Magnet Evaluating Device Eddy Current Loss

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Solution Overview

Problem

Conventional magnet evaluating devices require a large, costly setup with a well-insulated sample chamber and a strong magnetic field to measure eddy current loss, leading to increased size and expense.

Innovation Solution

A magnet evaluating device with an evaluation magnet and a master magnet, both formed by connecting magnetic sections with insulating material, an excitation coil generating an alternating magnetic field, and a detection coil to measure eddy currents, allowing for direct evaluation without the need for a large sample chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a well-insulated sample chamber is used to capture eddy current loss as heat, then measurement accuracy is improved, but device size and complexity increase

Engineering Contradiction:
Improveeddy current loss measurement accuracyVSAvoidsample chamber insulation structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the thermal measurement system (thermocouple in insulated chamber) with an electromagnetic detection system. The detection coil directly measures eddy current-induced magnetic fields, eliminating the need for thermal insulation structures while achieving accurate eddy current loss evaluation through electromagnetic induction principles

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

Solution Approach 2:

The patent introduces a detection coil as an intermediary element that indirectly measures eddy current loss by detecting the magnetic field generated by eddy currents. This intermediary approach allows non-contact measurement without requiring direct thermal coupling or insulated chambers

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a large magnetic field generation device is used to reach the magnet through the sample chamber, then magnetic field strength is improved, but device size increases

Engineering Contradiction:
Improvemagnetic field strengthVSAvoiddevice volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent extracts the magnetic field generation function from a separate large device and integrates it directly into the evaluation apparatus. The excitation coil is positioned to generate magnetic fields directly at the magnet location without needing to penetrate through insulated chamber walls, reducing overall device volume while maintaining field strength

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the excitation coil and detection coil into a compact integrated structure that surrounds or positions near the magnet. This combined configuration allows both magnetic field generation and eddy current detection to occur in close proximity, eliminating the need for separate large-scale magnetic field generation equipment

Inventive Principle:
Principle #5Merging (Combining)

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

Enables precise and cost-effective measurement of eddy current loss by comparing voltage or current generated in the detection coil during the passage of the evaluation and master magnets, reducing device size and cost while maintaining accuracy.

Implementation Method 1

an excitation coil that generates an alternating magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a detection coil for detecting an eddy current occurring in the magnet

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

detecting an eddy current occurring in the magnet

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2960669B1Magnet evaluating device and method
Publication Date: 2022.04.06 NISSAN MOTOR CO LTD
  • EP2960669B1 patent drawingFigure 1(a)~1(c)
  • EP2960669B1 patent drawingFigure 2(a)~2(c)
  • EP2960669B1 patent drawingFigure 3~4

AI summary

[Problem] To provide a magnet evaluating device with a simpler configuration that is capable of evaluating eddy current loss occurring in a magnet. [Solution] A magnet evaluating device 1 evaluates an evaluation magnet 51 by passing the evaluation magnet 51, which is formed by connecting a plurality of magnetic sections 101 with insulating material 103 in between, and a master magnet 55 of the same form through an alternating magnetic field generated by an excitation coil 12, measuring the eddy current occurring in the magnetic section 101 as voltage or current occurring in a detection coil 13 and comparing the measured value for the evaluation magnet 51 and the measured value for the master magnet 55.