Electromagnetic Actuator Ribs Reduce Air Gap and Power

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Solution Overview

Problem

Existing electromagnetic actuators for electrical contactors require high power due to large air gaps between the pallet and spreader plate, leading to increased mass and spring stiffness, which either increases power requirements or compromises shock resistance performance.

Innovation Solution

The introduction of ribs reduces the average air gap distance between the spreader plate and movable vane, enhancing magnetic field control and force generation at constant power, while minimizing the moving mass and necessary magnetic intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the active take-off area of the spreader plate and vane is increased to reduce electromagnetic power, then the mobile mass increases, but this leads to increased electromagnetic power requirements and oversized return springs

Engineering Contradiction:
Improveelectromagnetic powerVSAvoidmobile mass
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The spreader plate is segmented by adding ribs that divide the air gap into multiple smaller regions. This segmentation increases the effective interaction area between the magnetic field and the vane without increasing the overall mobile mass, as the ribs are integrated into the existing spreader plate structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a new dimensional feature (ribs extending from the spreader plate) to increase the effective take-off area. By adding this vertical dimension element, the magnetic interaction area is expanded without increasing the horizontal footprint or overall mass of the movable components.

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

2Power

If the stiffness constant of the return spring is reduced to decrease electromagnetic power, then the shock resistance performance deteriorates

Engineering Contradiction:
Improveelectromagnetic powerVSAvoidshock resistance performance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The air gap is segmented by ribs into multiple smaller regions, which increases the magnetic field intensity and effectiveness. This allows the use of a less powerful electromagnetic actuator while maintaining the same operational performance, thereby reducing the required electromagnetic power without compromising shock resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the geometric parameters of the air gap by introducing ribs at specific positions and heights. This modifies the magnetic circuit parameters to increase flux density and magnetic force generation efficiency, allowing reduced electromagnetic power consumption while maintaining actuator performance and shock resistance.

Inventive Principle:
Principle #35Parameter changes

3Power

If ribs are added to reduce the air gap and increase magnetic field intensity, then the moving mass increases, but the invention aims to minimize this increase

Engineering Contradiction:
Improvemagnetic field intensityVSAvoidmoving mass
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The ribs are merged with the spreader plate as a single integrated component rather than separate additions. This combining approach minimizes the total mass increase, as the ribs utilize the existing material and structural framework of the spreader plate, adding only the necessary minimal material to create the air gap segmentation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ribs are strategically positioned and dimensioned to provide local magnetic field enhancement only where needed for optimal magnetic coupling. This localized approach ensures that the mass increase is minimized while achieving the desired increase in magnetic field intensity at the critical interaction zones between the spreader plate and vane.

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

This solution allows for effective control of the pallet's position with reduced power consumption and increased electromagnetic force, maintaining shock resistance performance without substantial actuator size modifications.

Implementation Method 1

use coils to generate a magnetic field in order to control a movable pallet

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The electromagnetic power required to maneuver the pallet is high due to the large air gap

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 3

the ribs reduce the average air gap distance between the spreader plate and the movable vane, which allows effective control of the position of the vane, with an increase in the magnetic field generated by the coil

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 4

an oversizing of the return spring to meet the required shock resistance performance

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3198624B1Electromagnetic actuator and electrical contactor comprising such an actuator
Publication Date: 2019.10.30 SCHNEIDER ELECTRIC IND SAS
  • EP3198624B1 patent drawingFigure 1
  • EP3198624B1 patent drawingFigure 2
  • EP3198624B1 patent drawingFigure 3~4

AI summary

This electromagnetic actuator (2) for manoeuvring an electrical contactor comprises a fixed part (4) including at least one coil (44A, 44B) for generating a magnetic field centred on a longitudinal axis (X2), at least one core (46A, 46B) for concentrating the magnetic flux, this core being installed within the coil and provided with a fan-out plate (464) for the magnetic flux which defines an active surface (S464) perpendicular to the longitudinal axis as well as at least one magnetic flux return element (42). This actuator also comprises a reed (6) movable in translation along the longitudinal axis (X2) and with respect to the fixed part (4), between a first position remote from the active surface (S464) and a second position close to this surface, under the effect of a loading induced by the magnetic field, as well as at least one member (8A, 8B) for elastic return of the reed (6) to a predetermined position from among the first position and the second position. The fan-out plate (464) is provided with at least one rib (468) for closing the magnetic field lines between this fan-out plate and the reed (6), this rib protruding with respect to the active surface (S464) on the side of the reed and made at the level of an edge (466) of the fan-out plate.