Ground Fault Circuit Interrupter with Reverse Wiring Protection
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Solution Overview
Problem
Existing ground fault circuit interrupters (GFCIs) lack effective reverse wiring protection and an end-of-life indicator, leading to potential safety hazards and mechanical resistance issues in releasing the latch mechanism.
Innovation Solution
A GFCI design incorporating a low friction pivotal latch mechanism, reverse wiring protection using a second solenoid coil, and an end-of-life indicator circuit that illuminates an LED when the device is nearing the end of its life, ensuring safe operation and easy reset without high mechanical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical actuator is used in traditional GFCI, then the device structure is simple, but reverse wiring protection is not provided and performance is limited
Solution Approach 1:
The solenoid coil serves multiple functions: it acts as both the ground fault detection actuator and the reverse wiring protection mechanism. When properly wired, the solenoid remains energized to hold the latch engaged; when reversed or disconnected, it de-energizes to prevent operation, providing dual protection functionality through a single component.
Solution Approach 2:
The control circuit acts as an intermediary between the electrical inputs and the mechanical latch system. It monitors the wiring configuration and solenoid operation, coordinating the electromagnetic field generation and latch control to achieve both ground fault protection and reverse wiring prevention.
2Ease of operation
If traditional latch mechanism is used, then the device is compact, but high mechanical resistance prevents easy release
Solution Approach 1:
The patent replaces the traditional mechanically-latched system with an electromechanical system using a solenoid coil. The electromagnetic force generated by the solenoid easily overcomes the frictional forces in the pivotal latch mechanism, allowing simple button-actuated release without requiring high mechanical force to overcome latch resistance.
Solution Approach 2:
The latch mechanism uses a pivotal bracket that can rotate freely with low friction. The dynamic design allows the latch to be easily moved from the engaged to disengaged position by the solenoid's electromagnetic force or by manual button pressure, providing smooth and easy operation.
3Reliability
If no end-of-life indicator is provided, then the device structure is simpler, but safety requirements are not met
Solution Approach 1:
The patent uses an LED indicator that changes color or illumination state to indicate the end-of-life status of the GFCI device. This visual signaling mechanism provides clear safety information to users without requiring complex electronic displays or multiple indicator components.
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 enhanced safety through effective reverse wiring protection and easy operation by reducing the power required to release the latch, allowing for efficient space utilization and clear indication of end-of-life, thus preventing electrical shocks and fires.
Implementation Method 1
The imbalance can produce an output voltage from the toroidal coil to trigger a semiconductor circuit that energizes a solenoid coil. The solenoid coil drives an armature to release a latch that otherwise holds a pair of movable electrical contacts against a pair of stationary electrical contacts.
Implementation Method 2
One or more toroidal coils can encircle the primary power lines to detect an imbalance in the currents in those lines. The imbalance can produce an output voltage from the toroidal coil
Implementation Method 3
The axial core of the armature seats in the vertical groove of the latch plate. One end of the first armature has a return spring
Data Source
AI summary
A ground fault circuit interrupter which comprises a main body structure, a low friction mechanical means, an electrical circuit, a low current utilizing solenoid, all of which are located in the main body structure for (1) interrupting the flow of electrical current in the interrupter when current flows from a live or neutral line to ground, (2) indicating an end-of-life condition in the interrupter, and (3) providing protection from reverse wiring of the interrupter.