Arc Runner Assembly for DC Circuit Interruption

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Solution Overview

Problem

Existing arc extinction systems in circuit interrupters are primarily designed for AC applications and struggle to effectively extinguish DC arcs, which can persist longer and occur at varying polarities, posing challenges in protecting DC circuits, especially in applications requiring higher current interruption capabilities.

Innovation Solution

An improved arc runner assembly with a pair of arc runners situated on opposite sides of a stationary contact, utilizing rare earth permanent magnets to direct positive and negative DC arcs away from the contact, facilitating their extinction by communicating them towards arc plates for interruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single arc runner is used adjacent to a stationary contact, then the arc can be directed in one direction towards the arc chute, but the circuit interrupter cannot effectively handle both positive and negative DC arcs with varying polarities

Engineering Contradiction:

Improvecapability to interrupt both positive and negative DC arcsVSAvoidnumber of arc runners

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The arc runner is divided into two separate arc runners positioned on opposite sides of the stationary contact. Each arc runner is responsible for directing arcs of a specific polarity, enabling the circuit interrupter to handle both positive and negative DC arcs effectively without requiring a single complex adjustable mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The two arc runners are positioned asymmetrically on opposite sides of the stationary contact, with each arc runner configured to direct arcs in opposite directions. This asymmetric arrangement allows the system to adapt to varying arc polarities by providing dedicated pathways for each polarity type.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If arc extinction systems are designed for AC applications with arcs lasting only one-half cycle, then the design can be simplified, but the system becomes ineffective for DC applications where arcs can exist for longer periods

Engineering Contradiction:

Improveeffectiveness in extinguishing DC arcsVSAvoiddesign complexity for DC arc extinction

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The arc runner assembly is designed to serve multiple functions: it can effectively extinguish both AC arcs and DC arcs of varying polarities. The dual arc runner configuration provides universal applicability across different arc types and durations, making the circuit interrupter suitable for both AC and DC applications without requiring separate specialized systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If the arc runner is positioned to direct arcs away from the stationary contact in one direction, then positive DC arcs can be extinguished effectively, but negative DC arcs with opposite polarity cannot be directed properly

Engineering Contradiction:

Improvearc direction control for both polaritiesVSAvoidconfiguration of arc runners

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Instead of using a single arc runner that would need to adjust its position or orientation to handle both polarities, the invention uses two arc runners positioned in opposite directions. Each arc runner is fixed in its orientation and directs arcs away from the stationary contact in its respective direction, effectively handling opposite polarities through inverted positioning rather than adjustable mechanisms.

Inventive Principle:

Principle #13The other way round (Inversion)

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 arc runner assembly effectively extinguishes both positive and negative DC arcs, enhancing the capability of circuit interrupters to manage DC circuits by rapidly directing arcs towards arc plates for interruption, regardless of polarity, and can be used in both DC and AC applications.

Implementation Method 1

utilizing rare earth permanent magnets to direct positive and negative DC arcs away from the contact

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS8947181B2Arc runner assembly and circuit interrupter

Publication Date: 2015.02.03 EATON INTELLIGENT POWER LTD

AI summary

An arc runner assembly for use in a circuit interrupter provides a pair of arc runners that are situated at opposite sides of a stationary contact of the circuit interrupter. If used in a DC application, the arc runner assembly is configured to communicate a positive DC arc along one of the arc runners in a first direction away from the stationary contact and is further configured to communicate a negative DC arc along the other arc runner in another direction away from the stationary contact. The arc runner assembly additionally includes a support that is electrically engaged with a conductor of the circuit interrupter on a surface opposite that on which the stationary contact is disposed. The improved arc runner assembly advantageously facilitates extinction of electrical arc and extinguishes both positive and negative DC arcs in a DC application.