Switching Device Quick-Release Mechanism for Arc Prevention

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Solution Overview

Problem

Existing switching devices with electromagnetic drives face challenges in quickly and permanently disconnecting current paths during short circuits or overloads due to the inertia of the drive's moving mass, leading to potentially unsafe switch-off times and risk of arc re-ignition or contact welding.

Innovation Solution

A switching device with a quick-release arrangement that includes a drive armature for moving contacts and a holding device to maintain the open position, utilizing magnetic or mechanical locking mechanisms to prevent the moving contact from falling back, ensuring permanent separation and preventing arc re-ignition or contact welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electromagnetic drive with large moving mass is used for operational switching, then the switching on process is reliable, but the switch-off time becomes too long to safely switch off a short circuit

Engineering Contradiction:
Improveswitching on reliabilityVSAvoidswitch-off speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The switching device is divided into two independent drive systems: an electromagnetic drive for normal operational switching and a separate quick-release arrangement with its own drive coil and armature for emergency short-circuit switching. This segmentation allows each drive to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The quick-release arrangement acts as an intermediary mechanism that takes precedence during short-circuit conditions. When activated, it independently overrides the operational drive to achieve rapid contact separation, ensuring safe switch-off times without affecting normal switching operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If the drive coil of the quick release is excited with short-circuit current, then very quick reaction to short circuit is achieved, but permanent opening of the contact pair is not guaranteed due to quick current decay

Engineering Contradiction:
Improvereaction speed to short circuitVSAvoidpermanent contact opening
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The holding device is pre-positioned and spring-loaded to immediately engage and secure the contacts in the open position as soon as the quick-release drive activates. This preliminary positioning ensures that even when the drive current decays, the contacts remain permanently open without risk of re-closing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The electromagnetic holding force is replaced with a mechanical holding device using springs and latches. This mechanical system maintains the contacts in the open position independently of the electromagnetic drive state, ensuring reliable permanent opening even after the drive coil current decays to zero.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for rapid and permanent disconnection of current paths during short circuits or overloads, effectively preventing arc re-ignition and contact welding, thereby ensuring safe and reliable operation.

Implementation Method 1

the drive has a bipolar electromagnetic drive unit with a movable armature and two stationary magnetic coils

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Implementation Method 2

the holding armature being held in a holding position by a magnetic force of the magnet arrangement

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3224851B1Fast triggering arrangement for cutting a current path in a switching device
Publication Date: 2019.10.23 EATON INTELLIGENT POWER LTD
  • EP3224851B1 patent drawingFigure 1~2
  • EP3224851B1 patent drawingFigure 3
  • EP3224851B1 patent drawingFigure 4

AI summary

A high-speed circuit breaking array, for breaking a current path in a switching device in the event of a short circuit or overload, has a drive for moving a drive armature from a standby position to a trigger position, wherein the movement of the drive armature is designed to act on at least one movable contact of the switching device in such a way that the current path is broken using a holding device. A switching device having a contact system has at least one fixed contact and at least one movable contact, wherein in order to make and break a current path the movable contact can be reversibly moved in relation to the fixed contact between a make position and a break position using a drive for the purpose of functional switching, and has a high-speed circuit breaking array of this type.