Patent US3885212A successfully refreshed from Google Patents.
US3885212A
Expired / Lapsed
US
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Sector flux null current measuring apparatus and method
Assignee: Sanwa Business Credit Corp
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Filing: 1973-04-05
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Granted: 1975-05-20
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Expires: 1993-04-05
Abstract
Abstract A high current measuring apparatus and method is disclosed. In very high current applications, such as in the manufacture of chlorine gas, a measurable field is established around a currentcarrying bus. A field-measuring device, such as a Hall device, is located within the field surrounding the current-carrying bus. This field-measuring device is disposed between two fieldconcentrating elements which concentrate the field passing through the device. Electrical signals from the field-measuring device are amplified by a high-gain amplifier whose output is applied to coils wound around the field-concentrating elements. The current in these coils is operative to reduce or to null the field passing through the field-measuring device. The steadystate current in these coils is proportional to the current in the bus. By passing a known current through the bus or by measuring an unknown current with another already calibrated current-measuring device, the measured coil current can be directly calibrated to bus current. After calibration, the previously calibrated current-measuring device is removed.
Inventors
- 👤 William L Herbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:07
CPC Classifications
G; G01; G01R; G01R15/00; G01R15/14; G01R15/20; G01R15/202
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
A method of monitoring current in one of a plurality of adjacent buses which are carrying high amperage currents of unknowwn magnitudes and which are producing high extraneous fields of unknown magnitude around the bus to be monitored comprising the steps of: locating a field-sensing element between two unconnected non-annular magnetic field-concentrating members; fixedly positioning said field-sensing element and said magnetic field-concentrating members in the field produced by the current in the bus being monitored; connecting said field-sensing element to a current-indicating apparatus; temporarily applying a current-measuring device to the bus; calibrating saud current-indicating apparatus against the current measured by said temporarily applied current-measuring device; and removed said temporarily applied current-measuring device.
Claim 2
Independent Claim
112 words
A method of monitoring current in one of a plurality of adjacent buses which are carrying high amperage currents of unknowwn magnitudes and which are producing high extraneous fields of unknown magnitude around the bus to be monitored comprising the steps of: locating a field-sensing element between two unconnected non-annular magnetic field-concentrating members; fixedly positioning said field-sensing element and said magnetic field-concentrating members in the field produced by the current in the bus being monitored; connecting said field-sensing element to a current-indicating apparatus; temporarily applying a current-measuring device to the bus; calibrating saud current-indicating apparatus against the current measured by said temporarily applied current-measuring device; and removed said temporarily applied current-measuring device.
Claim 3
Dependent Claim
59 words
The method of monitoring current of claim 1 wherein the step of fixedly positioning the field-sensing element additionally includes locating the field-sensing element adjacent the current-carrying bus being monitored at a point where the direction of the field created by the current being monitored is substantially normal to the direction of the field produced by other nearby current-carrying buses.
Claim 4
Dependent Claim
53 words
The method of monitoring current of claim 1 wherein the step of fixedly positioning the field-sensing element additionally includes locating the field-sensing element adjacent the current-carrying bus being monitored at a point where the direction of the field created by current being monitored is substantially normal to the direction of other extraneous fields.
Claim 5
Independent Claim
204 words
An apparatus for measuring current in a bus comprising, in combination: a field-sensing element for sensing the field at one point in space and producing a signal having a magnitude proportional to the field which passes therethrough and produced by the current being measured, said field-sensing element being fixedly located in the field produced by the current being measured at a point where fields produced by other conducting buses are substantially perpendicular to the field produced by the current being measured; a pair of unconnected non-annular field-concentrating members located on opposite sides of said field-sensing means for concentrating only a sector of the field produced by the current being measured; an electrical conducting coil wound around said fieldconcentrating members, said coil surrounding said field-sensing element and field-concentrating members on both sides of said field-sensing element; an amplifier means electrically responsive to said signal from said field-sensing element for producing an amplified signal at the output of said amplifier; means for connecting said amplifier output to said coil to produce a field in said field-concentrating members in a direction opposite the field produced by the current being measured; and means to measure said amplified signal, the magnitude thereof being proportional to the current being measured.
Claim 6
Independent Claim
204 words
An apparatus for measuring current in a bus comprising, in combination: a field-sensing element for sensing the field at one point in space and producing a signal having a magnitude proportional to the field which passes therethrough and produced by the current being measured, said field-sensing element being fixedly located in the field produced by the current being measured at a point where fields produced by other conducting buses are substantially perpendicular to the field produced by the current being measured; a pair of unconnected non-annular field-concentrating members located on opposite sides of said field-sensing means for concentrating only a sector of the field produced by the current being measured; an electrical conducting coil wound around said fieldconcentrating members, said coil surrounding said field-sensing element and field-concentrating members on both sides of said field-sensing element; an amplifier means electrically responsive to said signal from said field-sensing element for producing an amplified signal at the output of said amplifier; means for connecting said amplifier output to said coil to produce a field in said field-concentrating members in a direction opposite the field produced by the current being measured; and means to measure said amplified signal, the magnitude thereof being proportional to the current being measured.
Claim 7
Independent Claim
147 words
A method of monitoring current in one of a plurality of adjacent buses which are carrying high amperage currents of unknown magnitudes and which are pRoducing high extraneous fields of unknown magnitude around the bus to be monitored comprising the steps of: locating a field-sensing element between two unconnected non-annular magnetic field-concentrating members; fixedly positioning said field-sensing element and said magnetic field-concentrating members in the field produced by the current in the bus; connecting said field-sensing element to an amplifier for producing a signal, said signal being used to generate a field in a direction opposite to the direction of the field at the field-sensing element generated by the current in the bus being monitored; measuring said signal; temporarily applying a current-measuring device to the bus; calibrating said measured signal against the current measured by said temporarily applied current-measuring device; and removing said temporarily applied current-measuring device.
Claim 8
Independent Claim
147 words
A method of monitoring current in one of a plurality of adjacent buses which are carrying high amperage currents of unknown magnitudes and which are pRoducing high extraneous fields of unknown magnitude around the bus to be monitored comprising the steps of: locating a field-sensing element between two unconnected non-annular magnetic field-concentrating members; fixedly positioning said field-sensing element and said magnetic field-concentrating members in the field produced by the current in the bus; connecting said field-sensing element to an amplifier for producing a signal, said signal being used to generate a field in a direction opposite to the direction of the field at the field-sensing element generated by the current in the bus being monitored; measuring said signal; temporarily applying a current-measuring device to the bus; calibrating said measured signal against the current measured by said temporarily applied current-measuring device; and removing said temporarily applied current-measuring device.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |