AFCI Visual Fault Indication and Memory Storage

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Solution Overview

Problem

Existing fault circuit interrupters (FCIs) lack the ability to visually indicate and store fault status, leading to confusion in identifying arc versus ground faults, and require manual intervention for reset, which can result in continued hazardous conditions if not physically present.

Innovation Solution

An arc fault detector with a non-volatile memory to store fault codes and LEDs for visual indication, allowing for the differentiation between arc and ground faults, and a push-to-test mechanism to clear stored faults, enabling reliable and robust visual feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If arc detection circuits are incorporated in circuit breakers with sophisticated arc sensors, then arc fault detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvearc fault detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The circuit breaker is designed to perform multiple functions: thermal magnetic overload detection, arc fault detection, ground fault detection, and visual fault indication. By integrating these diverse detection capabilities into a single device with a unified visual indication system, the patent reduces the need for separate specialized devices while maintaining comprehensive protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses color-coded LED indicators (green for normal, yellow for arc fault, red for ground fault) to provide intuitive visual feedback about circuit status. This transforms complex electrical fault detection into simple color-based information that is easily understood by users, reducing the perceived complexity of the system.

Inventive Principle:
Principle #32Color changes

2Device complexity

If manual reset intervention is required for fault circuit interrupters, then device complexity is reduced, but loss of time increases due to physical presence requirement

Engineering Contradiction:
Improvedevice complexityVSAvoidreset time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The circuit breaker automatically performs fault detection, fault code generation, and visual indication without requiring user intervention. The system serves itself by continuously monitoring circuit conditions and providing autonomous fault identification and status communication to users through visual indicators.

Inventive Principle:
Principle #25Self-service

3Device complexity

If fault status is not stored in memory, then device complexity is reduced, but loss of information occurs when circuit is reset

Engineering Contradiction:
Improvedevice complexityVSAvoidfault status information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The system performs preliminary action by storing fault codes in non-volatile memory immediately when a fault occurs, before the circuit is reset. This ensures that fault information is preserved and can be retrieved later through visual indication, preventing information loss that would otherwise occur upon reset.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If arc and ground faults are detected using separate circuits, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges arc fault detection circuits and ground fault detection circuits into a single integrated circuit breaker device. Both detection functions share common components including the microprocessor, memory, and visual indication system, thereby achieving precise detection of both fault types while avoiding the complexity of completely separate devices.

Inventive Principle:
Principle #5Merging (Combining)

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

Provides a reliable and robust visual indication of fault status and clearance, allowing users to identify fault causes and clear stored fault information, ensuring safer operation and reducing the risk of continued hazardous conditions.

Implementation Method 1

A non-volatile memory is provided to store the fault code.

Methodology Applied
Scientific EffectNon-volatile memory storage:

Implementation Method 2

At least one LED is provided to visually indicate the stored fault code.

Methodology Applied
Scientific EffectLight emission from LED: Light Emitting Diode

Data Source

PatentEP2345122B1Visual indication of fault status, storage and clearance in an arc fault circuit interrupter (AFCI)
Publication Date: 2015.12.02 SIEMENS INDUSTRY INC
  • EP2345122B1 patent drawingFigure 1
  • EP2345122B1 patent drawingFigure 2
  • EP2345122B1 patent drawingFigure 3

AI summary

An arc fault detector includes a means for repeatedly measuring an elapsed time. The arc fault detector also includes at least one means to perform arc detection at each repeated elapsed time. Means for initiating a tripping mechanism is activated after the elapsed time. When a fault occurs, means for generating at least one fault code is activated. The fault code is stored in at least one non-volatile memory. The fault code is selected from a group consisting of an arc fault interrupt code, a ground fault interrupt code, and a push-to-test interrupt code. The arc fault detector includes at least one means to display the fault code such as at least one LED. At least a first LED indicates an arc fault interrupt code and at least a second LED indicates a ground fault interrupt code. At least a third LED indicates a push-to-test interrupt code.