Insulated Wire Adhesion Layer for Partial Discharge Resistance

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Solution Overview

Problem

Enameled wires used in electrical equipment face challenges with partial discharge resistance, particularly after being formed into coils, due to stress and bending, leading to cracks and film separation, which reduces their resistance to surge voltage.

Innovation Solution

An insulated wire design featuring a partial-discharge-resistant layer with inorganic fine particles dispersed in a base resin coating material, an adhesion layer with an adhesion improver, and additional layers for toughness and lubrication, ensuring the adhesion strength remains high even after 20% elongation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an enameled wire is used under poor conditions (bent or twisted) during coil formation, then the wire can be formed into a coil, but the insulating film develops cracks or film separation, reducing partial discharge resistance

Engineering Contradiction:

Improvecoil formation capabilityVSAvoidpartial discharge resistance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The insulating coating is divided into multiple functional layers: a base resin layer providing flexibility and crack resistance, and an inorganic fine particle layer providing partial discharge resistance. This segmentation allows each layer to specialize in one function, resolving the contradiction between flexibility during coil formation and resistance to partial discharge.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses a composite insulating coating combining organic base resin materials with inorganic fine particles (silica, alumina, titania, or zirconia). This composite structure provides both the flexibility needed for coil formation and the partial discharge resistance required for reliable operation, directly resolving the technical contradiction.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the insulating film is made thicker to improve partial discharge resistance, then partial discharge resistance improves, but the wire becomes less flexible and more prone to cracking during coil formation

Engineering Contradiction:

Improvepartial discharge resistanceVSAvoidflexibility and crack resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Different regions of the insulating coating have different properties: the base resin layer provides flexibility and crack resistance, while the inorganic fine particle layer provides partial discharge resistance. This local differentiation of material properties allows the coating to simultaneously achieve both flexibility and partial discharge resistance without requiring increased overall thickness.

Inventive Principle:

Principle #3Local quality

3Reliability

If conventional inverter-surge-resistant enameled wire is used, then partial discharge resistance is improved, but adhesion strength decreases significantly after elongation during coil formation

Engineering Contradiction:

Improvepartial discharge resistanceVSAvoidadhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

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 design enhances adhesion strength and maintains excellent partial discharge resistance after coil formation, preventing film separation and improving flexibility and durability.

Implementation Method 1

an insulating coating material including a base resin coating material and an inorganic fine particle dispersed in the base resin coating material

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

a decrease rate in adhesion strength of the adhesion layer to the conductor after 20% elongation relative to that before the elongation is less than 25%

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8927865B2Insulated wire

Publication Date: 2015.01.06 PROTERIAL LTD

AI summary

An insulated wire includes a conductor, a partial-discharge-resistant layer formed on the conductor and including an insulating coating material including a base resin coating material and an inorganic fine particle dispersed in the base resin coating material, and an adhesion layer formed between the conductor and the partial-discharge-resistant layer and including an insulating coating material including the base resin coating material and an adhesion improver. A decrease rate in adhesion strength of the adhesion layer to the conductor after 20% elongation relative to that before the elongation is less than 25%.