Aircraft Heated Floor Panel Ground Fault Interrupt Control
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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 surface, which can cause discomfort to passengers despite existing safety measures.
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, using a toroid and window comparator to ensure safe current delivery, and includes a temperature control mechanism with a solid-state relay to manage heating.
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 surface resulting in electrical hazard discomfort
Solution Approach 1:
A ground fault interrupt circuit is introduced as an intermediary device between the power source and the heater element. This circuit includes a toroid that detects differential current and a window comparator that compares the detected current against reference levels, thereby mediating the electrical connection to eliminate harmful AC voltage while maintaining safety
Solution Approach 2:
The ground fault interrupt circuit implements feedback by continuously monitoring the differential current through the toroid and comparing it against reference levels using the window comparator. When the detected current exceeds safe thresholds, the circuit provides feedback to interrupt power delivery, thereby eliminating the harmful AC voltage on the surface while maintaining electrical safety
2Temperature
If AC power is delivered to the heater element, then heating function is improved, but electrical hazards are created due to potential dielectric breakdown
Solution Approach 1:
The ground fault interrupt circuit performs preliminary detection of differential current before harmful electrical hazards can develop. The toroid continuously monitors current flow and the window comparator prepares to interrupt power delivery if unsafe conditions are detected, thereby preventing dielectric breakdown and electrical hazards while maintaining heating capability
Solution Approach 2:
The ground fault interrupt circuit acts as an intermediary between the AC power source and the heater element. It mediates the power delivery by detecting differential current through the toroid and controlling power flow based on window comparator output, thereby enabling safe heating operation while preventing electrical hazards
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 interrupting current when excess reactive or real current is detected, validating bonding and grounding, and ensuring safe operation by removing power in case of faults, thus enhancing passenger safety.
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
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AI summary
A fault protected aircraft heated floor panel (10) is provided. The floor panel (10) includes upper and lower floor panel skins (16,20) and an eiectro-resistive heater element (24) interposed between the upper and lower floor panel skins (16,20). The floor panel (10) further includes a controller (30) for controlling current delivered to the heater element (24), the controller (30) including a ground fault interrupt circuit that detects excess reactive current provided to the heater element (24). The controller (30) interrupts the current delivered to the heater element (24) as a result of the ground fault interrupt circuit detecting the excess current.