Current Transducer Segmented Magnetic Core Airgap Design

Solution Overview

Problem

Conventional current transducers with two airgaps and magnetic field detectors suffer from reduced accuracy due to manufacturing and positional tolerances, especially when the primary conductor is inserted or removed from the central passage.

Innovation Solution

A current transducer design featuring a two-part magnetic core with overlapping lateral branches forming two airgaps, where the magnetic field detectors are positioned in each airgap, reducing the impact of positional variations and manufacturing tolerances on measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a two-part magnetic core with two airgaps is used to improve measurement sensitivity and reduce saturation, then measurement accuracy is improved, but manufacturing precision and positional tolerance become more critical

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidairgap length consistency

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The magnetic core is divided into two separate U-shaped parts that can be assembled around the primary conductor. This segmentation allows the core to be opened for conductor insertion while maintaining two airgaps for improved measurement accuracy. Each part contains one airgap with a magnetic field detector, enabling the system to achieve high measurement precision despite the challenges of assembling two separate components.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the magnetic core is opened to allow primary conductor insertion, then ease of operation is improved, but positional tolerance and measurement accuracy deteriorate

Engineering Contradiction:

Improveconductor insertion capabilityVSAvoidairgap length consistency

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The magnetic core is divided into two separate U-shaped parts that can be assembled around the primary conductor. This segmentation allows the core to be opened for conductor insertion while maintaining two airgaps for improved measurement accuracy. Each part contains one airgap with a magnetic field detector, enabling the system to achieve high measurement precision despite the challenges of assembling two separate components.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If two airgaps with magnetic field detectors are provided in each airgap, then measurement sensitivity is improved, but device complexity increases

Engineering Contradiction:

Improvemeasurement sensitivityVSAvoidnumber of components

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic core is divided into two separate U-shaped parts that can be assembled around the primary conductor. This segmentation allows the core to be opened for conductor insertion while maintaining two airgaps for improved measurement accuracy. Each part contains one airgap with a magnetic field detector, enabling the system to achieve high measurement precision despite the challenges of assembling two separate 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 design enhances measurement accuracy and reduces inaccuracies caused by positional variations and manufacturing tolerances, while also maintaining a compact and easy-to-install transducer.

Implementation Method 1

A well-known type of current transducer comprises a magnetic core with an airgap in which a magnetic field detector, such as a Hall effect sensor is positioned to measure the magnetic field generated by the current flowing in the primary conductor.

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS12203963B2Current transducer

Publication Date: 2025.01.21 LEM INT SA

AI summary

Electric current transducer comprising a housing, a magnetic core and a magnetic field detection system, the magnetic core surrounding a primary conductor passage for receiving a primary conductor therethrough, the magnetic core comprising a first part and a second part assembled in the housing so as to form a first magnetic circuit gap and a second magnetic circuit gap, the magnetic field detection system comprising a first magnetic field detector positioned in the first magnetic circuit gap and a second magnetic field detector positioned in the second magnetic circuit gap, the first and second magnetic circuit gaps being disposed on opposing sides of magnetic core, each of the first and second parts comprising a pair of lateral branches, joined by a bridging branch.