Patent Publication Number: US-11651903-B1

Title: Capacitor for multiple replacement applications

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application and claims priority under 35 USC § 120 to U.S. application Ser. No. 16/678,500, filed Nov. 8, 2019, which is a continuation of U.S. application Ser. No. 16/195,077, filed Nov. 19, 2018, which is a continuation of U.S. application Ser. No. 15/585,782, filed May 3, 2017, now U.S. Patent No. 10,134,528, which is a continuation of U.S. application Ser. No. 15/097,383, filed Apr. 13, 2016, now U.S. Pat. No. 10,249,439, which is a continuation of U.S. application Ser. No. 13/601,205, filed Aug. 31, 2012, now U.S. Pat. No. 9,343,238 issued on May 17, 2016, which is a continuation of U.S. application Ser. No. 12/945,979, filed Nov. 15, 2010, now U.S. Pat. No. 8,270,143 issued on Sep. 18, 2012, which is a continuation of U.S. application Ser. No. 12/246,676, filed Oct. 7, 2008, now U.S. Pat. No. 7,835,133 issued on Nov. 16, 2010, which is a continuation application of U.S. application Ser. No. 11/733,624, filed Apr. 10, 2007, now U.S. Pat. No. 7,474,519 issued on Jan. 6, 2009, which is a continuation application of U.S. application Ser. No. 11/317,700, filed on December 23, 2005, now U.S. Pat. No. 7,203,053 issued on Apr. 10, 2007, which claims benefit to U.S. Provisional Application Serial No. 60/669,712, filed Apr. 7, 2005. 
     FIELD OF THE INVENTION 
     The invention herein relates to a capacitor with multiple capacitor sections selectively connectable to match the capacitance or capacitances of one or more capacitors being replaced. 
     BACKGROUND OF THE INVENTION 
     One common use for capacitors is in connection with the motors of air -conditioning systems. The systems often employ two capacitors, one used in association with a compressor motor and another smaller value capacitor for use in association with a fan motor. Air-conditioning systems of different BTU capacity, made by different manufacturers or being a different model all may use capacitors having different values. These capacitors have a finite life and sometimes fail, causing the system to become inoperative. 
     A serviceman making a service call usually will not know in advance whether a replacement capacitor is necessary to repair an air-conditioning system, or what value capacitor or capacitors might be needed to make the repair. One option is for the serviceman to carry a large number of capacitors of different values in the service truck, but it is difficult and expensive to maintain such an inventory, especially because there can be a random need for several capacitors of the same value on the same day. The other option is for the serviceman to return to the shop or visit a supplier to pick up a replacement capacitor of the required value. This is inefficient as the travel time to pick up parts greatly extends the overall time necessary to complete a repair. This is extremely detrimental if there is a backlog of inoperative air-conditioning systems on a hot day. This problem presents itself in connection with air-conditioning systems, but is also found in any situation where capacitors are used in association with motors and are replaced on service calls. Other typical examples are refrigeration and heating systems, pumps, and manufacturing systems utilizing compressors. 
     A desirable replacement capacitor would have the electrical and physical characteristics of the failed capacitor, i.e. it should provide the same capacitance value or values at the same or higher voltage rating, be connectable using the same leads and be mountable on the same brackets or other mounting provision. It should also have the same safety protection, as confirmed by independent tests performed by Underwriter Laboratories or others. Efforts have been made to provide such a capacitor in the past, but they have not resulted in a commercially acceptable capacitor adapted for replacing capacitors having a wide range of capacitance values. 
     My U.S. Pat. Nos. 3,921,041 and 4,028,595 disclose dual capacitor elements in the form of two concentric wound capacitor sections. My U.S. Pat. No. 4,263,638 also shows dual capacitors sections formed in a wound capacitive element, and my U.S. Pat. No. 4,352,145 shows a wound capacitor with dual elements, but suggests that multiple concentric capacitive elements may be provided, as does my U.S. Pat. Nos. 4,312,027 and 5,313,360. None of these patents show a capacitor having electrical and physical characteristics necessary to replace any one of the variety of failed capacitors that might be encountered on a service call. 
     An effort to provide a capacitor with multiple, selectable capacitance values is described in my U.S. Pat. No. 4,558,394. Three capacitance sections are provided in a wound capacitor element that is encapsulated in a plastic insulating material. An external terminal lug is connected with one of capacitor&#39;s sections and a second external terminal lug is provided with a common connection to all three capacitor sections. Pre-wired fixed jumper leads each connect the three capacitive sections in parallel, and the pre-wired fixed jumper leads have a portion exposed above the plastic encapsulation. This permits one or two jumper leads to be severed to remove one or two of the capacitor sections from the parallel configuration, and thereby to adjust the effective capacitance value across the terminal lugs. The &#39;394 patent suggests that further combinations could be made with different connections, but does not provide any suitable means for doing so. Another attempt to provide a capacitor wherein the capacitance may be selected on a service call is described in my U.S. Pat. No. 5,138,519. This capacitor has two capacitor sections connected in parallel, and has two external terminals for connecting the capacitor into a circuit. One of the terminals is rotatable, and one of the capacitor sections is connected to the rotatable terminal by a wire which may be broken by rotation of the terminal. This provides for selectively removing that capacitor section and thereby reducing the capacitance of the unit to the value of the remaining capacitor. This capacitor provides a choice of only two capacitance values in a fluid-filled case with a cover incorporating a pressure interrupter system. 
