PRECISION, TEMPERATURE-COMPENSATED, SHIELDED CURRENT MEASUREMENT DEVICE
First Claim
1. An electric current measuring device of the type using a coil, comprising;
- a core;
a conductive coil wound about the core, forming a first winding in a first direction and a second winding constituting a return winding; and
an electrostatic shield around the core, outside of the coil, wherein the electrostatic shield comprises a cup portion and a lid portion, each portion being of electrically conductive material.
1 Assignment
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Accused Products
Abstract
A current measurement device using a Rogowski coil having a generally toroidal-shaped core with a first winding in one direction and a second winding forming a return loop. The coil is positioned within a two-piece electrostatic shield. A first piece of the electrostatic shield is a partially donut-shaped member having a U-shaped cross-section. The coil is positioned in the donut-shaped member and covered by an encapsulating material. The first piece includes a slit through the cross-section thereof to prevent an electrical loop around the perimeter thereof. The second piece of the electrostatic shield is flat and has a donut-shaped configuration. The second piece is configured with inside and outside peripheral edges such that only one or none of the inside/outside edges contact the first piece. The second piece also has a cross-sectional slit which is in registry with the slit in the first piece.
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Citations
21 Claims
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1. An electric current measuring device of the type using a coil, comprising;
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a core; a conductive coil wound about the core, forming a first winding in a first direction and a second winding constituting a return winding; and an electrostatic shield around the core, outside of the coil, wherein the electrostatic shield comprises a cup portion and a lid portion, each portion being of electrically conductive material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An electrostatic shield for a generally toroidal-shaped coil comprising:
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a partially donut-shaped lower member, the lower member comprising an electrically-conducting, non-magnetic material, the lower member having a slit through a cross-section thereof to prevent an electrical loop along a perimeter thereof; and a flat upper lid member comprising an electrically-conductive, non-magnetic material configured to fit on top of and to cooperate with the lower member to provide electrostatic shielding for a coil positioned in a volume therebetween, the lid member being donut-shaped with an inner peripheral edge and an outer peripheral edge, only one of which or none of which make physical contact with the lower member, the upper lid member also having a slit through a cross-section thereof, substantially in registry with the slit in the lower member when the upper member is operationally positioned on the lower member. - View Dependent Claims (15, 16)
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17. A combination of a coil and an electrostatic shield therefor, for use in on electric current measuring device, comprising:
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a lower electrostatic shield member, generally U-shaped in cross-section, the lower member comprising an electrically-conducting,, non-magnetic material, and configured to receive a coil therein, the lower member having a cross-sectional slit therethrough to prevent an electrical loop around a perimeter thereof; an upper, flat electrostatic shield lid member comprising an electrically-conducting, non-magnetic material, configured to fit on top of the lower member, wherein the lid member has an inner peripheral edge and an outer peripheral edge, only one of which or none of which make physical contact with the lower member, the upper lid member also having a cross-sectional slit therethrough, substantially in registry with the slit in the lower member when operatively positioned with the lower member; a coil positioned within the volume defined between the upper and lower members; and encapsulating material substantially covering the coil within the electrostatic shield. - View Dependent Claims (18, 19, 20, 21)
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Specification