Vacuum Switch Coil Springs for Electric Field Distribution
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Solution Overview
Problem
Vacuum switches with solid isolation resin covering the circumference of the switch chamber face dielectric breakdown due to electric field concentration at the angular parts of the insulating cylinder, which existing solutions fail to adequately address.
Innovation Solution
The implementation of first and second coil springs, disposed around the outer circumference of the insulating cylinder and end plates, respectively, to cover the angular parts and distribute the electric field, ensuring the coil springs are electrically connected and molded with solid isolation resin to prevent field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circumference of the switch chamber is covered with solid isolation resin, then isolation performance is improved, but electric field concentration occurs at the ends of the insulating cylinder causing dielectric breakdown
Solution Approach 1:
A conductive coating layer is applied to the outer surface of the insulating cylinder to serve as an intermediary between the solid isolation resin and the insulating cylinder. This coating layer relieves electric field concentration at the ends of the insulating cylinder, preventing dielectric breakdown while maintaining the isolation performance provided by the solid isolation resin.
2Object-affected harmful factors
If a doughnut-shaped electric field relieving shield is disposed at the ends of the insulating cylinder, then electric field concentration is relieved, but the angular part at the end cannot be covered leading to dielectric breakdown
Solution Approach 1:
Instead of using a uniform doughnut-shaped shield, a conductive coating layer is applied locally to the outer surface of the insulating cylinder, specifically covering the angular parts at the ends where electric field concentration occurs. This localized approach ensures complete coverage of critical areas while preventing dielectric breakdown.
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 configuration effectively suppresses dielectric breakdown by covering the angular parts of the insulating cylinder, enhancing isolation reliability and preventing electric field concentration, thus improving the overall insulation performance.
Implementation Method 1
a first coil springs, each of which is disposed around the outer circumference of one end plate while touching the end plate and an end face of the insulating cylinder, and a second coil springs, each of which is united to one of the first springs and disposed around the outer circumference of the insulating cylinder so as to cover the angular part of the end face of the insulating cylinder
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A vacuum switch having a fixed electrode, a movable electrode facing the fixed electrode, an insulating cylinder (2A,2B), end plates (3A,3B) covering both axial ends of the insulating cylinder, a vacuum chamber internally accommodating the fixed electrode and the movable electrode, and a solid isolation (21) resin molded on the outside of the vacuum chamber, whereby, a first coil springs (30), each of which is disposed around the outer circumference of one end plate while touching the end plate and an end face of the insulating cylinder, and a second coil springs (31), each of which is united to one of the first springs and disposed around the outer circumference of the insulating cylinder so as to cover the angular part of the end face of the insulating cylinder, and the end plates, the end faces of the insulating cylinder, and the first and second coil springs are electrically connected.