Air Circuit Breaker Safety Shutter for Fast Terminal Insulation

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Solution Overview

Problem

Conventional insulating shutters for extendable air circuit breakers are cumbersome to assemble and disassemble, and they do not respond quickly when the circuit breaker retracts or extends, leading to potential arc faults due to inrush currents.

Innovation Solution

A safety shutter system comprising a base unit coupled to a cradle, a shutter unit spaced apart from the base unit, and a cam unit that exposes or accommodates terminals to ensure quick insulation activation or deactivation as the circuit breaker moves in or out of the cradle, using sliding plates and rails with inclined surfaces to guide the shutter unit's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional insulating shutter with a separate actuating lever is used, then the shutter can be manually operated to convert between insulated and non-insulated modes, but the operation is cumbersome and insulation cannot be performed quickly

Engineering Contradiction:
Improveease of shutter operationVSAvoidtime for insulation activation
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The insulating shutter is designed to automatically open or close based on the retraction or extension of the circuit breaker, eliminating the need for a separate actuating lever. The shutter responds to the circuit breaker's movement itself, achieving self-service operation that is both simple and rapid.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The shutter is pre-positioned and automatically activates insulation before the circuit breaker fully extends from the cradle, preventing arc faults by establishing insulation in advance during the withdrawal process.

Inventive Principle:
Principle #10Preliminary action

2Extent of automation

If an insulating shutter with one portion coupled to the circuit breaker and the opposite portion coupled to the cradle is used, then the shutter automatically opens or closes when the circuit breaker retracts or extends, but assembly and disassembly are cumbersome

Engineering Contradiction:
Improveautomatic shutter operationVSAvoidease of assembly and disassembly
Core Design Contradiction:
Extent of automationVSEase of manufacture

Solution Approach 1:

The insulating shutter is divided into a first shutter portion coupled to the circuit breaker and a second shutter portion coupled to the cradle, with a gap between them. This segmentation allows the shutter to be easily assembled and disassembled while maintaining automatic operation during circuit breaker retraction and extension.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shutter system utilizes the spatial dimension created by the gap between the first and second shutter portions, allowing automatic operation through relative movement while simplifying assembly and disassembly operations.

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

3Reliability

If the conventional insulating shutter is used, then it provides insulation between terminals and circuit breaker, but the shutter does not respond quickly when the circuit breaker retracts or extends into or from the cradle

Engineering Contradiction:
Improveinsulation effectivenessVSAvoidresponse speed of shutter
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The insulating shutter is designed to dynamically respond to the circuit breaker's movement. The shutter automatically opens or closes in real-time based on whether the circuit breaker is retracting into or extending from the cradle, ensuring rapid response and maintained insulation effectiveness.

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

The safety shutter quickly activates or deactivates insulation, preventing arc accidents and facilitating easy maintenance by ensuring rapid electrical connection or disconnection of terminals during the circuit breaker's movement, thus enhancing operational safety and maintenance convenience.

Implementation Method 1

a cam unit extending from the base unit in a protruding manner, wherein the cam unit passes through the shutter unit

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3913756B1Safety shutter of withdrawable air circuit breaker
Publication Date: 2024.11.13 LS ELECTRIC CO LTD
  • EP3913756B1 patent drawingFigure 1
  • EP3913756B1 patent drawingFigure 2
  • EP3913756B1 patent drawingFigure 3

AI summary

A safety shutter of the present disclosure comprises: a base unit; a shutter unit; and a cam unit. The base unit is coupled to a cradle of an air circuit breaker, and a terminal connected to a main circuit passes through the base unit. The shutter unit is coupled to the base unit so as to be spaced apart at a predetermined interval, and accommodates the terminal in the space between the shutter unit and the base unit. The cam unit extends from the base unit and penetrates the shutter unit. The shutter unit deactivates insulation by exposing the terminal in the direction of the air circuit breaker when the air circuit breaker is inserted in the direction of the base unit.