Electromagnetic Trip Unit Layout for Compact Stable Protection

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Solution Overview

Problem

Existing electromagnetic trip units for electrical protection equipment are bulky and lack compactness, stability, and efficient power output, failing to meet the stringent requirements of compact integration and regulatory specifications.

Innovation Solution

A new electromagnetic trip unit design featuring a magnet attached to the armature's first end face, extending over a reduced height, creating a receiving space for the return element and hinge support, optimizing compactness without compromising stability, and using notches and yokes to integrate the magnet volume efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the magnet extends over the entire height of the armature (prior art configuration), then the magnetic circuit is complete, but the device volume and thickness increase

Engineering Contradiction:
Improveelectromagnetic trip unit volumeVSAvoidmagnetic circuit completeness
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The magnet is repositioned to extend only partially along the height of the armature (first dimension) while widening its coverage along the width (second dimension), allowing the magnetic field to effectively reach both polar faces through optimized flux paths, thereby reducing overall device thickness without compromising magnetic circuit functionality

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The magnet is strategically positioned to provide concentrated magnetic flux where most needed - adjacent to the polar faces at the air gap - rather than uniformly covering the entire armature height, optimizing magnetic effectiveness while minimizing material usage and device volume

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the spring element is positioned above the movable pallet (prior art), then the hinge can support the pallet, but the hinge becomes wide and bulky requiring a Y-shaped pallet

Engineering Contradiction:
Improvepallet stabilityVSAvoidhinge and pallet structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring element is repositioned from a vertical arrangement (above the pallet) to a horizontal arrangement (behind the pallet), allowing the hinge to be positioned at the rear of the device rather than requiring a wide front-mounted structure, thereby simplifying the overall geometry and eliminating the need for complex Y-shaped pallet designs

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of positioning the spring to push down from above (vertical force application), the spring is positioned to push horizontally from behind, inverting the direction of force application and allowing for a simpler, more compact hinge-pallet assembly

Inventive Principle:
Principle #13The other way round (Inversion)

3Volume of moving object

If the magnet and return element are positioned to optimize compactness, then device volume reduces, but contact between pallet and frame may be compromised

Engineering Contradiction:
Improveelectromagnetic trip unit volumeVSAvoidpallet contact reliability
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The magnet is positioned to concentrate magnetic flux precisely at the air gap where the pallet contacts the polar faces, ensuring strong local magnetic interaction for reliable operation, while the return spring is positioned behind the pallet to apply force without interfering with the front contact surfaces, maintaining both compactness and operational reliability

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

The design achieves improved compactness and stability, reducing the electromagnetic trip unit's thickness and volume while maintaining effective operation, aligning with regulatory and volumetric constraints.

Implementation Method 1

an electromagnetic trip unit for a protective device, preferably of the differential type, comprising at least: a coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnet surrounded by first and second magnetic legs

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP4661049A1Polarised high-sensitivity electromagnetic trip device for an electrical protection apparatus and associated electrical protection apparatus
Publication Date: 2025.12.10 HAGER ELECTRO SAS
  • EP4661049A1 patent drawingFigure 1~2
  • EP4661049A1 patent drawingFigure 3~4
  • EP4661049A1 patent drawingFigure 5~6

AI summary

The invention relates to an electromagnetic trip unit for a protective device, preferably differential, comprising: a coil (1), an armature (2) comprising a first armature piece (3) and a second armature piece (5), a magnet (10), a movable paddle (15), a return element (16), the electromagnetic trip unit is characterized in that: the magnet (10) is attached to the first end face (13) and extends from a base face (17) of the armature (2) over a first height (h1) less than a second height (h2) of the first and second armature pieces (3, 5) so as to form above a receiving space (18) located opposite the first end face (13), having a third height (h3) and configured to receive at least the return element (16), the return element (16) is arranged longitudinally in a first direction (D1) in the receiving space (18),and is coupled at one end (19) to the frame (2) and at a second end (20) to the movable pallet (15).