Non-contact current measurement system

Patent metadata

Field	Value
Publication number	US-2020191836-A1
Application number	US-202016799686-A
Country	US
Kind code	A1
Filing date	Feb 24, 2020
Priority date	Nov 11, 2016
Publication date	Jun 18, 2020
Grant date	—

Abstract

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.

First claim

1 . A current measurement system, comprising:
an adjustable clamp assembly which selectively clamps and locates an insulated wire at a position within the adjustable clamp assembly; a position feedback sensor that, in operation, autonomously senses the position of the insulated wire and generates a position feedback sensor signal indicative of the sensed position of the insulated wire clamped within the adjustable clamp assembly; 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 clamped within the adjustable clamp assembly; and control circuitry communicatively coupled to the position feedback sensor and the magnetic field sensor, wherein in operation, the control circuitry:
receives the position feedback sensor signal from the position feedback sensor;
receives the magnetic field sensor signal from the magnetic field sensor; and
determines at least one characteristic of the current flowing through the insulated wire based at least in part on the received position feedback sensor signal and the magnetic field sensor signal.

2 . The current measurement system of claim 1 wherein the adjustable clamp assembly comprises a first clamp surface and a second clamp surface, wherein the second clamp surface faces the first clamp surface, and at least one of the first and second clamp surfaces is movable in a direction toward and away from the other of the first and second clamp surfaces to selectively clamp the insulated wire between the first and second clamp surfaces.

3 . The current measurement system of claim 2 wherein the first clamp surface comprises a front end surface of a front end of a housing of the current measurement system, and the second clamp surface is disposed on a clamp member that is selectively movable with respect to the front end surface.

4 . The current measurement system of claim 3 wherein the magnetic field sensor is positioned proximate the front end surface of the front end of the housing.

5 . The current measurement system of claim 1 wherein the adjustable clamp assembly comprises a slider clamp assembly, and the position feedback sensor comprises a linear position feedback sensor that generates a position feedback signal indicative of a linear position of the slider clamp assembly.

6 . The current measurement system of claim 1 wherein the adjustable clamp assembly comprises a first clamp portion having a first clamp surface and a second clamp portion having a second clamp surface that faces the first clamp surface, and a biasing member biases the first clamp portion toward the second clamp portion.

7 . The current measurement system of claim 6 wherein at least one of the first clamp surface and the second clamp surface operates as a shield for the magnetic field sensor.

8 . The current measurement system of claim 1 wherein the at least one characteristic of the current flowing through the insulated wire comprises a magnitude of the current flowing through the insulated wire.

9 . The current measurement system of claim 1 wherein the position feedback sensor comprises a resistive sensor, a magneto-resistive sensor, a Hall Effect sensor, a capacitive sensor, an inductive sensor, or an optical sensor.

10 . The current measurement system of claim 1 , further comprising:
a reference signal type sensor that, in operation, senses a reference signal in the insulated wire without galvanically contacting the insulated wire, wherein the control circuitry receives the reference signal and determines the at least one characteristic of the current flowing through the insulated wire based at least in part on the received reference signal.

11 . The current measurement system of claim 10 wherein the control circuitry further determines at least one physical dimension of a conductor inside the insulated wire based at least in part on the received reference signal, wherein the at least one physical dimension is indicative of a distance between the conductor and the magnetic field sensor.

12 . The current measurement system of claim 10 wherein the control circuitry further determines at least one physical dimension of a conductor inside the insulated wire based at least in part on the received reference signal and the received position feedback sensor signal.

13 . A method of measuring current in an insulated wire without galvanically contacting a conductor in the insulated wire, the method comprising:
clamping, via an adjustable clamp assembly, the insulated wire between first and second clamp surfaces; autonomously determining a position of the insulated wire clamped between the first and second clamp surfaces; sensing, via a magnetic field sensor positioned proximate the insulated wire clamped between the first and second clamp surfaces, a magnetic field generated by the current flowing through the insulated wire; and determining at least one characteristic of the current flowing through the insulated wire based at least in part on the determined position of the insulated wire clamped between the first and second clamp surfaces and the sensed magnetic field generated by the current flowing through the insulated wire.

14 . The method of claim 13 wherein the first clamp surface comprises a front end surface of a front end of a housing and the second clamp surface comprises a surface of a clamp member of the adjustable clamp assembly that is movable with respect to the front end surface, and clamping the insulated wire between the first and second clamp surfaces comprises clamping the insulated wire between the front end surface and the surface of the clamp member.

15 . The method of claim 14 wherein sensing the magnetic field generated by the current flowing through the insulated wire comprises sensing the magnetic field via the magnetic field sensor, and the magnetic field sensor is positioned proximate the front end surface of the front end of the housing.

16 . The method of claim 13 wherein clamping the insulated wire between the first and second clamp surfaces comprises clamping the insulated wire between first and second clamp surfaces of a slider clamp assembly.

17 . The method of claim 13 wherein the first clamp surface is positioned on a first clamp portion and the second clamp surface is positioned on a second clamp portion, and the method further comprises biasing the first clamp portion toward the second clamp portion.

18 . The method of claim 13 wherein determining the at least one characteristic of the current flowing through the insulated wire comprises determining a magnitude of the current flowing through the insulated wire.

19 . The method of claim 13 , further comprising:
sensing, via a reference signal type sensor positioned in a housing, a reference signal in the insulated wire without galvanically contacting the insulated wire; and determining, via the control circuitry, the at least one characteristic of the current flowing through the insulated wire based at least in part on the sensed reference signal.

20 . The method of claim 19 , further determining, via the control circuitry, at least one physical dimension of a conductor inside the insulated wire based at least in part on the received reference signal.

21 . The method of claim 19 , further determining, via the control circuitry, at least one physical dimension of

Assignees

• Fluke Corp

Inventors

• Rodriguez Ricardo
• Epperson David L
• Steuer Ronald
• Worones Jeffrey

Classifications

• G01R19/0046

  characterised by a specific application or detail not covered by any other subgroup of G01R19/00 · CPC title

• G01R15/207 Primary

  Constructional details independent of the type of device used · CPC title

• G01R1/22 Primary

  Tong testers acting as secondary windings of current transformers · CPC title

• G01R15/148

  involving the measuring of a magnetic field or electric field (G01R15/18, G01R15/20, G01R15/24, G01R15/26 take precedence) · CPC title

• G01R15/146

  Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop (if no voltage isolation is involved G01R1/203 or G01R19/0092) · CPC title