Insulating Varnish for Quadrangular Wire Uniformity
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Solution Overview
Problem
Conventional insulating varnishes are poor in paintability when applied to conductors with a quadrangular cross section, leading to uneven thickness of the insulating coat, which can result in insulation breakdown and reduced performance in electric equipment.
Innovation Solution
A polyamide-imide resin varnish mixed with organosilica sol, where cyclic ketones make up 70-100 wt% of the dispersion medium, ensuring good dispersibility and uniform thickness of the insulating coat on both flat and corner regions of a conductor with a quadrangular cross section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional insulating varnish is applied to a conductor with a quadrangular cross section, then the insulating coat can be formed, but the insulating varnish drifts from corner regions toward flat regions due to surface tension, resulting in non-uniform thickness
Solution Approach 1:
The invention changes the chemical composition parameters of the insulating varnish by incorporating organosilica sol with specific cyclic ketones (70-100 wt% of dispersion medium) into the polyamide-imide resin varnish. This parameter change modifies the surface tension characteristics and flow properties of the varnish, enabling it to maintain uniform thickness during the baking process without drifting from corner to flat regions, thus resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
The invention creates a composite insulating varnish system by combining polyamide-imide resin varnish with organosilica sol containing silica particles dispersed in cyclic ketone-based dispersion medium. This composite material structure provides both the adhesion and flexibility of polyamide-imide resin and the surface tension control and uniformity of organosilica sol, enabling uniform insulating coat formation on quadrangular conductors while maintaining insulation 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 solution provides an insulated wire with improved paintability and uniform insulating coat thickness, enhancing breakdown resistance and partial discharge resistance while maintaining cost-effectiveness and simplicity in the manufacturing process.
Implementation Method 1
the organosilica sol contains dispersion medium and silica particles dispersed in the dispersion medium; cyclic ketones having boiling point in a range of 130 to 180° C. make up 70 to 100 wt % or more of the dispersion medium
Implementation Method 2
insulating varnish may be drifted from the corner regions 23 of the conductor 21 toward the flat regions 24 due to the surface tension of the insulating varnish in the process of baking
Data Source
AI summary
An insulating varnish usable for an insulating coat of an insulated wire on a conductor with a quadrangular cross section contains polyamide-imide resin varnish and organosilica sol mixed with the polyamide-imide resin varnish. The polyamide-imide resin varnish contains solvent and polyamide-imide resin. The organosilica sol contains dispersion medium and silica particles dispersed in the dispersion medium. Cyclic ketones having boiling point in a range of 130 to 180° C. make up 70 to 100 wt % or more of the dispersion medium.