Slot Motor Arc Extinction via Segmented Plates

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Solution Overview

Problem

Existing electrical switching apparatus, such as circuit breakers, face challenges in extinguishing arcs during current interruption due to insufficient current-induced magnetic force and gas dynamics, leading to undesirable electrical current flow and contact material vaporization, and prior solutions involving large permanent magnets are costly and increase size.

Innovation Solution

Incorporating a plurality of high-energy permanent magnets on a support element within the slot motor, which generates a strong magnetic field to attract and drive arcs into an arc chute, combined with outgassing to facilitate arc extinction, allowing for effective interruption of both low and high current levels without increasing the size of the arc chute.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large permanent magnets are placed in the arc chute to drive the arc into the arc chute, then the arc interruption capability is improved, but the cost increases and the size of the arc chute increases

Engineering Contradiction:
Improvearc interruption capabilityVSAvoidsize of arc chute
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention divides the arc chute into multiple sections with multiple sets of arc plates, each set having different orientations. This segmentation allows the arc to be broken into multiple segments and redirected through different paths, improving arc interruption capability without requiring a single large permanent magnet or increasing the overall arc chute volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the arc chute have arc plates with different orientations and configurations tailored to local requirements. The first set of arc plates has a first orientation while the second set has a second orientation different from the first, creating localized magnetic field interactions that effectively drive and extinguish arcs in different regions without uniformly increasing the entire arc chute size.

Inventive Principle:
Principle #3Local quality

2Reliability

If large permanent magnets are placed in the arc chute to drive the arc into the arc chute, then the arc interruption capability is improved, but the cost increases

Engineering Contradiction:
Improvearc interruption capabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The arc chute is divided into multiple sections with multiple sets of arc plates, each set having different orientations. This segmentation allows the arc to be broken into multiple segments and redirected through different paths, improving arc interruption capability without requiring a single large permanent magnet or increasing the overall arc chute volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the arc chute have arc plates with different orientations and configurations tailored to local requirements. The first set of arc plates has a first orientation while the second set has a second orientation different from the first, creating localized magnetic field interactions that effectively drive and extinguish arcs in different regions without uniformly increasing the entire arc chute size.

Inventive Principle:
Principle #3Local quality

3Reliability

If current-induced magnetic force is increased to force the arc into the arc chute, then the arc extinction is improved, but the device complexity increases

Engineering Contradiction:
Improvearc extinctionVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The arc chute structure itself generates the necessary magnetic field interactions through its configuration of arc plates with different orientations. The system uses the arc's own current and the geometric arrangement of conductive arc plates to create the magnetic forces needed for arc extinction, eliminating the need for external permanent magnets or complex control systems.

Inventive Principle:
Principle #25Self-service

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 enables efficient arc extinction across a range of current levels, reducing costs and size, while maintaining effective arc interruption capabilities, by leveraging the magnetic force and outgassing mechanism to drive arcs into the arc chute, improving upon prior art slot motors.

Implementation Method 1

a plurality of permanent magnets including a first permanent magnet and a second permanent magnet, the first permanent magnet being located on the first leg, the second permanent magnet being located on the second leg

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

generates a strong magnetic field to attract and drive arcs into an arc chute

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 3

The arc plates are electrically insulated from one another such that the arc is broken-up and extinguished by the arc plates

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3384512B1Electrical switching apparatus and slot motor therefor
Publication Date: 2020.01.01 EATON INTELLIGENT POWER LTD
  • EP3384512B1 patent drawingFigure 1
  • EP3384512B1 patent drawingFigure 2
  • EP3384512B1 patent drawingFigure 3~4

AI summary

A slot motor (100,200,300) is for an electrical switching apparatus (2). The slot motor includes a support apparatus including a support element (102) having a first leg (104,204) and a second leg (106,206) located opposite the first leg, the first leg having a first inner surface (110), the second leg having a second inner surface (112) facing the first inner surface; a plurality of permanent magnets (180,182,280,282,284,286,380,382) including a first permanent magnet (180,280,380) and a second permanent magnet (182,282,382), the first permanent magnet being located on the first leg, the second permanent magnet being located on the second leg; and a number of U-shaped plates (130,140) coupled to the support element. The first inner surface and the second inner surface are located between the first permanent magnet and the second permanent magnet.