     In another effort to provide a universal adjustable capacitor for AC applications, American Radionic Co., Inc. produced a capacitor having five concentric capacitor sections in a cylindrical wound capacitor element. A common lead was provided from one end of the capacitor sections, and individual wire leads were provided from the other ends of the respective capacitor sections. The wound capacitor element was encapsulated in a plastic insulating material with the wire leads extending outwardly from the encapsulating material. Blade connectors were mounted at the ends of the wire leads, and sliding rubber boots were provided to expose the terminals for making connections and for shielding the terminals after connections were made. Various capacitance values could be selected by connecting various ones of the capacitor sections in parallel relationship, in series relationship, or in combinations of parallel and series relationships. In a later version, blade terminals were mounted on the encapsulating material. These capacitors did not meet the needs of servicemen. The connections were difficult to accomplish and the encapsulated structure did not provide pressure interrupter protection in case of capacitor failure, wherein the capacitors did not meet industry safety standards and did not achieve commercial acceptance or success. 
     Thus, although the desirability of providing a serviceman with a capacitor that is adapted to replace failed capacitors of a variety of values has been recognized for a considerable period of time, a capacitor that meets the serviceman&#39;s needs in this regard has not heretofore been achieved. This is a continuing need and a solution would be a considerable advance in the art. 
     SUMMARY OF THE INVENTION 
     It is a principal object of the invention herein to provide a capacitor that is connectable with selectable capacitance values. 
     It is another object of the invention herein to provide a capacitor incorporating multiple capacitance values that may be connected in the field to replace the capacitance value or values of a failed capacitor. 
     It is a further object of the invention herein to provide a capacitor having the objectives set forth above and which operates to disconnect itself from an electrical circuit upon a pressure-event failure. 
     It is also an object of the invention herein to incorporate multiple capacitance values in a single replacement capacitor that is adapted for connecting selected ones of the multiple capacitance values into a circuit. 
     Yet another object of the invention herein to provide a capacitor having one or more of the foregoing objectives and which provides for safely making and maintaining connections thereto. 
     It is a further object of the invention herein to increase the flexibility of replacing failed capacitors with capacitors incorporating multiple capacitance values by utilizing a range of tolerances in selecting the multiple capacitance values provided. 
     It is another principal object of the invention herein to provide a capacitor for replacing any one of a plurality of failed capacitors having different capacitance values and to meet or exceed the ratings and safety features of the failed capacitor. 
     In carrying out the invention herein, a replacement capacitor is provided having a plurality of selectable capacitance values. A capacitive element has a plurality of capacitor sections, each having a capacitance value. Each capacitor section has a section terminal and the capacitor sections have a capacitive element common terminal. The capacitive element is received in a case together with an insulating fluid at least partially and preferably substantially surrounding the capacitive element. The case is provided with a pressure interrupter cover assembly, including a cover having a common cover terminal and a plurality of section cover terminals thereon. The section terminals of the capacitive element are respectively connected to the section cover terminals and the common terminal of the capacitive element is connected to the common cover terminal, with the pressure interrupter cover assembly adapted to break one or more connections as required to disconnect the capacitive element from an electrical circuit in the event that the capacitive element has a catastrophic pressure-event failure. The replacement capacitor is connected into an electrical circuit to replace a failed capacitor by connections to selected ones of the common cover terminal and section cover terminals, the capacitor sections and connections being selected to provide one or more capacitance values corresponding to the capacitor being replaced. Such connections may include connecting capacitor sections in parallel, connecting capacitor sections in series, connecting capacitor sections in combinations of parallel and series, and connecting one or more capacitor sections separately to provide two or more independent capacitance values. 
     In one preferred aspect of the invention, the capacitive element is a wound cylindrical capacitive element having a plurality of concentric wound capacitor sections, each having a capacitance value. The number of capacitor sections is preferably six, but may be four or five, or may be greater than six. The capacitor section with the largest capacitance value is one of the outer three sections of the capacitive element. The capacitor sections are separated by insulation barriers and a metallic spray is applied to the ends of the capacitor sections. The insulation barriers withstand heat associated with connecting wire conductors to the capacitor sections. 
     The case is preferably cylindrical, having a cylindrical side wall, a bottom wall and an open top, to accommodate the wound cylindrical capacitive element. 
     Also, according to preferred aspects of the invention, the pressure interrupter cover assembly includes a deformable circular cover having a peripheral edge sealingly secured to the upper end of the case. The common cover terminal and section cover terminals are mounted to the cover at spaced apart locations thereon, and have terminal posts extending downwardly from the cover to a distal end. A rigid disconnect plate is supported under the cover and defines openings therethrough accommodating the terminal posts and exposing the distal ends thereof. Conductors connect the capacitor section terminals and the common element terminal to the distal ends of the respective terminal posts of the section cover terminals and common cover terminal. The conductor connections at the distal ends of the terminal posts are broken upon outward deformation of the cover. In more specific aspects, the conductors connecting the capacitor sections to the distal ends of the section cover terminal posts are insulated wires, with the ends soldered to foil tabs that are welded or soldered to the distal ends of the terminal posts adjacent the disconnect plate. 
