Foamed Insulated Wire Structure for Flexibility and Partial Discharge
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Solution Overview
Problem
Conventional insulated wires face challenges in achieving a balance between high partial discharge inception voltage, dielectric breakdown voltage, flexibility, and abrasion resistance, especially in high-frequency applications where dielectric loss increases, and existing materials lack low relative dielectric constants while maintaining required characteristics like heat resistance and mechanical strength.
Innovation Solution
The development of an insulated wire with a foamed insulating layer composed of thermosetting resin, featuring varying bubble densities in the thickness direction, which includes an inner and outer insulating layer of thermoplastic resin, enhancing flexibility and dielectric properties while maintaining high voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermosetting resin is used for the foamed insulating layer to improve heat resistance and mechanical strength, then partial discharge inception voltage and dielectric breakdown voltage are improved, but flexibility deteriorates making it difficult to withstand intense winding processes
Solution Approach 1:
The insulating layer is divided into multiple foamed layers with different bubble densities. The inner foamed insulating layer has a higher bubble density (5-50%) to provide flexibility for winding, while the outer foamed insulating layer has a lower bubble density (1-20%) to provide mechanical strength and high partial discharge inception voltage. This local differentiation of foam density allows each layer to optimize for its specific function.
Solution Approach 2:
The patent uses a composite structure combining multiple foamed insulating layers made of thermosetting resin with different foam densities. This composite approach allows the inner layer to provide flexibility while the outer layer provides strength and electrical performance, resolving the contradiction between flexibility and reliability.
2Strength
If the foam density of the foamed insulating layer is increased to improve mechanical strength, then abrasion resistance is improved, but flexibility deteriorates
Solution Approach 1:
Different regions of the insulating layer have different foam densities optimized for their specific requirements. The inner layer with higher foam density (5-50%) provides flexibility, while the outer layer with lower foam density (1-20%) provides abrasion resistance and mechanical strength. This local optimization resolves the contradiction between these two properties.
3Ease of operation
If conventional thermoplastic resin is used for the insulating layer to improve flexibility, then ease of winding is improved, but heat resistance and mechanical strength deteriorate
Solution Approach 1:
The patent changes the physical state of the insulating layer by creating a foamed structure from thermosetting resin. The foam structure provides flexibility similar to thermoplastic resin, while the thermosetting resin matrix maintains heat resistance and mechanical strength. This parameter change (creating foam structure) allows simultaneous achievement of flexibility and heat resistance.
Solution Approach 2:
The foamed thermosetting resin insulating layer acts as a composite material where the resin matrix provides heat resistance and strength, while the air bubbles provide flexibility and reduce dielectric constant. This composite structure resolves the contradiction between heat resistance and flexibility.
4Loss of energy
If the relative dielectric constant of the insulating material is reduced to lower dielectric loss at high frequencies, then transmission characteristics are improved, but mechanical strength and other required characteristics deteriorate
Solution Approach 1:
The patent uses foamed insulating layers with controlled bubble densities to create a porous structure. The air bubbles reduce the relative dielectric constant and dielectric loss, improving transmission characteristics at high frequencies. Meanwhile, the thermosetting resin matrix maintains mechanical strength, resolving the contradiction between dielectric performance and mechanical strength.
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 insulated wire exhibits improved partial discharge inception voltage, dielectric breakdown voltage, flexibility, and abrasion resistance, effectively addressing the limitations of conventional wires by optimizing the foamed layer structure and material selection.
Implementation Method 1
at least one foamed insulating layer composed of a thermosetting resin having bubbles
Implementation Method 2
The higher the working frequency is, the larger the dielectric loss of an insulator portion of the insulated wire becomes
Data Source
Figure 1(a)~3(b)
Figure 4~5
Figure 6
AI summary
An insulated wire, comprising at least one foamed insulating layer composed of a thermosetting resin having bubbles, directly or indirectly on the outer periphery of a conductor, wherein the foamed insulating layer has a different bubble density in the thickness direction thereof; and a rotating electrical machine.