Solenoidal hall effects current sensor

• US 20060290340A1
• Filed: 06/27/2005
• Published: 12/28/2006
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: Greenwich Instruments Co., Inc.
• Original Assignee: Greenwich Instruments Co., Inc.
• Inventors: Shapiro, Jonathan S.
• Granted Patent: US 7,288,928 B2
• Time in Patent Office: Days
• US Class Current: 324/117.00H
• CPC Class Codes: H05G 1/265 Measurements of current, voltage or power

Abstract

A device for measuring anode tube current or filament current in an X-ray tube, comprising a coil of wire wrapped around an insulating tube to generate a solenoidal magnetic field, one or more pieces of magnetic material and insulating material located within the tube (which magnetic elements may have their electrical potential stabilized by a resistive voltage divider), and a Hall Effect current sensor (HECS) located at the far end of the tube and insulated from the magnetic material. The output of the Hall Effects sensor is connected to an amplifier circuit, and a secondary coil of wire is used to capture the high frequency component of the magnetic signal. The secondary coil is connected to a current amplifier circuit which is followed by a high pass filter to only provide components above the cross over frequency of the hall sensor. The two signals are combined with an amplifier to provide a broad band signal that may be viewed by a current amplifier.

Claims

1. A sensor for measuring anode tube current or filament current in a high voltage device such as an X-ray tube, said sensor comprising at least one coil of wire, at least one piece of ferrous material, and a magnetic field sensor.

2. A sensor for measuring anode tube current or filament current in a high voltage device such as an X-ray tube, said sensor comprising at least one coil of wire having at least one turn, said coil being wrapped around an insulating tube, wherein said insulating tube houses at two or more pieces of magnetic material separated by an insulating material, and further including a magnetic field sensor capable of measuring a static and alternating magnetic field.

3. The sensor of claim 2, wherein said coil of wire comprises approximately 200 turns of wire.

4. The sensor of claim 2, wherein said insulating tube is composed of plastic and has an inner diameter of between ¾

inch and ⅝

inch and an outer diameter of between ⅞

inch and 1¼

inch.

5. The sensor of claim 2, wherein said insulating tube houses four pieces of magnetic material and four pieces of insulating material.

6. The sensor of claim 2, wherein said insulating material comprises cup shaped members having a diameter of approximately 0.470 inch.

7. The sensor of claim 2, wherein said magnetic material comprises a ferrous substance and include electrical contacts.

8. The sensor of claim 2, wherein said magnetic sensor comprises a Hall Effects magnetic sensor.

9. The sensor of claim 8, wherein said Hall Effects magnetic sensor is insulated from said magnetic material.

10. The sensor of claim 2, wherein retaining springs are provided to maintain contact between said magnetic material, said insulating material and said magnetic sensor.

11. The sensor of claim 2, further including a power supply for providing power to said magnetic sensor.

12. The sensor of claim 11, wherein said power supply is ±

5 volts for the magnetic sensor.

13. The sensor of claim 2, wherein an electric field having electrical potentials and magnetic potentials is generated between said pieces of magnetic material, wherein at least one resister is provided to fix said electrical potentials and magnetic potentials and make uniform the electric field between said pieces of magnetic material.

14. A sensor for detecting the presence of a high voltage signal, said sensor including a sensing circuit and means for increasing the accuracy of measurement by factoring long term drift, said means for increasing comprising means for measuring long term drift of said sensing circuit, wherein said sensing circuit includes means for establishing a value of said drift before exposure of said sensor to said signal is made using a series of electronic memories, such that the value of said saved drift would be subtracted from the value of said signal.

15. The sensor of claim 14, further including means to disable and manually adjust the said drift of said circuit.