PCB Coil Arc Fault Detection in Compact Circuit Interrupters

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Solution Overview

Problem

Circuit interrupters such as GFCIs and AFCIs face space constraints when integrated into electrical receptacles, requiring innovative designs to efficiently accommodate their components while maintaining functionality.

Innovation Solution

The use of printed circuit board coils and a microcontroller-based control system with integrated ground fault and arc fault detection units, which include coils configured to sense current and analyze signals for fault conditions, allowing for compact integration within the receptacle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If traditional wire-wound coils are used in circuit interrupters, then the coils can effectively sense current and detect faults, but the device occupies excessive space within the electrical receptacle

Engineering Contradiction:
Improvedevice footprintVSAvoidfault detection capability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent replaces traditional wire-wound coils with printed circuit board (PCB) coils, substituting a mechanical wire-winding process with a printed circuit fabrication process. This substitution dramatically reduces the space required for the sensing coils while maintaining their electrical functionality for current sensing and fault detection

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

Solution Approach 2:

The patent changes the physical form and geometric parameters of the coils from three-dimensional wire-wound structures to planar PCB traces. This parameter change allows the coils to be integrated directly into the circuit board layout, minimizing the overall device footprint while preserving the magnetic field sensing capability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple fault detection functions (GFCI and AFCI) are integrated into a single receptacle, then user safety is enhanced, but the device complexity increases

Engineering Contradiction:
Improvesafety protectionVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines ground fault detection (GFCI) and arc fault detection (AFCI) functions into a single integrated control system. The microcontroller unit consolidates multiple detection algorithms and control logic into one processor, enabling dual functionality without proportionally increasing overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a universal control system that performs multiple safety functions. The same microcontroller and sensor infrastructure are used for both ground fault detection and arc fault detection, allowing the device to provide comprehensive safety protection while avoiding the need for separate dedicated hardware for each function

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

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

This solution enables effective detection and interruption of faults while minimizing the device's footprint, enhancing safety and usability within the limited space of electrical receptacles.

Implementation Method 1

coils configured to sense current and analyze signals for fault conditions

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP3827450B1Circuit interrupting device having printed circuit board coils
Publication Date: 2024.02.28 HUBBELL INC
  • EP3827450B1 patent drawingFigure 1
  • EP3827450B1 patent drawingFigure 2A
  • EP3827450B1 patent drawingFigure 2B

AI summary

A circuit interrupter including a line conductor, a neutral conductor, a printed-circuit board coil, and a test circuit. The printed-circuit board coil has an aperture configured to receive the line conductor. The test circuit is electrically connected to the printed-circuit board coil. The test circuit is configured to determine an arc fault condition based on a signal of the printed-circuit board coil.