LCDI Power Cord with Conductive Shield for Leakage 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 can lead to inefficiencies and potential safety issues from leakage currents causing sparks and fires.
Innovation Solution
An alternating current (AC) power cord design featuring a conductive neutral wire shield and a conductive line wire shield, both with a conductive and non-conductive side, wrapped around insulated wires, 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.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power cords use metal sheaths made of thin copper wires for leakage detection, then leakage current detection capability is improved, but material cost increases
Solution Approach 1:
The patent replaces expensive copper wire metal sheaths with a flexible printed circuit board (FPC) that has a shorter service life but provides adequate leakage detection functionality at lower cost. The FPC is designed to be replaced periodically, accepting reduced longevity to achieve significant material cost savings while maintaining safety functionality.
Solution Approach 2:
The patent changes the material parameter from copper wire to FPC substrate material, fundamentally altering the composition and cost structure. This parameter change enables leakage detection using less expensive materials while maintaining the essential electrical detection capability through circuit design adaptations.
2Reliability
If power cords include additional conductors and metal sheaths for leakage detection, then safety against sparks and fires is improved, but device complexity increases
Solution Approach 1:
The patent combines the leakage detection function with the existing power cord structure by integrating the FPC directly into the cord assembly. The FPC serves both as the detection element and as part of the overall cord structure, eliminating the need for separate metal sheath components and reducing structural complexity.
Solution Approach 2:
The FPC performs multiple functions: it provides leakage current detection, serves as structural support, and integrates with the power cord assembly. This multi-functionality reduces the need for additional dedicated components, thereby simplifying the overall device structure while maintaining safety capabilities.
3Measurement precision
If power cords use conventional metal conductive layers for leakage detection, then detection accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical wire-based metal sheath structure with an FPC-based electrical circuit system. This substitution enables leakage detection through printed circuit traces rather than physical metal wire编织, significantly reducing manufacturing complexity and cost while maintaining detection accuracy through electronic circuit design.
Solution Approach 2:
The patent changes the detection implementation from physical metal layer construction to printed circuit board technology, altering the manufacturing parameter from metalworking to PCB fabrication processes. This parameter change enables cost-effective production while maintaining measurement precision through electronic sensing capabilities.
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 detects and interrupts leakage currents, ensuring safety by minimizing the risk of sparks and fires while reducing material costs through efficient design and functionality.
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).