     Also, according to aspects of the invention herein, the common cover terminal is positioned generally centrally on the cover, and the section cover terminals are positioned at spaced apart locations surrounding the common cover terminal. The section cover terminals include at least one blade connector, and preferably two or more blade connectors extending outwardly from the cover for receiving mating connectors for connecting selected ones of the capacitor sections into an electrical circuit. The common cover terminal preferably has four blade connectors. 
     Additional aspects of the invention include providing means insulating the section and common cover terminals, the insulating means including cylindrical cups upstanding from the cover, with the cylindrical cup of at least the common cover terminal extending to or above the blades thereof. According to a preferred aspect of the invention, the insulation means includes a cover insulation barrier having a barrier cup upstanding from the cover and substantially surrounding a central common cover terminal and further having barrier fins radially extending from the barrier cup and deployed between adjacent section cover terminals. 
     The invention herein is carried out by connecting one or more capacitor sections into an electrical circuit, by attaching leads to the cover terminals. This includes connecting capacitor sections in parallel, connecting capacitor sections in series, connecting individual capacitor sections, or connecting capacitor sections in combinations of parallel and series, as required to match the capacitance value or values of the failed capacitor being replaced. The capacitor sections can be connected to replace multiple capacitor values, as required, to substitute the capacitor for the capacitor that has failed. 
     In another aspect of the invention, the capacitance values of the capacitor sections are varied within a tolerance range from a stated value, such that one capacitor section may be utilized effectively to replace one of two values, either individually or in combinations of capacitor sections. 
     Other and more specific objects and features of the invention herein will, in part, be understood by those skilled in the art and will, in part, appear in the following description of the preferred embodiments, and claims, taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view of a capacitor according to the invention herein; 
         FIG.  2    is a top view of the capacitor of  FIG.  1   ; 
         FIG.  3    is a sectional view of the capacitor of  FIG.  1   , taken along the lines  3 - 3  of  FIG.  2   ; 
         FIG.  4    is a side elevation view of the capacitive element of the capacitor of  FIG.  1   , including wire conductors connected to the capacitor sections thereof; 
         FIG.  5    is a top view of the capacitive element of the capacitor of  FIG.  1   , including wire conductors connected to capacitor sections thereof; 
         FIG.  6    is an enlarged fragmentary plan view of a distal end of a wire conductor of  FIGS.  4  and  5   , connected to a foil tab; 
         FIG.  7    is an enlarged fragmentary side view of a distal end of a wire conductor of  FIGS.  4  and  5   , connected to a foil tab; 
         FIG.  8    is a sectional view of the capacitor of  FIG.  1    taken along the lines  8 - 8  of  FIG.  3   , and showing a pressure interrupter cover assembly of the capacitor of FIG. 1 ; 
         FIG.  9    is an exploded perspective view of the pressure interrupter cover assembly of the capacitor of  FIG.  1   ; 
         FIG.  10    is an enlarged fragmentary view of the pressure interrupter cover assembly of the capacitor of  FIG.  1   ; 
         FIG.  11    is a top view of the capacitor of  FIG.  1   , shown with selected capacitor sections connected to a fan motor and a compressor motor; 
         FIG.  12    is a schematic circuit diagram of the capacitor of  FIG.  1    connected as shown in  FIG.  11   ; 
         FIG.  13    is a top view of the capacitor of  FIG.  1    with jumper wires connecting selected capacitor sections in parallel, and also shown connected in an electrical circuit to a fan motor and a compressor motor; 
         FIG.  14    is a schematic circuit diagram of the capacitor of  FIG.  1    connected as shown in  FIG.  13   ; 
         FIG.  15    is a top view of the capacitor of  FIG.  1    connecting selected capacitor sections in series, and also shown connected in an electrical circuit to a motor; 
         FIG.  16    is a schematic circuit diagram of the capacitor of  FIG.  1    as connected shown in  FIG.  15   ; 
         FIG.  17    is a top view of the capacitor of  FIG.  1    with a jumper wire connecting selected capacitor sections in series, and also shown connected in an electrical circuit to a compressor motor; 
         FIG.  18    is a schematic circuit diagram of the capacitor of  FIG.  1    connected as shown in  FIG.  17   ; 
         FIG.  19    is a chart showing the single value capacitance values that may be provided by the capacitor of  FIG.  1   ; 
         FIG.  20    is a chart showing dual value capacitances that may be provided by the capacitor of  FIG.  1   ; 
         FIG.  21    is another chart showing dual value capacitances that may be provided by the capacitor of  FIG.  1   ; 
         FIG.  22    is another chart showing dual value capacitances that may be provided by the capacitor of  FIG.  1   ; 
         FIG.  23    is another chart showing dual value capacitances that may be provided by the capacitor of  FIG.  1   ; and 
         FIG.  24    is a sectional view of the capacitor of  FIG.  1   , taken generally along the lines  24 - 24  of  FIG.  2   , but showing the capacitor after failure of the capacitive element. 
     
