Leakage Detection Circuit with Twin Induction Coils and Self-Check
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Solution Overview
Problem
Existing leakage detection protection circuits are complex in structure, difficult to assemble, and lack reliable protection against reversed wire connections and temperature-related component damage, with precision requirements that are hard to meet in processing and assembly.
Innovation Solution
A quick-action leakage detection protection circuit with a regular self-checking function, featuring twin induction coils, a control chip, a trip coil with an iron core, a reset button, and a self-checking silicon controlled rectifier, along with a simplified main circuit switch and current limiting diode, which reduces assembly complexity and prevents component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional normally-open switches are added to implement reversed wire connection protection, then protection function is improved, but device complexity increases and assembly difficulty increases
Solution Approach 1:
The patent combines the reversed wire connection protection function with the existing main circuit switch by integrating a normally-closed switch into the same switch assembly. This merging approach allows the protection function to be added without increasing the number of separate components, thereby improving reliability while minimizing the increase in device complexity and assembly difficulty.
2Ease of operation
If seesaw structure and flexible lead are used in main circuit switch, then switching function is achieved, but processing precision requirements increase and assembly difficulty increases
Solution Approach 1:
The patent replaces the complex seesaw mechanical structure with a simpler direct-actuation mechanism where the dynamic contact lever is directly connected to the trip coil actuator. This substitution eliminates the need for precise mechanical balancing and flexible lead connections, significantly reducing processing precision requirements while maintaining the switching function.
3Device complexity
If current limiting circuit is not provided in reversed wire connection path, then circuit structure is simplified, but components may be damaged due to temperature rise
Solution Approach 1:
The patent introduces a current limiting resistor as an intermediary component in the reversed wire connection path. This resistor limits the current flow during reversed connection conditions, preventing excessive temperature rise and component damage. The current limiting resistor is integrated into the existing circuit path without requiring separate protection circuits, thus providing component protection while minimizing the increase in circuit complexity.
4Ease of operation
If dynamic contact lever is disconnected under pressure and closed after release, then reset function is achieved, but action precision requirements increase and assembly difficulty increases
Solution Approach 1:
The patent inverts the traditional reset mechanism by making the dynamic contact lever normally-closed and having it open upon actuation rather than closing upon release. The reset button directly actuates the trip coil to open the contacts, and the contacts remain open until a separate reset operation closes them. This inversion simplifies the mechanical action requirements and reduces assembly precision needs while maintaining the reset function.
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 provides reliable earth leakage protection, reversed wire connection protection, and timed self-checking functions while simplifying the circuit structure and reducing assembly precision requirements, ensuring stable and reliable operation and preventing component damage from temperature rise.
Implementation Method 1
twin induction coils for detecting leakage current and low resistance failure
Implementation Method 2
a trip coil allowing the reset button to drive the main circuit switch to be closed or open/disconnected by driving a built-in iron core under the action of a magnetic field
Data Source
AI summary
A quick-action leakage detection protection circuit with a regular self-checking function is provided. The quick-action leakage detection protection circuit may include a power input end, a power load end, a power user end, twin induction coils for detecting leakage current and low resistance failure, a control chip, a trip coil in which an iron core is disposed, a reset button, a self-checking chip, and a self-checking silicon controlled rectifier. The reset button may be linked with a main circuit switch, an analog path switch, and a normally-open self-checking path switch. The main circuit switch may include a pair of dynamic contact levers extended from the power load end, a first pair of static contact ends extended from the power input end passing through the twin induction coils, and a second pair of static contact ends extended from the power user end. In some embodiments, a first end of the trip coil may be connected to a live line end of the power input end and to the live line of the power load end via the first normally-closed switch. And, a second end of the trip coil may be connected to a neutral line end of the power load end via a second normally-closed switch.