Polyamide-imide Insulated Wire Partial Discharge Resistance
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Solution Overview
Problem
Conventional insulated wires for electrical equipment coils, especially those used in high-voltage applications like hybrid vehicles, face challenges with insufficient partial discharge inception voltage and complex, costly fabrication processes, leading to increased risk of partial discharge and elevated production costs.
Innovation Solution
An insulated wire design featuring a dual-layer insulating coating system, where a first polyamide-imide resin coating with good adhesion and heat resistance is applied, followed by a second coating that enhances partial discharge inception voltage and flexibility, using specific chemical formulations and manufacturing processes to achieve improved performance without requiring additional extrusion steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extruded covering layer made of PPS is provided on the insulating coating to increase partial discharge inception voltage, then partial discharge resistance is improved, but fabrication process complexity and cost increase due to requiring both painting and extrusion processes
Solution Approach 1:
The patent combines the insulating coating and the protective covering layer into a single integrated insulating coating layer made of polyamide-imide resin. This eliminates the need for separate extrusion processes while maintaining both adhesion to the conductor and high partial discharge inception voltage, thus resolving the contradiction between reliability and fabrication complexity
Solution Approach 2:
The insulating coating made of polyamide-imide resin performs multiple functions simultaneously: it provides adhesion to the conductor, offers heat resistance, and achieves high partial discharge inception voltage (≥970V). This multi-functionality eliminates the need for separate extruded covering layers, reducing fabrication process complexity while maintaining reliability
2Strength
If an insulating coating is applied on the conductor to provide adhesion, then bonding between conductor and covering layer is improved, but partial discharge inception voltage remains insufficient for high-voltage applications
Solution Approach 1:
The patent uses polyamide-imide resin as a composite material that combines the adhesive properties needed for bonding with the conductor and the electrical insulation properties needed for high partial discharge inception voltage. This single composite material resolves the contradiction between adhesion strength and partial discharge resistance
3Ease of manufacture
If a single insulating coating is used to simplify fabrication, then manufacturing cost is reduced, but partial discharge inception voltage is insufficient for modern high-voltage applications
Solution Approach 1:
The patent changes the chemical composition parameters of the insulating coating by using polyamide-imide resin with specific molecular structure and properties. This material parameter change enables a single coating layer to achieve both fabrication simplicity and high partial discharge inception voltage (≥970V), resolving the contradiction between ease of manufacture and reliability
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 dual-layer coating system significantly increases partial discharge inception voltage to above 970V, while maintaining excellent adhesion and flexibility, thus reducing the risk of partial discharge and simplifying the fabrication process, thereby lowering production costs and enhancing the wire's durability.
Implementation Method 1
an insulating coating formed by applying and baking an insulating material, which is obtained by dispersing, e.g., organosilica sol in resin solution made of polyamide-imide resin
Implementation Method 2
a lifetime of the insulating coating against the partial discharge is improved (surge resistance is improved) by using an insulated wire having an insulating coating formed by applying and baking an insulating material
Data Source
AI summary
An insulated wire includes a conductor, and an insulating covering layer formed on a periphery of the conductor and including two or more insulating coatings. The insulating coatings include a polyamide-imide resin insulating material represented by chemical formula 1:where R indicates a divalent aromatic diamine including three or more aromatic rings. The insulating coatings are formed by applying and baking the polyamide-imide resin insulating material, and the polyamide-imide resin insulating material is obtained by reacting an imide group containing dicarboxylic acid with a diisocyanate, the imide group containing dicarboxylic acid being obtained by dehydration reaction of a diamine comprising a divalent aromatic diamine including three or more aromatic rings with an acid using an azeotropic solvent.