    
    
     The same reference numerals refer to the same elements throughout the various Figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A capacitor  10  is shown in  FIGS.  1 - 3   , as well as in other Figures to be described below. The capacitor  10  is adapted to replace any one of a large number of capacitors. Therefore, a serviceman may carry a capacitor  10  on a service call and, upon encountering a failed capacitor, the serviceman can utilize the capacitor  10  to replace the failed capacitor with the capacitor  10  being connected to provide the same capacitance value or values of the failed capacitor. 
     The capacitor  10  has a capacitive element  12  having a plurality of capacitor sections, each having a capacitance value. The capacitive element  12  is also shown in  FIGS.  4  and  5   . In the preferred embodiment described herein, the capacitive element  12  has six capacitor sections  20 - 25 . The capacitive element  12  is a wound cylindrical element manufactured by extension of the techniques described in my prior U.S. Pat. Nos. 3,921,041, 4,028,595, 4,352,145 and 5,313,360, incorporated herein by reference. Those patents relate to capacitive elements having two capacitor sections rather than a larger plurality of capacitor sections, such as the six capacitor sections  20 - 25  of the capacitive element  12 . Accordingly, the capacitive element  12  has a central spool or mandrel  28 , which has a central opening  29 . First and second dielectric films, each having a metalized layer on one side thereof, are wound in cylindrical form on the mandrel  28  with the nonmetalized side of one film being in contact with the metalized side of the other. Selected portions of one or both of the metalized layers are removed in order to provide a multiple section capacitor. Element insulation barriers are inserted into the winding to separate the capacitor sections, the element insulation barriers also assuming a cylindrical configuration. Five element insulation barriers  30 - 34  are provided to separate the six capacitor sections  20 - 25 , with element insulation barrier  30  separating capacitor sections  20  and  21 , element insulation barrier  31  separating capacitor sections  21  and  22 , element insulation barrier  32  separating capacitor sections  22  and  23 , element insulation barrier  33  separating capacitor sections  23  and  24 , and element insulation barrier  34  separating capacitor sections  24  and  25 . The element insulation barriers are insulating polymer sheet material, which in the capacitive element  12  is polypropylene having a thickness of 0.005 inches, wound into the capacitive element  12 . Thickness of 0.0025 to 0.007 may be used. Other materials may also be used. The barriers each have about 2%-4 wraps of the polypropylene sheet material, wherein the element insulation barriers have a thickness of about 0.013 to 0.020 inches. The barriers  30 - 34  are thicker than used before in capacitors with fewer capacitor sections. The important characteristic of the barriers  30 - 34  is that they are able to withstand heat from adjacent soldering without losing integrity of electrical insulation, such that adjacent sections can become bridged. 
     As is known in the art, the metalized films each have one unmetalized marginal edge, such that the metalized marginal edge of one film is exposed at one end of the wound capacitive element  12  and the metalized marginal edge of the other film is exposed at the other end of the capacitive element  12 . With reference to  FIGS.  3  and  5   , at the lower end of the capacitance element  12 , the barriers  30 - 34  do not extend from the film, and an element common terminal  36  is established contacting the exposed metalized marginal edges of one metalized film of all the capacitor sections  20 - 25 . The element common terminal  36  is preferably a zinc spray applied onto the end of the capacitive element  12 . 
     At the top end of the capacitive element  12  as depicted in  FIGS.  3  and  5   , the element insulation barriers  30 - 34  extend above the wound metalized film. An individual capacitor element section terminal is provided for each of the capacitive sections  20 - 25 , also by applying a zinc or other metallic spray onto the end of the capacitive element  12  with the zinc being deployed on each of the capacitor sections  20 - 25  between and adjacent the element insulation barriers  30 - 34 . The element section terminals are identified by numerals  40 - 45 . Element section terminal  40  of capacitor section  20  extends from the outer-most element insulation barrier  30  to the outer surface of the capacitive element  12 , and the element section terminal  45  of capacitor section  25  extends from the inner-most element insulation barrier  34  to the central mandrel  28 . Element section terminals  41 - 44  are respectively deployed on the capacitor sections  21 - 24 . 
     Conductors preferably in the form of six insulated wires  50 - 55  each have one of their ends respectively soldered to the element section terminals  40 - 45 , as best seen in  FIG.  5   . The thickness of the polypropylene barriers  30 - 34  resists any burn-through as a result of the soldering to connect wires  50 - 55  to the terminals  40 - 45 . 
     The insulation of the wires  50 - 55  is color coded to facilitate identifying which wire is connected to which capacitor section. Wire  50  connected to element section terminal  40  of capacitor section  20  has blue insulation, wire  51  connected to element section terminal  41  of capacitor section  21  has yellow insulation, wire  52  connected to element section terminal  42  of capacitor section  22  has red insulation, wire  53  connected to element section terminal  43  of capacitor section  23  has white insulation, wire  54  connection to element section terminal  44  of capacitor section  24  has white insulation, and wire  55  connected to element section terminal  45  of capacitor section  25  has green insulation. These colors are indicated on  FIG.  4   . 
