Switch Contact Segmentation for Arc Duration Control

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Solution Overview

Problem

Switches face challenges in reducing the size and cost of operating devices due to the need for high-speed operation of movable contacts to minimize arc duration between contacts, leading to increased complexity and expense.

Innovation Solution

A switch design featuring a movable contact and an intermediate contact that reciprocate along an operating shaft, with an arc generator and insulating guide, allowing for reduced operating speed without prolonging arc duration through coordinated movement and energization, utilizing a conductor for contacts and an insulator for the partition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the movable contact is operated at high speed to reduce arc duration, then the arc duration between the movable contact and the fixed contact is reduced, but the size and cost of the operating device increase

Engineering Contradiction:
Improvearc durationVSAvoidsize and cost of operating device
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the contact system into three separate contacts (first movable contact, intermediate contact, and fixed contact) instead of using a single movable contact. This segmentation allows the arc generation and contact closure to occur in distinct stages, enabling the movable contact to move at lower speeds while still achieving rapid arc extinction through the coordinated action of multiple contacts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate contact serves as a mediator between the movable contact and the fixed contact. It first establishes contact with the movable contact to generate and extinguish the arc, then subsequently contacts the fixed contact to complete the grounding function. This intermediary mechanism allows the main movable contact to operate at reduced speeds without compromising safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the movable contact is operated at high speed to reduce arc duration, then the safety of turn-on is improved, but the manufacturing cost increases

Engineering Contradiction:
Improvesafe turn-on capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the contact system into multiple contacts with distinct functions, the patent achieves reliable safe turn-on capability through the coordinated action of these contacts. The intermediate contact specifically handles the arc generation and extinction, while the movable and fixed contacts handle the grounding function, distributing the reliability requirements across multiple components rather than demanding high-speed operation from a single contact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate contact performs preliminary action by first contacting the movable contact to generate and extinguish the arc before the movable contact reaches the fixed contact. This preliminary arc extinction action ensures safety is established in advance, allowing the main grounding contact to close at a slower, more controlled speed.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the movable contact is operated at high speed to reduce arc duration, then the operational safety is improved, but the operating device size increases

Engineering Contradiction:
Improveoperational safetyVSAvoidoperating device size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent segments the contact system into multiple contacts arranged in a compact configuration along the operating shaft. This segmentation allows each contact to have a smaller, more focused function, enabling the overall device to achieve high operational safety through coordinated action rather than requiring a single large, high-speed operating mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multiple contacts are arranged in a nested or compact sequence along the operating shaft, with the intermediate contact positioned between the movable and fixed contacts. This nested arrangement allows the device to maintain a compact size while incorporating the functional complexity of multiple contacts, avoiding the need for a larger operating device that would be required for high-speed single-contact operation.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 reduces the size and cost of the operating device by decreasing the speed of the movable contact while maintaining arc duration, enhancing design flexibility and operational efficiency.

Implementation Method 1

an energizing portion that energizes the second contact in the first direction

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

an arc generator that is placed on the side of the first direction with respect to the first abutting portion and generates an arc between the second contact and the arc generator

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Data Source

PatentEP3451475B1switch
Publication Date: 2020.04.15 MITSUBISHI ELECTRIC CORP
  • EP3451475B1 patent drawingFigure 1
  • EP3451475B1 patent drawingFigure 2
  • EP3451475B1 patent drawingFigure 3

AI summary

A switch (1) includes a first contact (2) and a second contact (3) that are placed along an operating shaft (50) and can reciprocate with respect to each other. An end of the second contact (3) opposite to an end thereof on the side of the first contact (2) is housed in a housing space (44) of a housing box (42). The pressure in the housing space (44) is increased due to an arc generated when the first contact (2) approaches the second contact (3). The increased in the pressure causes the second contact (3) to move toward the first contact (2).