Corona-Resistant Flat Wire Insulation

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Solution Overview

Problem

Flat enamel wires face challenges in achieving a high corona-resistant property while maintaining high adhesion and flexibility, especially when the insulation coating layer is formed by stacking layers with different viscosities and surface tensions, leading to uneven thickness and increased risk of dielectric breakdown in high-voltage environments.

Innovation Solution

A corona-resistant flat winding wire with a structured insulation coating layer comprising a surge-resistant varnish layer and an insulating varnish layer, where the surge-resistant varnish layer has a greater thickness increase rate than the insulating varnish layer, and the inorganic nanoparticle content is optimized to enhance adhesion and flexibility, with specific thickness ratios and materials used to ensure uniformity and protection against corona discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the content of inorganic insulating particles is increased to improve corona-resistant property, then the corona-resistant property increases, but the adhesion between conductor and insulation coating layer and the flexibility of insulation coating layer decrease

Engineering Contradiction:
Improvecorona-resistant propertyVSAvoidadhesion and flexibility
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by precisely controlling the content of inorganic insulating particles within a specific range (5-20 parts by weight per 100 parts by weight of polymer resin) and optimizing the thickness ratio between surge-resistant varnish layer and insulating varnish layer. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where corona resistance is sufficiently improved while adhesion and flexibility are maintained within acceptable ranges.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by creating a multi-layer insulation coating structure combining polymer resin with inorganic insulating particles (such as silica, alumina, or titanium dioxide). The composite formulation allows the organic polymer matrix to maintain adhesion and flexibility while the dispersed inorganic particles provide enhanced corona resistance, thus resolving the contradiction through synergistic material combination.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the thickness of insulation coating layer is increased to achieve desired corona-resistant property, then the corona-resistant property improves, but the adhesion and flexibility decrease

Engineering Contradiction:
Improvecorona-resistant propertyVSAvoidadhesion and flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies segmentation by dividing the insulation coating layer into two distinct functional layers: a surge-resistant varnish layer containing inorganic insulating particles for corona protection, and an insulating varnish layer for adhesion and flexibility. This layered segmentation allows each layer to be optimized independently for its specific function, resolving the contradiction between thickness-related corona resistance and operational flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by assigning different compositions and thicknesses to different regions of the insulation coating. The surge-resistant varnish layer is strategically positioned and sized (with thickness ratio controlled between 0.3-0.7) to provide localized corona protection where needed, while the insulating varnish layer maintains overall adhesion and flexibility, thus resolving the contradiction through spatial differentiation of material properties.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the insulation coating layer is formed by stacking two or more types of coating layers with different viscosities and surface tensions, then the functional properties are enhanced, but the uniformity of thickness becomes difficult to control

Engineering Contradiction:
Improvefunctional propertiesVSAvoiduniformity of thickness
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by establishing specific viscosity ranges and surface tension relationships between the surge-resistant varnish and insulating varnish layers. By controlling these physical parameters within defined boundaries, the patent ensures that the multi-layer coating process produces uniform thickness distribution, resolving the contradiction between functional versatility and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

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 effectively achieves a high corona-resistant property with improved adhesion and flexibility, reducing the risk of dielectric breakdown and partial discharge, even in high-voltage applications, by precisely controlling the thickness and composition of the insulation coating layer.

Implementation Method 1

a corona phenomenon that an electric field is concentrated may occur between or inside the insulating films, thereby causing a partial discharge to occur

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Implementation Method 2

The inorganic insulating particle improves heat conductivity, decreases thermal expansion coefficient, and increases strength, as well as giving a corona-resistant property to the enamel wire

Methodology Applied
Scientific EffectHeat conductivity: Conduction (thermal)

Implementation Method 3

an adhesion between a conductor and the insulation coating layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3217410B1Corona-resistant flat wire
Publication Date: 2020.08.12 LS CABLE & SYST LTD
  • EP3217410B1 patent drawingFigure 1~2
  • EP3217410B1 patent drawingFigure 3~4
  • EP3217410B1 patent drawing

AI summary

The present invention relates to a corona-resistant flat winding wire, and more particularly, to a corona-resistant flat winding wire with an insulation coating layer having not only high a corona-resistant property but also a high adhesive property and high flexibility.