Polyamide-imide Insulating Coating for Rectangular Conductors
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Solution Overview
Problem
Existing insulating coating materials for rectangular conductors often result in non-uniform thickness due to surface tension, leading to partial discharge and degradation of the insulating layer, especially under inverter surge voltage, and existing techniques struggle to maintain coating workability while achieving uniformity.
Innovation Solution
A polyamide-imide resin insulating coating material with surface-treated inorganic fine particles, specifically silica particles, is used, imparting pseudoplasticity to the coating material, which maintains low viscosity during application and increases viscosity after passing through the coating die, ensuring uniform thickness and improved coating workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the viscosity of the insulating coating material is reduced to facilitate uniform coating on circular conductors, then the coating workability is improved, but the surface tension effect is inhibited and the coating cannot maintain a uniform shape
Solution Approach 1:
The patent applies pseudoplasticity to the insulating coating material, which changes the viscosity parameter based on shear rate. At low shear rates (during coating application), the viscosity is low for good workability. At high shear rates (during shaping), the viscosity increases to maintain uniform coating shape. This parameter change resolves the contradiction between coating workability and coating uniformity.
2Manufacturing precision
If the viscosity of the insulating coating material is increased to maintain coating shape, then the coating uniformity is improved, but the coating workability deteriorates and it takes longer to form a uniform shape
Solution Approach 1:
The pseudoplastic coating material exhibits viscosity that changes with shear rate. During application (low shear), viscosity is low for ease of coating. During shaping (high shear), viscosity increases to maintain uniformity. This dynamic parameter change allows both good workability and coating uniformity without the drawbacks of consistently high viscosity.
3Volume of moving object
If multiple coating applications are used to achieve thick coating on rectangular conductors, then the coating thickness is increased, but the thickness unevenness becomes more remarkable
Solution Approach 1:
The pseudoplastic coating material maintains low viscosity during application, allowing thick coating to be applied in fewer passes. The high viscosity after application prevents sagging and maintains uniform thickness, reducing thickness unevenness compared to multiple applications of conventional materials.
4Manufacturing precision
If the application thickness per coating application is reduced to prevent unevenness due to surface tension, then the coating uniformity is improved, but the coating workability deteriorates
Solution Approach 1:
The pseudoplastic coating material allows thicker application per pass because the viscosity increases after application to prevent sagging and maintain uniformity. This eliminates the need for thin applications, improving coating workability while maintaining uniformity.
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 prevents unevenness in the insulating layer thickness, enhances coating workability, and reduces the occurrence of partial discharge, resulting in a high-quality insulating layer with improved breakdown voltage and mechanical characteristics.
Implementation Method 1
surface-treated inorganic fine particles dispersed in the polyamide-imide resin insulating coating material; wherein a viscosity measured by an E-type viscometer is 1000 to 4000 mPa·s at 30° C. and at a shear rate of 200 s−1 and 4000 to 12000 mPa·s at 30° C. and at a shear rate of 1 s−1
Data Source
AI summary
An insulating coating material includes a polyamide-imide resin insulating coating material, and surface-treated inorganic fine particles dispersed in the polyamide-imide resin insulating coating material. A viscosity measured by an E-type viscometer is 1000 to 4000 mPa·s at 30° C. and at a shear rate of 200 s−1 and 4000 to 12000 mPa·s at 30° C. and at a shear rate of 1 s−1. An insulated wire includes a rectangular conductor, and an insulating layer formed on the rectangular conductor and including the insulating coating material.