holder design to serve multiple phases, reducing the total number of insulating frames required from six to three or fewer, thereby reducing cost while maintaining support reliability.
5Reliability
If the fixation plate is made of a material having high energization performance such as copper or aluminum, then the energization performance is improved, but the fixation plate becomes large and expensive
Solution Approach 1:
The fixation plate is designed with local quality optimization, using metal materials with high energization performance only in the specific areas where electrical connection is required, rather than making the entire plate from expensive conductive material. This localized approach maintains energization performance at critical interfaces while reducing overall material cost and size.
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
The solution enhances the stability and reliability of the vacuum circuit breaker's withstand voltage and energization performance while reducing costs and improving assembly efficiency by using a frame structure body with U-shaped frames and inexpensive materials for the fixation plate.
Implementation Method 1
the convection of air is suppressed and the energization performance degrades
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
An object is to eliminate, through an inexpensive structure, degradation in withstand voltage performance and degradation in energization performance caused by heating in a vacuum circuit breaker. The vacuum circuit breaker includes a main circuit structure body having an insulation rod (6), a vacuum switch (8), a movable side terminal (7a), and the like and an insulating holder (1) for supporting the main circuit structure body. The insulating holder (1) is a frame structure body having opening portions (5a, 5b, 5c, 5d) in the top and bottom surfaces and both side surfaces of the section in which the vacuum switch (8) is disposed and the section in which the insulation rod (6) is disposed.