Non-contact DC Voltage Measurement via Oscillating Sensor
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Solution Overview
Problem
Conventional voltmeters require galvanic contact for measuring DC voltage, posing safety risks and necessitating exposure of insulated wires, which is inconvenient and dangerous.
Innovation Solution
A non-contact DC voltage measurement device using a conductive sensor that capacitively couples with insulated conductors, mechanically oscillated to vary capacitance, and a control circuitry that determines DC voltage based on sensor current signals, AC reference voltage, and oscillation frequency, without requiring physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltmeters use galvanic contact to measure DC voltage, then measurement accuracy is improved, but safety risk increases and convenience deteriorates
Solution Approach 1:
The patent introduces an insulator as an intermediary between the measurement electrode and the conductor. The insulator allows capacitive coupling to occur without direct galvanic contact, enabling voltage measurement while maintaining electrical isolation and preventing shock hazard. The measurement electrode capacitively couples to the conductor through the insulator surface, creating a displacement current that can be measured without breaking the insulation barrier.
Solution Approach 2:
The patent replaces the traditional galvanic contact mechanism with a capacitive coupling mechanism. Instead of requiring direct electrical contact between the probe and conductor, the system uses the electric field between the measurement electrode and conductor through the insulator to induce a measurable current. This substitution eliminates the need for physical contact while maintaining measurement capability.
2Ease of operation
If conventional voltmeters require exposed wire or terminal for galvanic contact, then measurement function is achieved, but ease of operation deteriorates and safety risk increases
Solution Approach 1:
The insulator serves as a mediator that enables measurement on insulated conductors without requiring the insulation to be removed. By placing the measurement electrode near the insulated conductor, the electric field penetrates the insulator material and induces a capacitive current that can be measured, allowing operation on fully insulated wires.
Solution Approach 2:
The patent employs mechanical vibration or oscillation of the measurement electrode to modulate the capacitive coupling with the conductor. This vibration creates a time-varying capacitance that generates a measurable displacement current through the insulator, enhancing the signal strength and enabling detection without direct contact.
3Object-affected harmful factors
If non-contact measurement method is used with capacitive sensor, then safety is improved and convenience is improved, but measurement precision deteriorates
Solution Approach 1:
The measurement electrode is mechanically vibrated or oscillated at a specific frequency to modulate the capacitive coupling with the conductor. This vibration creates a time-varying displacement current that can be detected and processed. The oscillation amplitude and frequency are controlled to optimize the signal strength while maintaining safe operating distances, thereby improving measurement precision without compromising safety.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and adjust the measurement parameters in real-time. By detecting the displacement current generated through capacitive coupling and using feedback control, the system can compensate for variations in coupling conditions, insulator properties, and distance, thereby maintaining measurement accuracy despite the non-contact method.
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
Enables safe and accurate measurement of DC voltage in insulated conductors without galvanic contact, reducing the risk of electrical shock and allowing for convenient measurement without exposing the wire insulation.
Implementation Method 1
the conductive sensor capacitively couples with the insulated conductor
Implementation Method 2
the mechanical oscillator causes the conductive sensor to mechanically oscillate according to a mechanical oscillation amplitude and a mechanical oscillation frequency such that a distance between the conductive sensor and the insulated conductor varies periodically
Implementation Method 3
a conductive internal ground guard which at least partially surrounds the conductive sensor and is galvanically isolated from the conductive sensor, the internal ground guard sized and dimensioned to shield the conductive sensor from stray currents
Implementation Method 4
a conductive reference shield which surrounds at least a portion of the housing and is galvanically insulated from the internal ground guard, the conductive reference shield sized and dimensioned to reduce currents between the internal ground guard and an external ground
Data Source
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AI summary
Systems and methods for measuring direct current (DC) voltage of an insulated conductor (e.g., insulated wire) are provided, without requiring a galvanic connection between the conductor and a test electrode or probe. A non-contact DC voltage measurement device may include a conductive sensor that is mechanically oscillated. The insulated conductor under test serves as a first conductive element or electrode of a coupling capacitor, and the vibrating conductive sensor serves as a second conductive element or electrode of the coupling capacitor. The oscillation of the conductive sensor provides the coupling capacitor with a time-varying capacitance value. The measurement device detects current flowing through the coupling capacitor, and determines the DC voltage in the insulated conductor using the detected current and the time-varying capacitance. The determined DC voltage may be output to a display or transmitted to an external system via a wired or wireless connection.