Glass-Ceramic Insulation for Electric Machine Conductor Bars

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Solution Overview

Problem

Current insulation materials for electric machine conductor bars, primarily mica, have low thermal conductivity and a thermal expansion coefficient mismatch with copper, limiting heat transfer and increasing the risk of mechanical failure.

Innovation Solution

A polycrystalline glass-ceramic material is developed by heat-treating silicate glass flakes, offering higher thermal conductivity and a thermal expansion coefficient closer to copper, replacing traditional mica insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mica insulation material is used, then electrical insulation is provided, but thermal conductivity is low limiting heat transfer

Engineering Contradiction:
Improveelectrical insulationVSAvoidthermal conductivity
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies composite materials by combining glass-ceramic particles with a binding agent to create an insulation material that integrates the electrical insulation properties of glass-ceramic with improved thermal conductivity, replacing traditional mica while maintaining electrical performance and enhancing heat transfer capabilities

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by modifying the thermal conductivity parameter of the insulation material through the use of glass-ceramic particles, which have inherently higher thermal conductivity than mica, thereby improving heat transfer while maintaining electrical insulation properties

Inventive Principle:
Principle #35Parameter changes

2Reliability

If mica insulation material is used, then insulation is provided, but coefficient of thermal expansion mismatch with copper increases mechanical stress

Engineering Contradiction:
ImproveinsulationVSAvoidmechanical stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies parameter changes by selecting glass-ceramic particles with a coefficient of thermal expansion matched to copper, thereby reducing thermal expansion mismatch and the associated mechanical stress during thermal cycling, while maintaining insulation performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by tailoring the thermal expansion properties of the insulation material specifically at the interface with copper conductors, using glass-ceramic particles whose thermal expansion characteristics are selected to match copper, thereby locally reducing stress at the critical interface

Inventive Principle:
Principle #3Local quality

3Reliability

If traditional mica insulation is used, then electrical insulation is achieved, but heat transfer efficiency is limited

Engineering Contradiction:
Improveelectrical insulationVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies composite materials by creating a composite insulation material consisting of glass-ceramic particles dispersed in a binding agent, where the glass-ceramic phase provides both electrical insulation and enhanced thermal conductivity, thereby improving heat transfer efficiency while maintaining electrical insulation

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies mechanics substitution by replacing the natural layered structure of mica with a particulate glass-ceramic composite, which provides more efficient thermal conduction pathways through the insulation layer, thereby substituting the limited thermal transfer mechanism of mica with a more efficient heat transfer mechanism

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 glass-ceramic insulation material enhances heat transfer and reduces mechanical stress and failure risk, providing improved thermal management and reliability for electric machine conductor bars.

Implementation Method 1

heat treating a silicate glass to obtain a glass-ceramic material

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

heat treating a silicate glass to obtain a glass-ceramic material

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP3119727B1An insulation material and a method to produce
Publication Date: 2021.01.20 GENERAL ELECTRIC TECH GMBH
  • EP3119727B1 patent drawingFigure 1
  • EP3119727B1 patent drawingFigure 2~3

AI summary

The present disclosure relates to an insulation material for a conductor bar of an electric machine. An object of the invention is to provide for an alternative insulation material in the field of electric machines. The object is solved by an insulation material for a conductor bar for an electric machine comprising glass-ceramic flakes made from a heat treated silica glass precursor in the shape of flakes. Further disclosed are a corresponding method and the use of glass-ceramic flakes as an insulation material for a conductor bar of an electric machine