MRS current sensor
First Claim
1. A current sensor for measuring current flow in an electrical conductor, said sensor comprising:
- a magnetic flux concentrator comprising a magnetic pole structure substantially encircling the cross-sectional shape of said conductor and including two magnetic pole portions spaced to provide a magnetic sensing region therebetween whereby electrical current flowing in said conductor will induce a magnetic field within said region;
means disposed to measure a component of magnetic field intensity along a principal axis within said sensing region and operative to generate an output signal as a function thereof; and
means operative to generate a component of magnetic field intensity within said region along an axis offset from said principal axis, said offset component having a characteristic magnitude substantially unaffected by flow of current in said conductor.
1 Assignment
0 Petitions
Accused Products
Abstract
A current sensor (10) comprising spaced pole pieces (62, 64) and a magnetic shunt (80) bridging the pole pieces within an insulating housing assembly (12) which also contains a magnetoresistive transducer (90) and electronic circuitry (16) for sensing magnetic field intensity between the pole pieces and relating that intensity as electric signals provided at terminals (26) at the exterior of the housing. The transducer senses magnetic field intensity along a principal axis (88). Permanent magnets (94, 96) or induction coils (276, 278) are provided to establish a biasing component of magnetic field intensity along an axis (98) substantially normal to the principal axis to improve sensor sensitivity, range of operation and immunity to current overload.
31 Citations
28 Claims
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1. A current sensor for measuring current flow in an electrical conductor, said sensor comprising:
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a magnetic flux concentrator comprising a magnetic pole structure substantially encircling the cross-sectional shape of said conductor and including two magnetic pole portions spaced to provide a magnetic sensing region therebetween whereby electrical current flowing in said conductor will induce a magnetic field within said region; means disposed to measure a component of magnetic field intensity along a principal axis within said sensing region and operative to generate an output signal as a function thereof; and means operative to generate a component of magnetic field intensity within said region along an axis offset from said principal axis, said offset component having a characteristic magnitude substantially unaffected by flow of current in said conductor. - View Dependent Claims (24, 25)
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2. A current sensor for measuring current flow in an electrical conductor, said sensor comprising:
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an insulated housing; a magnetic flux concentrator in said housing comprising a magnetic pole structure substantially encircling the cross-sectional shape of said conductor in spaced relation thereto and including two magnetic pole portions spaced to provide a magnetic sensing region therebetween whereby electrical current flowing in said conductor will induce a magnetic field within said region; magnetoresistive means disposed to measure a component of magnetic field intensity along a principal axis within said sensing region and operative to generate an electrical signal as a function thereof; means in-circuit with said magnetoresistive means operative to generate an output signal as a function of said electrical signal; and means operative to generate a component of magnetic field intensity within said region along an axis offset from said principal axis, said offset component having a characteristic magnitude substantially unaffected by flow of current in said conductor. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 26)
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23. A current sensor for measuring current flow at a predetermined location within an elongated electrical conductor, said sensor comprising:
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an insulated housing defining a passageway therethrough for receiving said conductor; magnetic flux concentrator in said housing comprising two generally C-shaped magnetic pole pieces facing each other to define a conductor receiving cavity therebetween and including a first complementary opposed pair of pole portions spaced by a gap dimension Gr and a second complementary opposed pair of pole portions spaced by a gap dimension Gc, said first pair of pole portions providing a magnetic sensing region therebetween whereby electrical current flowing to said predetermined location within said conductor will induce a magnetic field within said region, said flux concentrator further comprising a magnetic shunt formed of material having a characteristic permeability equal to or exceeding the characteristic permeability of material forming said pole pieces, said shunt substantially bridging said first pair of pole portions and defining an effective gap dimension Gs therewith, wherein Gs ≦
Gc ≦
Gr, whereby said shunt is operative to divert a substantial portion of the flux within said concentrator from said sensing region;magnetoresistive means disposed within said magnetic sensing region to measure a component of magnetic field intensity along a principal axis within said sensing region and operative to generate an electrical signal as a function thereof; circuit means operative to generate at least one output signal representative of sensed current in said conductor in response to said electrical signal; and means operative to generate a component of magnetic field intensity within said region along an axis substantially normal to said principal axis, said offset component having a substantially constant magnitude unaffected by flow of current in said conductor. - View Dependent Claims (27)
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28. The current sensor for measuring current flow in a electrical conductor, said sensor comprising:
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means operative to define a magnetic sensing region proximate said conductor whereby electrical current flowing in said conductor will induce a magnetic field within said region; means disposed to measure a component of magnetic field intensity along a principal axis within said sensing region and operative to generate an output signal as a function thereof, said component measurement means comprising a plurality of geometrically offset magnetoresistive elements electrically interconnected in a bridge configuration; and means operative to generate a component of magnetic field intensity within said region along an axis offset from said principal axis, said offset component having a characteristic magnitude substantially unaffected by flow of current in said conductor.
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Specification