Electromagnetic Relay Lorentz Force Contact Stability

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Solution Overview

Problem

Conventional electromagnetic relays face challenges in preventing separation between movable and fixed contacts due to increasing electromagnetic repulsive forces as current increases, leading to larger contact pressure springs and relay sizes.

Innovation Solution

The design incorporates a coil, a movable member, fixed contact retainers, a plate-like movable element with movable contacts, and strategically placed magnets to generate Lorentz forces that counteract electromagnetic repulsive forces, maintaining contact without increasing the necessary elastic force of the contact pressure spring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elastic force of the contact pressure spring is increased to prevent separation between movable contacts and fixed contacts due to electromagnetic repulsive force, then contact reliability is improved, but the body size of the contact pressure spring and the electromagnetic relay enlarges

Engineering Contradiction:

Improvecontact reliabilityVSAvoidrelay size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent converts the harmful electromagnetic repulsive force that causes contact separation into a beneficial Lorentz force that pushes the movable element toward the fixed contacts. By strategically positioning magnets near specific movable contacts, the current flowing through the contacts interacts with the magnetic field to generate a force that counteracts the repulsive force, thereby improving contact reliability without requiring a larger contact pressure spring

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the physical parameters of the system by introducing magnetic fields and utilizing Lorentz forces. By adjusting the position and strength of magnets, and by optimizing the current path through the movable contacts, the system achieves a new force balance where electromagnetic Lorentz forces supplement the mechanical spring force, allowing for a reduction in spring size while maintaining contact reliability

Inventive Principle:

Principle #35Parameter changes

2Power

If the electromagnetic repulsive force increases with higher current values, then power transmission capability is improved, but the separation between movable contacts and fixed contacts increases

Engineering Contradiction:

Improvepower transmission capabilityVSAvoidcontact stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The patent transforms the harmful effect of increased electromagnetic repulsive force (which occurs with higher current) into a beneficial effect. The same high current that generates stronger repulsive force also generates stronger Lorentz forces when interacting with the magnetic field, and these Lorentz forces are directed to push the movable contacts against the fixed contacts, thereby maintaining contact stability even at high power transmission levels

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent creates a composite force system combining mechanical spring force and electromagnetic Lorentz force. The contact pressure spring provides baseline contact force, while the electromagnetic Lorentz force generated by the interaction between current and magnetic field provides additional stabilizing force that increases with current, creating a synergistic effect that maintains contact stability across a wide range of power transmission levels

Inventive Principle:

Principle #40Composite materials

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 effectively inhibits separation between movable and fixed contacts by optimizing Lorentz forces to oppose electromagnetic repulsive forces, allowing for compact relay designs without compromising contact integrity.

Implementation Method 1

a coil for generating an electromagnetic force when energized, a movable member capable of being attracted by the electromagnetic force of the coil

Methodology Applied

Scientific EffectElectromagnetic force: Electromagnetic Induction

Implementation Method 2

strategically placed magnets to generate Lorentz forces that counteract electromagnetic repulsive forces, maintaining contact without increasing the necessary elastic force of the contact pressure spring

Methodology Applied

Scientific EffectLorentz force: Lorentz Force

Data Source

PatentUS8519811B2Electromagnetic relay

Publication Date: 2013.08.27 ANDEN CORP

AI summary

In an electromagnetic relay, length from a movable contact to an end portion of a movable element on a first end side is set greater than length from the movable contact to another end portion of the movable element on a second end side opposite to the first end side. A direction of a Lorentz force acting on a portion of the movable element from the movable contact to the end portion of the movable element on the first end side is conformed to a direction for bringing fixed contacts and movable contacts into contact with each other. Thus, separation between the movable contacts and the fixed contacts due to an electromagnetic repulsive force can be inhibited.