     The capacitive element  12  is further provided with foil strip conductor  38 , having one end attached to the element common terminal  36  at  37 . The foil strip conductor  38  is coated with insulation, except for the point of attachment  37  and the distal end  39  thereof. The conductor  50  connected to the outer capacitor element section  20  and its terminal  30  may also be a foil strip conductor. If desired, foil or wire conductors may be utilized for all connections. 
     In the capacitive element  12  used in the capacitor  10 , the capacitor section  20  has a value of 25.0 microfarads and the capacitor section  21  has a capacitance of 20.0 microfarads. The capacitor section  22  has a capacitance of 10.0 microfarads. The capacitor section  23  has a capacitance of 5.5 microfarads, but is identified as having a capacitance of 5.0 microfarads for purposes further discussed below. The capacitor section  24  has a capacitance of 4.5 microfarads but is labeled as having a capacitance of 5 microfarads, again for purposes described below. The capacitor section  25  has a capacitance of 2.8 microfarads. The capacitor section  20  with the largest capacitance value also has the most metallic film, and is therefore advantageously located at the outer section or at least one of the three outer sections of the capacitive element  12 . 
     The capacitor  10  also has a case  60 , best seen in  FIGS.  1 - 3   , having a cylindrical side wall  62 , a bottom wall  64 , and an open top  66  of side wall  62 . The case  60  is formed of aluminum and the cylindrical side wall  62  has an outside diameter of 2.50 inches. This is a very common diameter for capacitors of this type, wherein the capacitor  10  will be readily received in the mounting space and with the mounting hardware provided for the capacitor being replaced. Other diameters may, however, be used, and the case may also be plastic or of other suitable material. 
     The capacitive element  12  with the wires  50 - 55  and the foil strip  38  are received in the case  60  with the element common terminal  36  adjacent the bottom wall  64  of the case. An insulating bottom cup  70  is preferably provided for insulating the capacitive element from the bottom wall  64 , the bottom cup  70  having a center post  72  that is received in the center opening  29  of the mandrel  28 , and an up-turned skirt  74  that embraces the lower side wall of the cylindrical capacitive element  12  and spaces it from the side wall  62  of the case  60 . An insulating fluid  76  is provided within the case  60 , at least partly and preferably substantially surrounding the capacitive element  12 . The fluid  76  may be the fluid described in my U.S. Pat. No. 6,014,308, incorporated herein by reference, or one of the other insulating fluids used in the trade, such as polybutene. 
     The capacitor  10  also has a pressure interrupter cover assembly  80  best seen in  FIGS.  1 - 3 ,  8 - 10  and  24   . The cover assembly  80  includes a deformable circular cover  82  having an upstanding cylindrical skirt  84  and a peripheral rim  86  as best seen in  FIGS.  9  and  10   . The skirt  84  fits into the open top  66  cylindrical side wall  62  of case  60 , and the peripheral rim  86  is crimped to the open top  66  of the case  60  to seal the interior of the capacitor  10  and the fluid  76  contained therein, as shown in  FIGS.  1  and  3   . 
     The pressure interrupter cover assembly  80  includes seven cover terminals mounted on the deformable cover  82 . A common cover terminal  88  is mounted generally centrally on the cover  82 , and section cover terminals  90 - 95 , each respectively corresponding to one of the capacitor sections  20 - 25 , are mounted at spaced apart locations surrounding the common cover terminal  88 . With particular reference to  FIGS.  1 ,  2 ,  9  and  10   , the section cover terminal  91  has three upstanding blades  98 ,  100  and  102  mounted on the upper end of a terminal post  104 . Terminal post  104  has a distal end  105 , opposite the blades  98 ,  100  and  102 . The cover  82  has an opening  106  for accommodating the terminal post  104 , and has a beveled lip  107  surrounding the opening. A shaped silicone insulator  108  fits snuggly under the cover in the beveled lip  107  and the terminal post  104  passes through the insulator  108 . On the upper side of the cover, an insulator cup  110  also surrounds the post  104 , and the insulator cup  110  sits atop the silicone insulator  108 ; thus, the terminal  91  and its terminal post  104  are well insulated from the cover  82 . The other cover section terminals  92 - 95  are similarly mounted with an insulator cup and a silicone insulator. 
     The common cover terminal  88  has four blades  120 , and a terminal post  122  that passes through a silicone insulator  112 . The common cover terminal  88  mounts cover insulator barrier  114  that includes an elongated cylindrical center barrier cup  116  surrounding and extending above the blades  120  of the cover common terminal  88 , and six barrier fins  118  that extend respectively radially outwardly from the elongated center barrier cup  116  such that they are deployed between adjacent section cover terminals  90 - 95 . This provides additional protection against any arcing or bridging contact between adjacent section cover terminals or with the common cover terminal  88 . Alternatively, the common cover terminal  88  may be provided with an insulator cup  116 , preferably extending above blades  120  but with no separating barrier fins, although the barrier fins  118  are preferred. The terminal post  122  extends through an opening in the bottom of the base  117  of the insulating barrier cup  116 , and through the silicone insulator  112 , to a distal end  124 . 
