Multifunction Circuit Breaker Single Test Button
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Solution Overview
Problem
Existing multifunction circuit breaker devices require additional hardware and are complex due to separate test inputs for arc fault and ground fault self-tests, making it difficult to distinguish between simulated and actual ground faults, leading to potential incorrect user feedback.
Innovation Solution
A method and system using a single test input to initiate both self-test sequences, with a microcontroller that distinguishes between simulated and actual ground faults by adjusting detection thresholds, allowing the device to delay tripping until all self-tests pass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate test inputs are used for arc fault and ground fault self-tests, then each self-test can be independently initiated, but the device complexity and hardware requirements increase
Solution Approach 1:
The patent combines multiple test inputs into a single test button that can initiate both arc fault and ground fault self-tests. The single button generates test signals that are routed to both test circuits, eliminating the need for separate buttons while maintaining the ability to independently test each fault type.
Solution Approach 2:
The single test button is designed to perform multiple functions: it can initiate arc fault self-tests, ground fault self-tests, or both simultaneously. The button is connected to a control circuit that distributes test signals to different test circuits based on the testing requirements.
2Device complexity
If a single test button with multiple positions is used, then hardware components are reduced, but design complexity and manufacturing costs increase
Solution Approach 1:
Instead of using a single button with multiple positions, the patent merges the functionality of multiple buttons into a single button connected to a control circuit. This approach reduces mechanical complexity while avoiding the manufacturing challenges of multi-position buttons.
Solution Approach 2:
The patent replaces the mechanical complexity of a multi-position button with an electrical control system. The single button generates electrical signals that are processed by a microcontroller or control circuit to initiate different test sequences, eliminating the need for mechanical position detection.
3Reliability
If the supervisory circuit introduces current at least 6 mA RMS to simulate ground fault, then ground fault detection capability is tested, but the device trips immediately making it impossible to distinguish from actual ground faults
Solution Approach 1:
The patent introduces a test mode intermediary state between normal operation and tripping. When the test button is activated, the system enters a test mode where ground fault tripping is temporarily inhibited. This allows the supervisory circuit to inject test current and observe the ground fault detection response without causing an immediate trip, preserving test status information.
Solution Approach 2:
The patent performs preliminary action by setting the device into test mode before injecting the ground fault test current. The control circuit预先 configures the tripping threshold or disables tripping during test mode, allowing the test current to be injected and the detection circuitry to be verified without causing an unwanted trip.
4Reliability
If the device trips upon successful ground fault self-test, then ground fault detection is confirmed, but users may receive incorrect feedback that all self-tests passed
Solution Approach 1:
The patent implements comprehensive feedback mechanisms that provide users with clear information about the status of each self-test sequence. LEDs or display elements indicate whether arc fault testing passed, ground fault testing passed, or if the device tripped during testing. This feedback system ensures users receive accurate information about which specific tests succeeded or failed.
Solution Approach 2:
The patent uses preliminary action by inhibiting the trip function during test mode, allowing all self-test sequences to complete before any tripping occurs. This ensures that users can observe the completion status of each test sequence and receive accurate feedback about the overall test results rather than receiving premature tripping signals.
Data Source
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AI summary
Method and system for implementing multiple user-initiated self-test sequences in a multifunction circuit breaker device uses a single test input to initiate both arc fault and ground fault testing while at the same time allowing the multifunction circuit breaker device to continue detecting actual arc faults and ground faults in near real time. Having one test input for multiple self-test sequences significantly reduces the number of mechanical and electrical components required by the circuit breaker device. The multifunction circuit breaker device also distinguishes between a simulated ground fault and an actual ground fault and avoids automatically tripping upon successful completion of the ground fault self-test sequence unless and until all self-test sequences have passed. In this way, users are not given a potentially incorrect indication that the multifunction circuit breaker device is working properly.