Insulated Wire With Varying Permittivity For Corona Discharge Suppression
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Solution Overview
Problem
Conventional insulated wires used in rotating electrical machines face challenges in durability due to insufficient insulation performance at high voltages, particularly with corona discharge issues at curved coil end portions, and require complex and costly production processes.
Innovation Solution
The use of an insulated wire with a coating layer where the relative permittivity differs in the length or circumferential direction, achieved by foaming the insulating material, which reduces the relative permittivity and enhances durability without a complex production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulated wires are used with uniform insulation thickness, then production process is simple, but insulation performance is insufficient at high voltage and corona discharge occurs
Solution Approach 1:
The patent applies local quality by varying the insulation thickness according to the specific functional requirements of different wire sections. The slot housing portion uses thicker insulation (first thickness) for enhanced voltage withstand capability, while the coil end portion uses thinner insulation (second thickness) to reduce corona discharge. This localized differentiation of insulation quality resolves the contradiction between improved insulation performance and production simplicity.
2Reliability
If insulation thickness is increased to suppress corona discharge, then durability improves, but production cost and process complexity increase
Solution Approach 1:
The patent implements local quality by applying different insulation thicknesses to different sections of the wire. The slot housing portion receives thicker insulation for durability, while the coil end portion receives thinner insulation sufficient for its needs. This localized approach improves durability where required without unnecessarily increasing production cost across the entire wire.
Solution Approach 2:
The patent applies partial action by providing enhanced insulation (excessive action) only in the slot housing portion where high voltage stress occurs, rather than uniformly across the entire wire. The coil end portion receives just sufficient insulation thickness, avoiding excessive material usage and production cost while maintaining adequate durability.
3Reliability
If different insulating materials are used for slot housing portion and coil end portion, then insulation performance is optimized, but production process becomes complicated
Solution Approach 1:
The patent applies local quality by differentiating insulation thickness rather than material composition. The slot housing portion uses the first insulating material with greater thickness, while the coil end portion uses the same material with lesser thickness. This approach achieves optimized insulation performance for each section while maintaining production simplicity by using a single material type throughout.
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
This approach significantly improves the durability of insulated wires by suppressing corona discharge and partial discharge deterioration, allowing for a simpler and more cost-effective production method while maintaining high performance in rotating electrical machines.
Implementation Method 1
achieved by foaming the insulating material, which reduces the relative permittivity
Data Source
AI summary
An insulated wire in which at least one layer of an insulating material is coated around a conductor, wherein the insulated wire has a part in which relative permittivity is different in a length direction or a circumferential direction in an identical coating layer and a method of producing the same, and a rotating electrical machine and a method of producing the same.