     The pressure interrupter cover assembly  80  has a fiberboard disc  126  through which the terminal posts  122 , terminal post  104  and the terminal posts of the other section cover terminals extend. The disc  126  may be also fabricated of other suitable material, such as polymers. The terminal posts  104 ,  122 , etc. are configured as rivets with rivet flanges  128  for assembly purposes. The terminal posts  104 ,  122 , etc. are inserted through the disc  126 , insulators  108 ,  112 , insulator cups  110  and barrier cup  116 , and the cover terminals  88 ,  90 - 95  are spot welded to the ends of the rivets opposite the rivet flanges  128 . Thus, the rivet flanges  128  secure the cover terminals  88 ,  90 - 95  in the cover  82 , together with the insulator barrier  114 , insulator cups  110  and silicone insulators  108 ,  112 . The fiberboard disc  126  facilitates this assembly, but may be omitted, if desired. The distal ends of the terminal posts are preferably exposed below the rivet flanges  128 . 
     The cover assembly  80  has a disconnect plate  130 , perhaps best seen in  FIGS.  3 ,  9  and  10   . The disconnect plate  130  is made of a rigid insulating material, such as a phenolic, is spaced below the cover  82  by a spacer  134  in the form of a skirt. The disconnect plate  130  is provided with openings accommodating the distal ends of the terminal posts, such as opening  136  accommodating the distal end  105  of terminal post  104  and opening  138  accommodating the distal end  124  of the terminal post  122 . With particular reference to  FIG.  9   , the disconnect plate  130  may be provided with raised guides, such as linear guides  140  and dimple guides  142 , generally adjacent the openings accommodating the distal ends of terminal posts. These guides are for positioning purposes as discussed below. 
     In prior capacitors having three or fewer capacitor sections, the conductors between the capacitor sections and the terminal posts were generally foil strips, such as the one used for the common terminal  36  of the capacitive element  12  herein. The foil strips were positioned on a breaker plate over the distal ends of terminal posts, and were welded to the distal ends of the terminal posts. In capacitor  10 , the distal end  39  of the foil strip  38  is connected to the distal end  124  of terminal post  122  by welding, as in prior capacitors. 
     The wires  50 - 55  are not well-configured for welding to the distal ends of the terminal posts of the cover section terminals. However, the wires  50 - 55  are desirable in place of foil strips because they are better accommodated in the case  60  and have good insulating properties, resist nicking and are readily available with colored insulations. In order to make the necessary connection of the wires  50 - 55  to their respective terminal posts, foil tabs  56  are welded to each of the distal ends of the terminal posts of the section cover terminals  90 - 95 , and the guides  140 ,  142  are helpful in positioning the foil tabs  56  for the welding procedure. The attachment may be accomplished by welding the distal end of a foil strip to the terminal post, and then cutting the foil strip to leave the foil tab  56 . Thereafter, and as best seen in  FIGS.  6 ,  7  and  10   , the conductor  58  of wire  50  is soldered to the tab  56 , by solder  57 . The insulation  59  of wire  50  has been stripped to expose the conductor  58 . The other wires  51 - 55  are similarly connected to their respective cover section terminals. Alternatively, the foil tabs may be soldered to the wires and the tabs may then be welded to the terminal posts, if desired, or other conductive attachment may be employed. 
     Accordingly, each of the capacitor sections  20 - 25  is connected to a corresponding section cover terminal  90 - 95  by a respective one of color coded wires  50 - 55 . The insulator cups  110  associated with each of the section cover terminals  90 - 95  are also color coded, using the same color scheme as used in the wires  50 - 55 . This facilitates assembly, in that each capacitor section and its wire conductor are readily associated with the correct corresponding section cover terminal, so that the correct capacitor sections can be identified on the cover to make the desired connections for establishing a selected capacitance value. 
     The connections of the wires  50 - 55  and the foil  38  to the terminal posts is made prior to placing the capacitive element  12  in the case  60 , adding the insulating fluid  76 , and sealing the cover  82  of cover assembly  80  to the case  60 . The case  60  may be labeled with the capacitance values of the capacitance sections  20 - 25  adjacent the cover terminals, such as on the side of case  60  near the cover  82  or on the cover  82 . 
     The capacitor  10  may be used to replace a failed capacitor of any one of over two hundred different capacitance values, including both single and dual applications. Therefore, a serviceman is able to replace virtually any failed capacitor he may encounter as he makes service calls on equipment of various manufacturers, models, ages and the like. 
     As noted above, the capacitor  10  is expected to be used most widely in servicing air conditioning units. Air conditioning units typically have two capacitors; a capacitor for the compressor motor which may or may not be of relatively high capacitance value and a capacitor of relatively low capacitance value for a fan motor. The compressor motor capacitors typically have capacitances of from 20 to about 60 microfarads. The fan motor capacitors typically have capacitance values from about 2.5 to 12.5 microfarads, and sometimes as high as 15 microfarads, although values at the lower end of the range are most common. 
