Flexible Rogowski Coil with Articulated Jaws

Solution Overview

Problem

Existing current measurement devices using Rogowski toroids face challenges such as complex mechanical means for opening, sensitivity to external magnetic fields, rigidity, bulkiness, and manual manipulation difficulties, especially in restricted accessibility scenarios.

Innovation Solution

A flexible Rogowski torus device with a return spring for automatic closing, spacer elements with inclined ramps to facilitate cable engagement, and actuating means like control rods for remote operation, allowing for easy positioning around cables without manual handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rigid magnetic circuit with two articulated parts is used, then the cable can be engaged without interruption, but the mechanical means become complex and the assembly becomes rigid and bulky

Engineering Contradiction:

Improvecable engagementVSAvoidmechanical means

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The magnetic circuit is divided into two separate articulated jaws that can open and close independently. Each jaw is a complete magnetic circuit component that articulates about its own axis, allowing the cable to be engaged by opening one jaw while the other remains in place, simplifying the engagement process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rigid magnetic circuit is replaced with articulated jaws that can dynamically open and close. The jaws are connected through articulated mechanisms that allow controlled movement between open and closed positions, enabling easy cable engagement while maintaining magnetic circuit integrity during measurement.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If a rigid magnetic circuit with two articulated parts is used, then the cable can be engaged without interruption, but the assembly becomes rigid and bulky prohibiting accessibility

Engineering Contradiction:

Improvecable engagementVSAvoidassembly volume

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The magnetic circuit is divided into two separate articulated jaws that can open and close independently. Each jaw is a complete magnetic circuit component that articulates about its own axis, allowing the cable to be engaged by opening one jaw while the other remains in place, simplifying the engagement process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rigid magnetic circuit is replaced with articulated jaws that can dynamically open and close. The jaws are connected through articulated mechanisms that allow controlled movement between open and closed positions, enabling easy cable engagement while maintaining magnetic circuit integrity during measurement.

Inventive Principle:

Principle #15Dynamics

3Extent of automation

If manual manipulation of the torus ends is required, then the closing mechanism can be actuated, but the operation becomes delicate and tedious in restricted accessibility

Engineering Contradiction:

Improveclosing mechanism actuationVSAvoidmanual manipulation

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

A control rod is introduced as an intermediary tool to actuate the articulated jaws from a distance. The control rod transmits force through the articulated mechanism to open and close the jaws without requiring direct manual manipulation of the torus ends, making the operation feasible in restricted accessibility scenarios.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The direct manual manipulation of the torus ends is replaced with a control rod mechanism. The control rod provides mechanical advantage and allows the operator to actuate the closing mechanism from a distance, replacing the need for delicate manual handling with a more robust remote actuation system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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, automatic, and safe current measurement with reduced sensitivity to external magnetic fields, improved accessibility, and ease of assembly, while maintaining a compact design for various cable diameters.

Implementation Method 1

The voltage induced in the winding is for example proportional to the rate of change (derivative) of the current in the cable

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a return spring urging the jaws towards their close position to ensure at least partially automatic closing of the torus

Methodology Applied

Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentEP2511712B1Device for measuring electric current comprising a Rogowski coil

Publication Date: 2018.09.05 SCHNEIDER ELECTRIC IND SAS

Figure 1~2
Figure 3~4
Figure 5~7

AI summary

The device (12) has a securing unit for securing a flexible Rogowski coil (19) that occupy an open position enabling engagement around the cable and a closed position for surrounding the cable. An actuating unit moves the coil from one position to the other. The actuating unit includes two articulated jaws (21) to which the coil is secured and a separated position and a touching position is occupied by the actuating unit for placing the coil respectively in the open and closed positions. An independent claim is included for measuring assembly.