Fault Interrupt Module with Threshold Counting for Heated Floor Panels

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Solution Overview

Problem

Conventional ground fault interrupt circuits fail to function properly on heated floor panels in aircraft due to inherent capacitance, causing false tripping when reactive current flows from heater elements to the skin, and are unable to detect dielectric breakdown effectively.

Innovation Solution

A fault interrupt module that monitors the difference in current between the input power line and neutral return line, allowing some reactive current while detecting faults, and terminates power to the load for a short time upon each fault occurrence, indefinitely if a threshold number of consecutive faults are detected, using a combination of detector circuits, timers, counters, and a solid-state relay to manage power flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power is terminated indefinitely after a fault, then safety is improved, but nuisance faults cause unnecessary permanent power loss

Engineering Contradiction:
ImprovesafetyVSAvoidoperational continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic action by providing only temporary power termination for the first few fault occurrences, then transitioning to indefinite termination only after a threshold number of consecutive faults. This periodic approach allows the system to handle nuisance faults temporarily without permanent disruption, while still ensuring safety through eventual permanent termination if faults persist

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies beforehand cushioning by allowing a certain number of fault occurrences before implementing permanent power termination. This cushioning mechanism protects against nuisance faults that may occur temporarily, while still providing ultimate safety protection if the faults represent a genuine hazard that persists over time

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a threshold-based fault counting system is implemented, then nuisance faults are handled appropriately, but the device complexity increases

Engineering Contradiction:
Improvefault handling accuracyVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or analog fault counting mechanisms with electronic digital counting circuitry. The use of electronic counters and microprocessors to track fault occurrences and implement threshold-based responses significantly reduces physical complexity while maintaining or improving the accuracy of fault handling compared to traditional mechanical approaches

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 fault interrupt module effectively prevents false power terminations and detects dielectric breakdown in heated floor panels by allowing expected reactive current loss, reducing the size and weight of the circuit and handling nuisance faults without permanent power loss, while interfacing with any load and accommodating variations in power frequency.

Implementation Method 1

The detector circuit is configured to detect faults as a difference in current between an input power line and a neutral return line

Methodology Applied
Scientific EffectElectrical current measurement: Ohm's Law

Implementation Method 2

The counter circuit configured to increment a fault count each time a fault is detected by the detector circuit

Methodology Applied
Scientific EffectEvent counting:

Implementation Method 3

The switch circuit configured to terminate power to a load upon the fault count reaching a threshold count within a threshold time period

Methodology Applied
Scientific EffectElectrical switching: Relay

Data Source

PatentEP3525307B1Fault interrupt module
Publication Date: 2022.11.16 GOODRICH CORP
  • EP3525307B1 patent drawingFigure 1
  • EP3525307B1 patent drawingFigure 2A
  • EP3525307B1 patent drawingFigure 2B

AI summary

A fault interrupt module includes a detector circuit (14), a counter circuit (26), and a switch circuit (34). The detector circuit is configured to detect faults as a difference in current between an input power line and a neutral line. The counter circuit configured to increment a fault count each time a fault is detected by the detector circuit, and the switch circuit is configured to terminate power to a load upon the fault count reaching a threshold count within a threshold time period.