Disconnecting Switch with Conical Sliding Surface
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Solution Overview
Problem
Conventional 3-position switches in gas-insulated switchgear have a large size due to high sliding frictional forces between moving contacts and conductors, requiring large operating devices and generating foreign objects that affect insulation, and their complex structures increase production time and cost.
Innovation Solution
A 3-position switch design with a two-hole lever and curved links connected to moving contacts, positioned on the bisector of a nearly right-angle intersection of conductors, reduces sliding friction by minimizing the angle of contact and using sliding friction reducing members on conductor surfaces, allowing linear reciprocation without complex grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the open angle between disconnecting switch-side conductor and earthing switch-side conductor is made nearly a right angle to reduce tank length, then the size of sealed tank is reduced, but the sliding frictional force between moving contacts and cylindrical sliding surfaces becomes significantly great
Solution Approach 1:
The patent replaces the cylindrical sliding surface with a conical sliding surface. The conical shape allows the moving contact to slide along an inclined surface rather than a vertical cylindrical surface, which reduces the normal force between the moving contact and the conductor wall, thereby reducing sliding frictional force while maintaining the right-angle configuration between conductors.
Solution Approach 2:
The patent changes the geometric parameter of the sliding surface from cylindrical to conical. This parameter change modifies the contact mechanics between the moving contact and the conductor, reducing the frictional force by altering the angle and distribution of contact forces during linear reciprocation.
2Device complexity
If a one-hole lever with rectilinear links is used to connect moving contacts to the operating shaft, then the structure is simple, but the frictional force requires a large drive output making the operating device large
Solution Approach 1:
By changing the sliding surface from cylindrical to conical, the patent reduces the frictional force that the operating device must overcome. This reduction in frictional resistance allows for a smaller drive output while maintaining the simplicity of the one-hole lever and rectilinear links configuration.
3Volume of moving object
If moving contacts reciprocate in cylindrical conductors with right-angle configuration, then tank size is reduced, but foreign objects affecting insulation characteristics are easily produced due to friction
Solution Approach 1:
The conical sliding surface reduces friction between the moving contact and conductor wall compared to a cylindrical surface. This reduced friction minimizes wear and prevents the generation of foreign objects that could affect insulation characteristics, while maintaining the compact right-angle configuration between conductors.
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 significantly reduces sliding friction, decreases the size of the operating device, simplifies the manufacturing process, and enhances reliability by minimizing foreign object generation and load torque, enabling a compact gas-insulated switchgear.
Implementation Method 1
an operating shaft 4 allowing the disconnecting switch-side moving contact 7a and earthing switch-side moving contact 7b to linearly reciprocate by rotating
Implementation Method 2
a two-hole lever 5 connected to the operating shaft 4 to allow an arc motion and two curved links 6a and 6b. Each one end thereof is connected to the two-hole lever 5 and the other end thereof is respectively connected to a disconnecting switch-side moving contact 7a or an earthing switch-side moving contact 7b
Implementation Method 3
reduces sliding friction by minimizing the angle of contact and using sliding friction reducing members on conductor surfaces
Data Source
AI summary
Operating shaft 4 allows disconnecting switch-side and earthing switch-side moving contacts 7a and 7b to linearly reciprocate with the rotation of operating shaft 4. Operating shaft 4 has two-hole lever 5 allow an arc motion. Each one end of two curved links 6a and 6b is connected to two-hole lever 5 and the other end of two curved links 6a and 6b is respectively connected to the disconnecting switch-side moving contact or the earthing switch-side moving contact. When the two connecting points are axisymmetric with respect to the bisector, both the disconnecting switch and the earthing switch are in an open state; when two-hole lever 5 moves at a predetermined angle to the disconnecting switch-side, the disconnecting switch is in a closed state; and when two-hole lever 5 moves at a predetermined angle to the earthing switch-side, the earthing switch is in a closed state.