LCDI Power Cord Shielded Neutral and Line Wire Detection
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Solution Overview
Problem
Conventional power cords with leakage current detection systems are costly due to the increased cost of copper materials and require additional conductive sheaths, which complicates the detection and interruption of leakage currents, potentially leading to inefficiencies in safety and reliability.
Innovation Solution
The implementation of an AC power cord design featuring a conductive neutral wire shield and a line wire shield, both with conductive and non-conductive sides, wrapped around insulated wires, and connected in series, along with a Leakage Current Detection Interrupter (LCDI) circuit that includes a power supply and a shield integrity circuit for detecting and interrupting line voltage upon fault detection, utilizing conductive flexible media to minimize material costs and enhance detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power cords use metal sheaths made by weaving thin copper wires for leakage detection, then leakage current can be detected, but the cost of the power cord increases due to increased copper material cost
Solution Approach 1:
The patent replaces expensive copper wire metal sheaths with aluminum foil conductive layers that can be easily manufactured and applied. The aluminum foil provides sufficient conductivity for leakage detection while significantly reducing material cost compared to woven copper wire structures.
Solution Approach 2:
The patent uses composite structures combining aluminum foil with other materials to create effective conductive layers. The aluminum foil is integrated with insulating layers and other cord components to form a composite power cord structure that maintains detection capability while reducing copper content.
2Reliability
If a metal sheath surrounds two insulating layers for leakage detection, then leakage current can be detected, but the device complexity increases due to additional conductive sheaths required
Solution Approach 1:
The patent merges the shielding function and leakage detection function into a single integrated structure. The aluminum foil conductive layers serve both as electromagnetic shields and as leakage current detection elements, eliminating the need for separate metal sheaths and reducing overall structural complexity.
Solution Approach 2:
The conductive layers made from aluminum foil perform multiple functions simultaneously: they provide electromagnetic shielding, enable leakage current detection, and contribute to the overall mechanical structure of the power cord. This multi-functionality reduces the number of separate components needed.
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 design effectively detects and interrupts leakage currents, ensuring safety and reducing material costs by utilizing existing conductive components and minimizing inrush current damage, while maintaining the integrity of the power cord's shielding.
Implementation Method 1
Leakage current can be detected by detecting a voltage on the metal sheath
Data Source
AI summary
A system and method for an LCDI power cord and associated circuits is provided. The system and method include energizing shielded neutral wires and shielded line wires and monitoring the energized shields for surges, e.g., arcing, detected by a Leakage Current Detection Circuit (LCDC) and/or voltage drops, e.g., shield breaks, detected by a Shield Integrity Circuit (SIC).