Current Transducer Primary Conductor Bar Indent Design

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Solution Overview

Problem

Existing electrical current transducers are not compact, economical, robust, stable, lightweight, and easy to implement and use, particularly in current sensing applications.

Innovation Solution

A compact electrical current transducer design featuring a magnetic core with an air-gap and a magnetic field detector, where the magnetic field sensor is positioned within a reduced-width core passage section of a primary conductor bar, and an insulating housing with overmolded components for secure and cost-effective assembly, utilizing a Hall effect sensor or other magnetic field sensing technologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic core with air-gap and magnetic field detector is used for current measurement, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvecurrent measurement precisionVSAvoidtransducer structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the primary conductor bar directly into the housing structure, merging multiple components (conductor, housing, positioning features) into a unified assembly. This reduces the number of separate parts while maintaining the magnetic core with air-gap and magnetic field detector for precise current measurement.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing serves multiple functions: it provides structural support, acts as an insulator, integrates the primary conductor bar, positions the magnetic core, and houses the magnetic field detector. This multi-functionality reduces device complexity while maintaining measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Volume of moving object

If the primary conductor bar has reduced width in core passage section for indent formation, then device compactness is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvetransducer compactnessVSAvoidcore passage width tolerance

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The housing is overmolded around the core passage section of the primary conductor bar before final assembly, pre-forming the indent structure. This preliminary action accommodates dimensional variations and reduces the stringency of manufacturing precision requirements for the core passage width.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The wall thickness of the housing in the thin wall region is optimized (0.3-1.2 mm) to balance compactness with manufacturing feasibility. This parameter change allows the housing to deform slightly during assembly to accommodate the magnetic core while maintaining overall device compactness.

Inventive Principle:

Principle #35Parameter changes

3Weight of moving object

If thin wall region (0.3-1.2 mm) is used in housing for sliding through magnetic circuit gap, then device lightweighting is improved, but structural strength decreases

Engineering Contradiction:

Improvetransducer weightVSAvoidhousing structural strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The housing employs a thin wall region (0.3-1.2 mm) that acts as a flexible element, allowing the housing to deform elastically during assembly to slide through the magnetic circuit gap. This flexible design reduces weight while maintaining sufficient structural strength through controlled elasticity rather than rigid thickness.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution results in a robust, accurate, and economical current transducer that is compact and lightweight, offering improved performance and reduced manufacturing costs while maintaining precise current measurement capabilities.

Implementation Method 1

a magnetic field detector, such as a Hall effect sensor in the form of an ASIC, is positioned

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3086130B1Current transducer with integrated primary conductor bar

Publication Date: 2019.02.06 LEM INTPROP

Figure 1a~1b
Figure 2a~2d
Figure 2e~2h

AI summary

Electrical current transducer including a primary conductor bar (4) for carrying the current to be measured, a magnetic core (6) comprising a magnetic circuit gap (22), a magnetic field sensor (8) comprising a circuit board (24) and a magnetic field detector (9) positioned in the magnetic circuit gap, and an insulating housing (10) surrounding the magnetic core and magnetic field sensor, the primary conductor bar comprising connection terminal ends (12a, 12b) extending outside of the housing configured for connection to an external primary conductor. The primary conductor bar further comprises a core passage section (16) having a reduced width (W1) in comparison to the connection terminal ends (12a, 12b) extending outside of the housing thereby providing an indent (17) within which the magnetic field detector is positioned such that a central passage (18) of the magnetic core has a width (W3) less than the width (W2) of the primary conductor connection ends (12a, 12b). The insulating housing comprises a main housing portion (20) overmolded around the core passage section (16) of the primary conductor bar, the main housing portion comprising a magnetic field sensor receiving slot (44) configured to allow slidable insertion of the magnetic field sensor into the primary conductor bar indent for positioning in the magnetic circuit gap.