High Voltage Sensing Capacitor and Indicator Device

Abstract

A high-voltage sensing capacitor as an interface apparatus that may be used to attach an indicator unit to a high-voltage AC electrical bus and to provide safety to maintenance personnel. The high-impedance nature of the sensing capacitor effectively isolates the indicator unit from the high-voltage source to which it is connected. The sensing capacitor can be directly mounted between a high-voltage busbar and an indicator unit to provide visual and/or audible alerts to maintenance personnel when high voltage conditions are detected on the busbar. The sensing capacitor is comprised of a portable, unitary capacitive structure that includes a molded insulator body encapsulating two electrodes. The electrodes only partially or incompletely overlap within the insulator body. The electrode spacing and configuration is structured to provide a deliberate amount of coupling between the two electrodes in the presence of an AC electric field.

I claim: 
     
         1 . A sensing apparatus comprising:
 an insulator body of a dielectric material configured to allow external electrical connections;   an elongated electrode extending a distance into the insulator body; and   a hollow electrode extending a distance into an opposite end of the insulator body, the hollow electrode partially surrounding a section of the elongated electrode for an incomplete overlap and a physical separation between the elongated electrode and the hollow electrode, with the dielectric material substantially completely encapsulating the elongated and the hollow electrode and the physical separation therebetween.   
     
     
         2 . The sensing apparatus of  claim 1 , wherein the dielectric material is cycloaliphatic epoxy resin. 
     
     
         3 . The sensing apparatus of  claim 1 , wherein the elongated electrode is configured to be attached to a high voltage busbar of an AC power source. 
     
     
         4 . The sensing device of  claim 3 , wherein the hollow electrode is configured to be attached to an indicator device. 
     
     
         5 . The high voltage sensing capacitor of  claim 3 , further comprising:
 a first terminal extending a distance into the insulator body connected with the elongated electrode to allow mounting of the sensing apparatus to the AC power source.   
     
     
         6 . The sensing apparatus of  claim 1 , wherein the hollow electrode is configured to be attached to a high voltage busbar of an AC power source. 
     
     
         7 . The sensing apparatus of  claim 6 , wherein the elongated electrode is configured to be attached to an indicator device. 
     
     
         8 . The sensing apparatus of  claim 6 , further comprising:
 a second terminal extending a distance into the insulator body connected with the hollow electrode to allow mounting of the sensing apparatus to the AC power source.   
     
     
         9 . The sensing apparatus of  claim 1 , wherein said insulator body is substantially cylindrical. 
     
     
         10 . The sensing apparatus of  claim 1 , wherein said insulator body comprises a plurality of surface undulations on an outermost surface thereof. 
     
     
         11 . The sensing apparatus of  claim 1 , wherein at least one of the following is dependent on a range of operating voltages for said sensing capacitor;
 a length of said substantially cylindrical insulator body; and   a diameter of said substantially cylindrical insulator body; and   number and shape of said surface undulations.   
     
     
         12 . The sensing apparatus of  claim 1 , wherein a length and a diameter of the hollow electrode is dependent on at least one of the following:
 a length and a diameter of the insulator body; and   a degree of electrical coupling desired between the elongated and the hollow electrodes.   
     
     
         13 . An interface apparatus comprising:
 an insulator body of a dielectric material;   a hollow shaped electrode extending a distance into one end of an insulator body;   a elongated electrode extending into an opposite end of the insulator body extending a second distance into the hollow shaped electrode so the hollow shaped electrode incompletely overlaps the elongated electrode with a physical separation between the elongated electrode and the hollow shaped electrode throughout a region of the overlap to provide voltage isolation between the elongated electrode and the hollow shaped electrode, the insulator body substantially completely encapsulating the elongated electrode and the hollow shaped electrode as an interface between a high voltage busbar of an AC (alternating current) power source and an indicator unit to provide visual or audible alerts of high voltage condition.   
     
     
         14 . The interface apparatus of  claim 13 , further comprising:
 an input terminal connected to the hollow shaped electrode.   
     
     
         15 . The interface apparatus of  claim 14 , wherein the input terminal is configured to be electrically connected to the high voltage busbar when a voltage on the high voltage busbar is in the range of one of the following:
 approximately 2.3 KVAC to approximately 27 KVAC three phase; and   approximately 2.3 KVAC to approximately 18 KVAC single phase.   
     
     
         16 . The interface apparatus of  claim 15 , wherein the input terminal comprises:
 an inner portion extending a distance into the insulator body connected with the hollow shaped electrode; and   an outer portion threaded to allow mounting of the high voltage sensing capacitor onto the busbar.   
     
     
         17 . The high voltage sensing capacitor of  claim 16 , wherein the input terminal comprises:
 a threaded inner portion extending a distance into the insulator body connected with the hollow shaped electrode to allow mounting of the sensing capacitor onto the high voltage busbar.   
     
     
         18 . The interface apparatus of  claim 13 , wherein the elongated electrode is a metallic cylindrical rod that includes an output terminal to electrically connect the high voltage sensing capacitor to an indicator device. 
     
     
         19 . The interface apparatus of  claim 18 , wherein the output terminal comprises:
 an inner portion extending a distance into the insulator body connected with the elongated electrode; and   an outer threaded portion to allow connecting of the sensing capacitor onto the indicator device.   
     
     
         20 . The interface apparatus of  claim 18 , wherein the output terminal comprises:
 a threaded inner portion extending into the insulator body connected with the elongated electrode to allow connecting of the sensing capacitor onto the indicator device.   
     
     
         21 . The high voltage sensing capacitor of  claim 13 , wherein the elongated electrode, hollow shaped electrode, and the insulator body are molded together, thereby creating a unitary capacitive structure. 
     
     
         22 . The sensing capacitor of  claim 13 , wherein a capacitive coupling between said elongated electrode and hollow shaped electrodes is dependent on an extent of said overlap between said elongated and hollow cylindrical shaped electrodes.