Non-contact Current Measurement System Using Magnetic Field Sensor
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Solution Overview
Problem
Conventional ammeters and multimeters require galvanic contact to measure AC current, which can be dangerous and limits measurement to a few amperes due to internal current shunts, and often necessitate breaking circuits or exposing wires, posing safety risks.
Innovation Solution
A non-contact current measurement system using an adjustable clamp assembly with a magnetic field sensor to detect current without physical contact, determining current characteristics based on position feedback and magnetic field signals, allowing for safe measurement of AC current in insulated wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ammeters use internal current shunts to measure current, then measurement capability is provided, but the device is limited to a few amperes maximum and requires breaking the current-carrying conductor
Solution Approach 1:
The patent replaces the mechanical/electrical contact-based current shunt system with a magnetic field sensing system. The magnetic field sensor detects the magnetic field generated by current flow in the conductor without requiring physical contact or circuit breaking, thereby extending measurement range beyond a few amperes and maintaining circuit continuity.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the current-carrying conductor and the measurement device. The magnetic field sensor measures the magnetic field generated by the current, which serves as an indirect mediator to determine current magnitude without direct electrical contact, thus avoiding the limitations of internal current shunts.
2Measurement precision
If measurement probes are brought into galvanic contact with conductors, then current measurement is achieved, but safety risks of shock or electrocution increase
Solution Approach 1:
The patent replaces direct galvanic contact with magnetic field sensing. The magnetic field sensor measures the magnetic field surrounding the conductor without touching it, eliminating the safety risks associated with probe contact while maintaining measurement capability through non-contact detection.
Solution Approach 2:
The magnetic field serves as a safe intermediary that carries measurement information from the conductor to the sensor without requiring dangerous physical contact. This intermediary approach allows accurate measurement while keeping the measurement device isolated from electrical hazards.
3Measurement precision
If internal current shunts are used in multimeters, then current measurement is possible, but the multimeter requires protective fuses and is limited in current capacity
Solution Approach 1:
The patent substitutes the internal current shunt architecture with external magnetic field sensing. This eliminates the need for protective fuses and current capacity limitations inherent in shunt-based designs, as the magnetic field sensor has no direct current path and can measure much higher currents without damage.
Solution Approach 2:
By using the magnetic field as an intermediary measurement medium, the system avoids direct current flow through the measurement device. This eliminates the need for current-carrying components like shunts and fuses, thereby removing current capacity limitations and protective requirements while maintaining measurement functionality.
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 AC current in insulated wires without breaking the circuit or exposing wires, overcoming safety risks and limitations of conventional methods, and allowing for higher current measurement capabilities.
Implementation Method 1
a magnetic field sensor positioned proximate the adjustable clamp assembly, wherein in operation the magnetic field sensor generates a magnetic field sensor signal that is indicative of at least one characteristic of a current flowing through the insulated wire
Implementation Method 2
a position feedback sensor that, in operation, generates a position feedback sensor signal indicative of a diameter of the insulated wire clamped in the adjustable clamp assembly
Data Source
AI summary
Systems and methods provide a non-contact current measurement system which operates to measure alternating current flowing through an insulated wire without requiring galvanic contact with the insulated wire. The measurement system may include a magnetic field sensor that is selectively positionable proximate an insulated wire under test. In operation the magnetic field sensor detects a magnetic field generated by the current flowing in the insulated wire. Using an adjustable clamp assembly, the measurement system provides control over the mechanical positioning of the insulated wire relative to the magnetic field sensor to ensure consistent measurements. The non-contact current measurement system may determine information relating to the physical dimensions (e.g., diameter) of the insulated wire. Using the detected magnetic field, the known mechanical positioning, and the determined information relating to the physical dimensions of the insulated wire, the measurement system accurately determines the magnitude of the current flowing through the insulated wire without galvanic contact.