Refurbishing Electrical Motors Using Segmented Laminate Insulation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing methods for refurbishing electrical motors and generators are inefficient, requiring lengthy heat treatment that generates hazardous gases and risks overheating, due to the complete filling of slots which hinders uniform heat and mass exchange, leading to high energy consumption and potential damage.

Innovation Solution

A process involving heating the electrical device component to soften the laminate insulation, allowing delamination of conductors and insulation parts, followed by further heating to decompose the remaining resin and insulation, reducing the quantity of material to be removed and improving heat transfer, thus reducing energy consumption and the risk of overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If slots are completely filled with insulation material and resin, then mechanical binding and dielectric strength are improved, but heat and mass transfer during burning becomes non-uniform, leading to overheating risks and extended processing time

Engineering Contradiction:
Improvedielectric strengthVSAvoidtemperature uniformity
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The slot filling is segmented into two distinct phases: first placing the conductor and insulation material, then adding resin to fill remaining voids. This segmentation prevents complete filling with non-heat-conductive material, maintaining thermal pathways for uniform heat distribution during subsequent burning processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are placed in different locations within the slot with specific functions: insulation material provides dielectric strength where needed, while resin fills voids to reduce air pockets. This local differentiation ensures both dielectric performance and thermal conductivity are optimized in their respective zones.

Inventive Principle:
Principle #3Local quality

2Productivity

If complete burning off of organic components is performed, then conductor removal is achieved, but processing time increases to up to 8 hours and energy consumption becomes very costly

Engineering Contradiction:
Improverefurbishing speedVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The conductor is mechanically removed from the slot before the burning process. This preliminary action eliminates the need to burn off thick layers of insulation and resin that would otherwise protect the conductor, dramatically reducing the time and energy required for the subsequent burning step to remove remaining organic materials.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The process maintains continuous useful action by mechanically removing the conductor while the insulation and resin are still partially in place, then completing the removal with a shortened burning process. This continuous approach avoids the need for complete thermal decomposition from the start, reducing total processing time and energy consumption.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If complete burning off of organic components is performed, then conductor removal is achieved, but significant quantities of potentially hazardous off gases are generated

Engineering Contradiction:
Improveconductor removal efficiencyVSAvoidhazardous off gases
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The conductor is mechanically extracted before the thermal burning process. This preliminary mechanical removal reduces the volume of organic material (insulation and resin) that must be thermally decomposed, thereby proportionally reducing the generation of hazardous off-gases while still achieving complete conductor removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The conductor is extracted from the slot assembly before applying thermal energy. By taking out the conductor while the insulation structure is still intact, the subsequent burning process only needs to remove the insulation and resin materials, not the conductor insulation packages, reducing the total organic material available to generate hazardous gases.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If high temperature burning is applied to remove insulation and resin, then conductor removal is achieved, but the risk of overheating and damage to electrical device components increases

Engineering Contradiction:
Improvematerial removal efficiencyVSAvoidcomponent integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The conductor is mechanically removed before applying high-temperature burning. This preliminary action eliminates the conductor from the thermal process, preventing heat accumulation around the conductor-insulation interface that could cause overheating and damage to the electrical device components while still achieving complete conductor removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The removal process is segmented into mechanical extraction of the conductor followed by thermal removal of insulation and resin. This segmentation allows the thermal process to operate at high temperature for shorter duration on reduced material volume, improving removal efficiency while reducing cumulative heat exposure that could damage components.

Inventive Principle:
Principle #1Segmentation

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 process significantly reduces the time and energy required for refurbishment, minimizes hazardous gas production, and prevents overheating by partially opening the slots for better heat and mass transfer, resulting in a more efficient and environmentally friendly refurbishment method.

Implementation Method 1

heating the electrical device component to a temperature sufficient to soften the thermoplastic material in the nonwoven sheet and cause delamination of the film from the nonwoven sheet

Methodology Applied
Scientific EffectThermal softening: Melting

Implementation Method 2

further heating the electrical device component to thermally decompose the encapsulating resin and the remaining electrical insulation part material

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentEP2149193B1Process for refurbishing an electrical motor or generator comprising a laminate electrical insulation part and electrical motor or generator comprising said part
Publication Date: 2011.09.21 EI DU PONT DE NEMOURS & CO
  • EP2149193B1 patent drawingFigure 1
  • EP2149193B1 patent drawingFigure 2~3
  • EP2149193B1 patent drawingFigure 4

AI summary

This invention relates to an improved process for removing conductors and electrical insulation parts from electrical device components so that these devices can be refurbished with new insulation and conductors. This invention also relates to an electrical device component having an electrical winding support, a laminate electrical insulation part, an electrical conductor, and an encapsulating resin, that has a special laminate electrical insulation part that allows more efficient and environmentally friendly refurbishing.