Aircraft Heated Floor Panel Ground Fault Interruption for AC Leakage
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Solution Overview
Problem
Conventional aircraft heated floor panels face electrical hazard risks due to undesirable resistance in bonding straps, leading to small AC voltages on the panel surfaces, which can cause discomfort to passengers.
Innovation Solution
A fault-protected aircraft heated floor panel with an electro-resistive heater element and a controller incorporating a ground fault interrupt circuit that detects excess current and interrupts power delivery to prevent electrical hazards, using a toroid and window comparator to monitor differential current within predefined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding straps are used to tie the floor panel to ground, then electrical safety is improved, but undesirable resistance in the bonding strap creates small AC voltage on the panel surface causing passenger discomfort
Solution Approach 1:
A ground fault interrupt circuit is introduced as an intermediary monitoring system between the power source and the heater element. This circuit continuously monitors the current flow and detects ground faults by comparing the current in the hot and neutral conductors, interrupting power delivery when a fault is detected, thereby eliminating the AC voltage on the panel surface while maintaining electrical safety
Solution Approach 2:
The ground fault interrupt circuit implements a feedback mechanism by continuously monitoring the current flow through the heater element and bonding straps. When the monitoring system detects that current is leaking to ground (indicating a ground fault), it provides feedback to interrupt the power supply, thus eliminating the harmful AC voltage on the panel surface while maintaining reliable electrical safety
2Temperature
If AC power is delivered to the heater element, then heating function is achieved, but electrical hazards are created due to potential dielectric breakdown
Solution Approach 1:
The ground fault interrupt circuit performs preliminary monitoring of the electrical system before hazards can develop. By continuously checking for ground faults and potential dielectric breakdown conditions before they result in harmful electrical shocks, the system prevents electrical hazards while maintaining the heating function
Solution Approach 2:
The system converts the potentially harmful leakage current that would indicate dielectric breakdown into a useful detection signal. The ground fault interrupt circuit uses the presence of leakage current as a diagnostic indicator to trigger power interruption, thus transforming a harmful electrical condition into a beneficial safety mechanism
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 effectively protects against electrical hazards by ensuring that excess current is detected and power is interrupted, validating bonding and grounding, and preventing reactive current from causing voltage issues on the panel surfaces.
Implementation Method 1
The resistance element within the heated floor panel typically receives AC power from an AC power source included in the aircraft. Current provided to the resistance element causes the resistance element to generate heat, thereby heating the floor panel.
Implementation Method 2
The ground fault interrupt circuit comprises a toroid through which both the power lead and the return lead pass in order to detect the differential current therebetween.
Data Source
AI summary
A fault protected aircraft heated floor panel is provided. The floor panel includes upper and lower floor panel skins and an electro-resistive heater element interposed between the upper and lower floor panel skins. The floor panel further includes a controller for controlling current delivered to the heater element, the controller including a ground fault interrupt circuit that detects excess reactive current provided to the heater element. The controller interrupts the current delivered to the heater element as a result of the ground fault interrupt circuit detecting the excess current.