     With reference to  FIG.  11   , capacitor  10  is connected to replace a compressor motor capacitor and a fan motor capacitor, where the compressor motor capacitor has a value of 25.0 microfarads and the fan motor capacitor has a value of 4.0 microfarads. The 25.0 microfarad replacement capacitance for the compressor motor is made by one of the compressor motor leads  160  being connected to one of the blades of the blue section cover terminal  90  of capacitance section  20 , which has a capacitance value of 25.0 microfarads, and the other compressor motor lead  161  being connected to one of the blades  120  of common cover terminal  88 . The lead  162  from the fan motor is connected to the white section cover terminal  94  of capacitor section  24 , and the second lead  163  from the fan motor is also connected to the common cover terminal  88 . As set forth above, the actual capacitance value of the capacitor section  24  that is connected to the section cover terminal  94  is 4.5 microfarads, and the instructions andlor labeling for the capacitor  10  indicate that the capacitor section  24  as represented at terminal  94  should be used for a 4.0 microfarad replacement. Preferred labeling for this purpose can be “5.0 (4.0) microfarads” or similar. The 4.5 microfarad capacitance value is within approximately 10% of the specified 4.0 microfarad value, and that is within acceptable tolerances for proper operation of the fan motor. Of course, the capacitor section  24  and terminal  94  may be connected to replace a 5.0 microfarad capacitance value as well, whereby the 4.5 microfarad actual capacitance value of capacitor section  24  gives added flexibility in replacing failed capacitors. Similarly, the 5.5 microfarad capacitor section  23  can be used for either 5.0 microfarad or 6.0 microfarad replacement, and the 2.8 microfarad section  25  can be used for a 3.0 microfarad replacement or for a 2.5 microfarad additive value.  FIG.  12    schematically illustrates the connection of capacitor sections  20  and  24  to the compressor motor and fan motor shown in  FIG.  11   . 
       FIG.  13    illustrates another connection of the capacitor  10  for replacing a 60.0 microfarad compressor motor capacitor and a 7.5 microfarad fan motor capacitor. The formula for the total capacitance value for capacitors connected in parallel is additive namely: C t =C 1 +C 2 +C 3  . . . Therefore, with reference to  FIG.  13   , a 60.0 microfarad capacitance value for the compressor motor is achieved by connecting in parallel the section cover terminal  90  (capacitor section  20  at a value of 25.0 microfarads), section cover terminal  91  (capacitor section  21  at a value of 20.0 microfarads), section cover terminal  92  (capacitor section  22  at a value of 10.0 microfarads) and section cover terminal  93  (capacitor section  23  at a nominal value of 5.0 microfarads). The foregoing connections are made by means of jumpers  164 ,  165  and  166 , which may be supplied with the capacitor  10 . Lead  167  is connected from the section cover terminal  90  of the capacitor section  20  to the compressor motor, and lead  168  is connected from the common cover terminal  88  to the compressor motor. This has the effect of connecting the specified capacitor sections  20 ,  21 ,  22  and  23  in parallel, giving a total of 60.0 microfarad capacitance; to wit: 25+20+10+5=60. It is preferred but not required to connect the lead from the compressor motor or the fan motor to the highest value capacitor section used in providing the total capacitance. 
     Similarly, a 7.5 microfarad capacitance is provided to the fan motor by connecting section cover terminal  94  of the 5.0 microfarad capacitor section  24  and the section cover terminal  95  of the nominal 2.5 microfarad capacitor section  25  in parallel via jumper  169 . Leads  170  and  171  connect the fan motor to the common cover terminal  88  and the section cover terminal  95  of the capacitor section  25 .  FIG.  14    diagrammatically illustrates the connection of the capacitor  10  shown in  FIG.  13   . 
     It will be appreciated that various other jumper connections between section cover terminals can be utilized to connect selected capacitor sections in parallel, in order to provide a wide variety of capacitance replacement values. 
     The capacitor sections can also be connected in series to utilize capacitor  10  as a single value replacement capacitor. This has the added advantage of increasing the voltage rating of the capacitor  10  in a series application, i.e. the capacitor  10  can safely operate at higher voltages when its sections are connected in series. As a practical matter, the operating voltage will not be increased as it is established by the existing equipment and circuit, and the increased voltage rating derived from a series connection will increase the life of the capacitor  10  because it will be operating well below its maximum rating. 
     With reference to  FIG.  15   , the capacitor  10  is shown with capacitor section  22  (terminal  92 ) having a value of 10.0 microfarads connected in series with capacitor section  25  (terminal  95 ) having a nominal value of 2.5 microfarads to provide a replacement capacitance value of 2.0 microfarads. Leads  175  and  176  make the connections from the respective section cover terminals  92  and  95  to the motor, and the element common terminal  36  connects the capacitor sections  22  and  25  of capacitive element  12 . With reference to  FIG.  16   , the connection of capacitor  10  shown in  FIG.  15    is illustrated diagrammatically. In both  FIGS.  15  and  16   , it will be seen that the cover common terminal  88  is not used in making series connections. 
     The formula for capacitance of capacitors connected in series is: 
     
