Non-contact current and voltage sensor having detachable housing incorporating multiple ferrite cylinder portions

Patent metadata

Field	Value
Publication number	US-9322855-B2
Application number	US-201414319389-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Feb 9, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing formed from two portions that mechanically close around the wire and that contain the current and voltage sensors. The current sensor is a ferrite cylinder formed from at least three portions that form the cylinder when the sensor is closed around the wire with a hall effect sensor disposed in a gap between two of the ferrite portions along the circumference to measure current. A capacitive plate or wire is disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

First claim

What is claimed is:

1. A sensor for sensing an electric potential on a wire of a power distribution system and a current passing through the wire, the sensor comprising:
a housing for detachably coupling the sensor to the wire, wherein the housing comprises two portions mechanically coupled together such that the housing is closed around the wire when the sensor is coupled to the wire;
a current sensing device integrated in the housing for providing a first output indicative of the current passing through the wire, the current sensing device including at least three ferrite cylinder portions disposed within corresponding ones of the housing portions, wherein when the housing is coupled to the wire, the wire passes through a central void defined by the ferrite cylinder portions extending through a central axis thereof, and wherein a gap is defined along a circumference of a cylinder formed by the ferrite cylinder portions, and wherein the current sensing device further comprises a semiconductor magnetic field sensor disposed within the gap, wherein the gap is located at an circumferential position substantially rotated away from the junctions of the housing portions, whereby the semiconductor magnetic field sensor is configured to be coupled to an external circuit without interfering with the operation of the housing, wherein the first output is an output of the semiconductor magnetic field sensor; and
a voltage sensing device integrated in the housing for providing a second output indicative of the electric potential on the wire, wherein the voltage sensing device and the current sensing device do not make electrical contact with the wire.

2. The sensor of claim 1 , wherein the housing portions are rotatably coupled along an axis parallel to the central axis of the ferrite cylinder portions and disposed at a circumference of the housing, whereby the housing forms a clamshell that is configured to be secured around the wire when the wire is disposed within the central void defined by the ferrite cylinder portions.

3. The sensor of claim 1 , wherein the voltage sensing device comprises at least one metal cylinder portion disposed within the housing and axially displaced from the current sensing device along a length of the housing, wherein the second output is a voltage of an electrical connection to the at least one metal cylinder portion.

4. The sensor of claim 1 , wherein the voltage sensing device comprises at least one metal cylinder portion disposed within the central void and through which the wire is disposed when the housing is coupled to the wire, wherein the second output is a voltage of an electrical connection to the at least one metal cylinder portion.

5. The sensor of claim 4 , wherein the at least one metal cylinder portion is a metal layer deposited on or affixed to at least one of the ferrite cylinder portions.

6. The sensor of claim 1 , wherein the voltage sensing device comprises a second wire inserted in parallel with the wire and disposed within the central void, wherein the second output is a voltage of an electrical connection to the second wire.

Assignees

• IBM

Inventors

• Carpenter Gary D
• El-Essawy Wael
• Ferreira Alexandre Peixoto
• Keller Thomas Walter
• Rubio Juan C
• Schappert Michael A

Classifications

• G01R15/142

  Arrangements for simultaneous measurements of several parameters employing techniques covered by groups G01R15/14 - G01R15/26 · CPC title

• G01R33/072

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R33/02

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01R1/22 Primary

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

• G01R21/06 Primary

  by measuring current and voltage (G01R21/08 - G01R21/133 take precedence) · CPC title