Magnetic Actuator With Multiple Air Gaps For Faster Reaction Time

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Solution Overview

Problem

Magnetic actuators with a single air gap exhibit slow reaction times due to initial mass and large initial air gap, leading to low forces during the initial portion of travel, and attempts to improve reaction time through increased coil winding result in inefficiency and increased size.

Innovation Solution

A magnetic actuator configuration with multiple air gaps, where a first armature is accelerated to close a first air gap and then mate with a second armature to close a second air gap, enhancing reaction time without increasing coil winding turns, thus providing a more efficient solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the number of turns of trip coil winding is increased to increase force acting on magnetic actuator, then reaction time is improved, but power loss increases and overall size increases

Engineering Contradiction:
Improvereaction timeVSAvoidpower loss
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The single air gap is segmented into two separate air gaps with two distinct armatures (first and second armatures). This segmentation allows each air gap to be optimized independently, enabling faster initial response from the first armature while the second armature provides additional force amplification, thereby achieving improved reaction time without increasing coil turns or power loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first armature is positioned within the coil former and the second armature is positioned within the first armature, creating a nested configuration. This nested structure allows both armatures to be actuated by the same coil field, multiplying the effective force without requiring additional coil turns, thus improving reaction time while maintaining power efficiency.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Speed

If the number of turns of trip coil winding is increased to increase force acting on magnetic actuator, then reaction time is improved, but overall size increases

Engineering Contradiction:
Improvereaction timeVSAvoidoverall size
Core Design Contradiction:
SpeedVSVolume of stationary object

Solution Approach 1:

The nested configuration of the first armature within the coil former and the second armature within the first armature allows both magnetic components to share the same spatial envelope. This eliminates the need for additional space that would be required if separate coils were used, achieving improved reaction time without increasing overall device size.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Both armatures are actuated by a single trip coil winding, merging the actuation function into one component. This combined approach provides the force multiplication effect of multiple coils while using only one coil, thereby improving reaction time without increasing the overall size of the magnetic actuator.

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If a single air gap configuration is used, then device simplicity is maintained, but reaction time is slow due to initial mass and large initial air gap

Engineering Contradiction:
Improvereaction timeVSAvoiddevice complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The magnetic circuit is segmented into two air gaps with two armatures, allowing the first armature to close the first air gap quickly with smaller initial mass, while the second armature provides additional force. This segmentation overcomes the slowness of a single large air gap while maintaining relatively simple device architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a static single air gap configuration to a dynamic two-stage configuration where the first armature moves to close the first air gap, then the second armature moves to close the second air gap. This dynamic progression optimizes the reaction sequence, achieving faster overall response while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

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 configuration achieves faster reaction times and improved efficiency by reducing the activation current required, shortening trip time by approximately 30% without increasing the size or power loss, as demonstrated in graphical comparisons.

Implementation Method 1

a magnetic actuator having more than one air gap... a first armature is accelerated to quickly close a first air gap... The first and second armature then move toward a core to close a second air gap

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 2

The trip unit includes a magnetic actuator, which is the component that drives the tripping action... a first armature is accelerated to quickly close a first air gap

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Data Source

PatentEP2533263B1Magnetic actuator with multiple air gaps
Publication Date: 2015.08.12 ROCKWELL AUTOMATION TECH INC
  • EP2533263B1 patent drawingFigure 1
  • EP2533263B1 patent drawingFigure 2~3
  • EP2533263B1 patent drawingFigure 4~5

AI summary

Systems and methods provide a magnetic actuator having more than one air gap. After the trip unit is triggered, a first armature is accelerated to quickly close a first air gap and then mate with a second armature. The first and second armature then move toward a core to close a second air gap and reach the final combined armature position, causing a contact to open. A faster reaction time is provided, yet without increasing the number of turns of the trip coil winding, and provides a more efficient actuator.