Electrical Machine Assembly Using Magnetic Attraction and Non-Magnetic Separators

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Solution Overview

Problem

The assembly of electrical machines, such as permanent magnet excited generators, is complicated by high magnetic attraction forces between the rotor and stator, requiring expensive and voluminous tooling and posing health and safety risks, and existing methods to mitigate these forces are time-consuming and costly.

Innovation Solution

A method that utilizes magnetic attraction to temporarily attach winding elements to permanent magnet elements or vice versa, allowing for assembly without extra materials like screws or adhesives, and employs non-magnetic separators to protect components and facilitate correct positioning, thereby neutralizing magnetic attraction forces during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If permanent magnet modules are inserted into the rotor structure, then the rotor can be assembled, but high magnetic attraction forces cause instability and require expensive voluminous tooling

Engineering Contradiction:
Improveease of assemblyVSAvoidcomplexity of assembly tooling
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by first assembling the rotor structure without permanent magnets, then subsequently mounting the magnets onto the pre-assembled rotor. This sequence allows the rotor structure to be stabilized before magnetic elements are introduced, eliminating the need for expensive voluminous tooling during the critical assembly phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the assembly process into distinct phases: first assembling the rotor structure (yoke and spokes) without magnets, then separately mounting permanent magnet modules onto the completed rotor structure. This segmentation allows each sub-assembly to be completed independently without the complications of magnetic attraction forces during the structural assembly.

Inventive Principle:
Principle #1Segmentation

2Productivity

If multiple permanent magnet modules are mounted onto the rotor structure, then the rotor assembly is complete, but magnetic attraction forces increase making the operation time-consuming

Engineering Contradiction:
Improveassembly speedVSAvoidtime for module insertion
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent introduces non-magnetic separators as intermediary elements between the permanent magnet modules and the rotor structure. These separators reduce the magnetic attraction forces during the mounting operation, allowing modules to be installed more quickly and easily without requiring heavy guiding systems or tools, thereby reducing assembly time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs simple non-magnetic separator elements that can be easily replaced or removed after serving their purpose of reducing magnetic attraction during assembly. These inexpensive intermediary components enable faster module installation without the need for expensive reusable tooling systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If magnetic attraction forces are used to attach winding elements to permanent magnet elements, then no extra materials are required, but correct positioning and protection from magnetic forces are challenging

Engineering Contradiction:
Improvesimplicity of attachment methodVSAvoidpositioning accuracy of elements
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent uses non-magnetic separators as intermediary elements that serve dual purposes: they reduce excessive magnetic attraction forces that would cause instability, and they provide precise positioning features for the winding elements relative to the permanent magnet elements. This intermediary structure enables both simple magnetic attachment and accurate positioning without requiring additional fastening materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by incorporating non-magnetic separator elements at specific locations between the winding elements and permanent magnet elements. These localized separators provide targeted reduction of magnetic forces and precise positioning at critical interfaces, while allowing magnetic attraction to function effectively in other areas for attachment.

Inventive Principle:
Principle #3Local quality

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 method simplifies the assembly of electrical machines by leveraging magnetic forces for attachment and using non-magnetic separators to ensure correct positioning and protection, reducing the need for costly tooling and improving safety and efficiency.

Implementation Method 1

This attachment is caused by a magnetic attraction due to a magnetic field generated by the permanent magnet elements

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 2

employs non-magnetic separators to protect components and facilitate correct positioning, thereby neutralizing magnetic attraction forces during assembly

Methodology Applied
Scientific EffectMagnetic field shielding: Magnetic Field

Data Source

PatentEP3038239B1Methods of assembling an electrical machine
Publication Date: 2020.03.11 GE RENEWABLE TECH WIND BV
  • EP3038239B1 patent drawingFigure 1a~1b
  • EP3038239B1 patent drawingFigure 2a~2b
  • EP3038239B1 patent drawingFigure 3a~3b

AI summary

Method of constructing an electrical machine by assembling a first structure (a structure of a group of structures consisting of a rotor structure and a stator structure) and a second structure (the other structure of the group of structures), along with a plurality of first elements (a plurality of elements of a group of pluralities consisting of a plurality of permanent magnet elements and a plurality of winding elements) and a plurality of second elements (the other plurality of the group of pluralities). The method comprises: attaching the first elements to a rim of the first structure; attaching the second elements to the first elements, said attachment being caused by magnetic attraction; assembling the first structure with the second structure such that the second elements are positioned for their posterior attachment to a rim of the second structure; and attaching the second elements to the rim of the second structure.