Low voltage switchgear or medium voltage switchgear or high voltage switchgear
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Solution Overview
Problem
Existing methods for fixing parts to switchgear, such as using epoxy resin with brass dowels, can lead to dielectric issues and partial discharges due to mismatched threads and high electrical field densities.
Innovation Solution
Incorporating an electrically conductive plastic dowel within the insulator body, which can be moulded directly into the epoxy resin, allows for a screw or bolt to be securely attached while maintaining electrical conductivity and avoiding thread-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If self-cutting screws are directly screwed into a hole in epoxy resin, then fixation is achieved, but sharp edges at the thread create high electrical field density and potential for partial discharge
Solution Approach 1:
A brass dowel is introduced as an intermediary component between the screw and the epoxy resin. The dowel is embedded in the epoxy resin and provides a threaded interface for the screw, eliminating the need for self-cutting threads in the insulating material. This mediator prevents sharp edges and high electrical field density while maintaining secure fixation.
2Reliability
If brass dowels are molded directly in epoxy resin, then electrical conductivity is enhanced and partial discharges are prevented, but the internal thread of the brass dowel may not match the thread of the required screw
Solution Approach 1:
The brass dowel is segmented into functional zones: an upper portion with internal threading for screw engagement and a lower portion embedded in the epoxy resin. This segmentation allows the threaded portion to be precisely engineered for compatibility with standard screws while the embedded portion maintains electrical conductivity and structural integration with the insulator.
3Strength
If epoxy parts are used for fixing, then good and safe connection is achieved, but screws create sharp edges leading to high electrical field density
Solution Approach 1:
The brass dowel serves as a mediator that provides a smooth, rounded threaded interface instead of sharp self-cutting threads. The dowel's geometry distributes electrical field lines more evenly, preventing concentration at sharp edges while maintaining the strong mechanical connection between the epoxy part and the mounting hardware.
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 solution effectively mitigates partial discharges and enhances the electrical performance by using a conductive thermoplastic dowel that is cost-effective and easier to produce than traditional brass dowels.
Implementation Method 1
The electrically conductive plastic dowel is configured to connect to earth potential
Implementation Method 2
Insulating parts of a switchgear need to be fixed to other parts
Data Source
Figure 1~2
AI summary
The present invention relates to a low voltage switchgear or medium voltage switchgear or high voltage switchgear, comprising: - an insulator body (20); and - an electrically conductive plastic dowel (10); wherein the insulator body comprises the electrically conductive plastic dowel is located; wherein the electrically conductive plastic dowel is configured to connect to earth potential; and wherein the electrically conductive plastic dowel is configured to enable a screw or bolt to be screwed into the electrically conductive plastic dowel.