Absence-of-Voltage Detector With Isolated FM Mixing
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Solution Overview
Problem
Existing voltage detection methods for electrical equipment pose safety hazards due to exposure to energized circuits during testing, and there is a need for a reliable, permanently installed device to verify the absence of voltage safely and accurately.
Innovation Solution
A voltage indicator utilizing frequency modulation (FM) techniques with an isolation circuit, redundant paths, and diagnostic validation to ensure accurate detection of voltage absence, incorporating an FM modulator, reference oscillator, mixer, and envelope detector to convert RF signals to voltage levels, with fail-safe mechanisms against component drift and connectivity verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a portable voltmeter or multimeter is used to test for voltage absence, then the detection capability is provided, but workers are exposed to energized circuits and safety hazards occur
Solution Approach 1:
The patent introduces a permanently installed voltage detector as an intermediary device between the worker and the energized circuit. This detector is pre-installed in the electrical compartment and can be activated remotely or automatically to detect voltage presence before workers approach, eliminating direct exposure to live circuits while maintaining reliable detection capability
Solution Approach 2:
The system performs voltage detection in advance before workers begin their tasks. By having the detector already in place and capable of remote activation, the voltage status is verified beforehand, allowing workers to proceed only when confirmed safe, thus preventing exposure to energized circuits
2Object-affected harmful factors
If a permanently installed voltage detector is used, then worker safety is improved, but device complexity increases
Solution Approach 1:
The permanently installed detector serves multiple functions: voltage detection, status indication, and potential integration with safety interlock systems. By designing a multi-functional device, the patent reduces the need for separate systems while maintaining comprehensive safety coverage
Solution Approach 2:
The detector is designed to be self-contained with internal power sources and automatic operation capabilities. It can autonomously detect voltage conditions and provide indications without requiring constant external intervention, reducing operational complexity while enhancing safety
3Measurement precision
If frequency modulation techniques are used for voltage detection, then detection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs frequency modulation as a detection parameter change technique. By modulating the detector's operating frequency based on voltage presence, the system achieves high detection accuracy and immunity to electrical noise while using well-established FM circuitry that balances precision with manufacturability
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
Provides a safe and reliable method to verify voltage absence, reducing safety risks and ensuring high confidence in detection accuracy through fail-safe mechanisms and diagnostic validation.
Implementation Method 1
A permanently installed device that can detect the presence of and verify the absence of primary (single- or multi-phase AC or DC) voltage and positively indicate the status of voltage
Implementation Method 2
the output of the mixer is the difference of the two signals
Data Source
AI summary
An absence of voltage indicator has an isolation circuit, an FM modulator attached to the isolation circuit, a reference oscillator, and a mixer attached to the reference oscillator and the FM modulator, wherein the output of the mixer is the difference of the two signals. In one embodiment, the FM modulator includes a variable capacitor which varies in response to a voltage in parallel to a fixed capacitor and an inductor in parallel to the capacitors.