Apparatus and process for the control of electromagnetic fields on the surface of EMI filter capacitors
First Claim
1. A capacitor assembly, comprising:
- a casing of dielectric material;
active and ground sets of electrode plates disposed within the casing to form an electromagnetic interference (EMI) filter capacitor; and
a guard electrode plate disposed within the casing adjacent to a first surface thereof, for reducing electromagnetic field stress on the first surface of the casing.
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Accused Products
Abstract
In a feedthrough terminal assembly, a guard electrode plate is disposed within the ceramic casing and adjacent to a surface of an electromagnetic interference (EMI) filter capacitor for reducing electromagnetic field stress on that surface. In a related process, the ground electrode plate is optimized utilizing computer generated electrostatic field modeling. The guard electrode plate may be grounded, either to external capacitor surface metallization or internal capacitor surface metallization. Alternatively, the guard electrode plate may float within the casing in a manner where it is electrically isolated from both the active and ground sets of electrode plates of the EMI filter capacitor. A second guard electrode plate may also be disposed within the casing adjacent to an opposite axial surface of the capacitor casing for reducing electromagnetic field stress on that adjacent surface of the casing.
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Citations
44 Claims
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1. A capacitor assembly, comprising:
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a casing of dielectric material;
active and ground sets of electrode plates disposed within the casing to form an electromagnetic interference (EMI) filter capacitor; and
a guard electrode plate disposed within the casing adjacent to a first surface thereof, for reducing electromagnetic field stress on the first surface of the casing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A capacitor assembly, comprising:
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a casing having first and second electrode plates incased therein in spaced relation to form an electromagnetic interference (EMI) filter capacitor, and at least one terminal pin bore formed axially therethrough;
at least one conductive terminal pin extending through said at least one terminal pin bore in conductive relation with said first electrode plate;
a conductive ferrule having at least one aperture formed axially therethrough, said casing being mounted to said ferrule to extend across and close said at least one ferrule aperture with said second electrode plate in conductive relation with said ferrule;
at least one hermetic seal formed from a dielectric material and extending across and sealing said at least one ferrule aperture at one axial side of said capacitor body, said at least one hermetic seal defining an inboard face presented toward said capacitor body and an outboard face presented away from said capacitor body, said at least one terminal pin extending through said at least one hermetic seal; and
a guard electrode plate disposed within said casing adjacent to a first surface thereof facing the conductive ferrule, for reducing electromagnetic field stress on the first surface of said casing. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A process for reducing electromagnetic field stress on the surface of a capacitor in a feedthrough terminal assembly, comprising the steps of:
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forming an electromagnetic interference (EMI) filter capacitor of an active electrode plate and a ground electrode plate disposed within a casing of dielectric material having at least one terminal pin bore formed axially therethrough;
including a guard electrode plate within the casing adjacent to a first surface thereof;
placing a terminal assembly comprising at least one conductive terminal pin and a conductive ferrule adjacent to the first surface of the casing such that the terminal pin extend through the terminal pin bore and is conductively coupled to the active electrode plate, and the ground electrode plate is conductively coupled to the ferrule; and
optimizing the guard electrode plate utilizing electrostatic field modeling of the feedthrough terminal assembly. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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34. A capacitor assembly, comprising:
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a casing of dielectric material;
active and ground sets of electrode plates disposed within the casing to form an electromagnetic interference (EMI) filter capacitor; and
means for marking the casing to indicate a side thereof adjacent to an active electrode plate. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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Specification