Flexible current and voltage sensor

• US 9,007,077 B2
• Filed: 08/28/2012
• Issued: 04/14/2015
• Est. Priority Date: 08/28/2012
• Status: Active Grant

• Current Assignee: Terrace Licensing LLC (IP Edge LLC)
• Original Assignee: International Business Machines Corporation
• Inventors: El-Essawy, Wael, Ferreira, Alexandre Peixoto, Keller, Thomas Walter, Rajamani, Karthick, Rubio, Juan C., Schappert, Michael A.
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): LE, SON T
• Application Number:
  US13/596,658
• Publication Number:
  US 20140062459A1
• Time in Patent Office: 959 Days
• Field of Search: 323/713, 323244-252, 323/260, 323/344, 323/127, 323/117.R, 323/117.H, 324/713, 324244-252, 324/260, 324/344, 324/127, 324/117.R, 324/117.H
• US Class Current: 324/713
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 15/205 using magneto-resistance devices, e.g. field plates
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used

Abstract

A flexible current and voltage sensor provides ease of installation of a current sensor, and optionally a voltage sensor in application such as AC branch circuit wire measurements, which may require installation in dense wiring conditions and/or in live panels where insulating gloves must be worn. The sensor includes at least one flexible ferromagnetic strip that is affixed to a current sensing device at a first end. The second end is secured to the other side of the current sensing device or to another flexible ferromagnetic strip extending from the other side of the current sensing device to form a loop providing a closed pathway for magnetic flux. A voltage sensor may be provided by metal foil affixed to the inside of the flexible ferromagnetic strip. A clamp body, which can be a spring loaded handle operated clamp or a locking fastener, can secure the ferromagnetic strip around the wire.

Claims

1. A sensor for sensing a current passing through a wire of a power distribution system, the sensor comprising:

a current sensing device for providing a first output indicative of the current passing through the wire; and

a flexible ferromagnetic strip having the current sensing device affixed at an end thereof for forming a closed pathway for magnetic flux when the sensor is coupled to the wire, wherein a first side of the current sensing device is affixed to a first end of the flexible ferromagnetic strip, and wherein a second end of the ferromagnetic strip abuts a second side of the current sensing device to form the closed pathway through the current sensing device when the sensor is coupled to the wire, further comprising at least one securing material affixed to one of the second end of the ferromagnetic strip or the second side of the current sensing device to secure the second end of the ferromagnetic strip to the second side of the current sensing device.

2. The sensor of claim 1, further comprising a voltage sensing device affixed to the flexible ferromagnetic strip for providing a second output indicative of the electric potential on the wire, wherein the voltage sensing device does not make electrical contact with the wire.

3. The sensor of claim 2, wherein the voltage sensing device comprises a metal foil having substantially a same width and a same length as the flexible ferromagnetic strip.

4. The sensor of claim 1, wherein a first side of the current sensing device is affixed to an inside surface at the first end of the flexible ferromagnetic strip, and wherein an opposing outside surface at the second end of the ferromagnetic strip abuts a second side of the current sensing device to form the closed pathway through the current sensing device.

5. The sensor of claim 4, wherein the at least one securing material is affixed to one of the inside surface at the second end of the ferromagnetic strip or the second side of the current sensing device to secure the outside surface at the second end of the ferromagnetic strip to the second side of the current sensing device.

6. A method of sensing a current passing through a wire of a power distribution system, the method comprising:

securing a flexible ferromagnetic strip having a current sensing device affixed at an end thereof around the wire to form a closed pathway for magnetic flux including the current sensing device, wherein the securing secures a single flexible ferromagnetic strip having a first side of the current sensing device affixed at a first end thereof, and second side of the current sensing device abutted to the ferromagnetic strip at a second end thereof to form the closed pathway through the current sensing device when the sensor is coupled to the wire, wherein the securing is performed by at least one securing material affixed at one of the second end of the first ferromagnetic strip or the second end of the second ferromagnetic strip to secure the second end of the first ferromagnetic strip at the second end of the second ferromagnetic strip; and

measuring an output of the current sensing device to provide an indication of the instantaneous value of the current.

7. The method of claim 6, wherein the securing further secures a voltage sensing device affixed to the flexible ferromagnetic strip for providing a second output indicative of the electric potential on the wire, wherein the voltage sensing device does not make electrical contact with the wire.

8. The method of claim 7, wherein the securing secures a voltage sensing device comprising a metal foil having substantially a same width and a same length as the flexible ferromagnetic strip.

9. A sensor for sensing a current passing through a wire of a power distribution system, the sensor comprising:

a current sensing device for providing a first output indicative of the current passing through the wire;

a sensor clamp body for securing the sensor to the wire, wherein the flexible ferromagnetic strip and the current sensing device are disposed within the sensor clamp body;

a flexible ferromagnetic strip having the current sensing device affixed at an end thereof for forming a closed pathway for magnetic flux when the sensor is coupled to the wire;

a pair of handles disposed at a proximal end of the sensor clamp body; and

a hinge mechanism, and wherein the flexible ferromagnetic strip is disposed within an aperture formed at a distal end of the sensor clamp body, wherein the pair of handles, when compressed together, open the aperture to permit insertion of the wire, wherein the hinge mechanism includes a restoring spring to close the aperture around the wire when the pair of handles is released, wherein the flexible strip is disposed along an inside circumference of the aperture and secured to the sensor clamp body, and wherein when the aperture is open, the flexible ferromagnetic strip separates only at a distal end of the aperture, whereby the flexible ferromagnetic strip flexes at a proximal end of the aperture when the pair of handles is compressed together or released.