       
         
           
             
               
                 1 
                 
                   C 
                   T 
                 
               
               = 
               
                 
                   1 
                   
                     C 
                     1 
                   
                 
                 + 
                 
                   1 
                   
                     C 
                     2 
                   
                 
                 + 
                 
                   1 
                   
                     C 
                     3 
                   
                 
               
             
             ⁢ 
             … 
           
         
       
     
     Therefore, 
     
       
         
           
             
               
                 C 
                 T 
               
               = 
               
                 
                   
                     C 
                     1 
                   
                   × 
                   
                     C 
                     2 
                   
                 
                 
                   
                     C 
                     1 
                   
                   + 
                   
                     C 
                     2 
                   
                 
               
             
             , 
           
         
       
     
     and the total capacitance of the capacitor sections  22  and  25  connected as shown in  FIGS.  15  and  16    is 
     
       
         
           
             
               
                 C 
                 T 
               
               = 
               
                 
                   
                     10.0 
                     × 
                     2.5 
                   
                   
                     
                       1 
                       ⁢ 
                       
                         0 
                         . 
                         0 
                       
                     
                     + 
                     2.5 
                   
                 
                 = 
                 
                   
                     
                       2 
                       ⁢ 
                       5 
                     
                     
                       1 
                       ⁢ 
                       
                         2 
                         . 
                         5 
                       
                     
                   
                   = 
                   
                     2 
                     . 
                     0 
                   
                 
               
             
             ⁢ 
             
                 
             
             ⁢ 
             
               microfarads 
               . 
             
           
         
       
     
     The capacitance of each of the capacitor sections  20 - 25  is rated at 440 volts. However, when two or more capacitor sections  20 - 25  are connected in series, the applied voltage section is divided between the capacitor sections in inverse proportion to their value. Thus, in the series connection of  FIGS.  15  and  16   , the nominal 2.5 microfarad section sees about 80% of the applied voltage and the 10.0 microfarad section sees about 20% of the applied voltage. The net effect is that the capacitor  10  provides the 2.0 microfarad replacement value at a higher rating, due to the series connection. In this configuration, the capacitor  10  is lightly stressed and is apt to have an extremely long life. 
     With reference to  FIG.  17   , the capacitor sections of the capacitor  10  are shown connected in a combination of parallel and series connections to provide additional capacitive values at high voltage ratings, in this case 5.0 microfarads. The two capacitor sections  23  and  24  each having a nominal value of 5.0 microfarads are connected in parallel by jumper  177  between their respective cover section terminals  93  and  94 . The leads  178  and  179  from a compressor motor are connected to the section cover terminal  92  of capacitor section  22  having a value of 10.0 microfarads, and the other lead is connected to cover section terminal  94  of capacitor section  24 . Thus, a capacitance value of 5.0 microfarads is provided according to the following 
     
       
         
           
             
               1 
               
                 C 
                 T 
               
             
             = 
             
               
                 1 
                 
                   C 
                   1 
                 
               
               + 
               
                 1 
                 
                   C 
                   2 
                 
               
             
           
         
       
     
     where C 1  is a parallel connection having the value C+C, in this case 5.0+5.0 for a C 1  of 10.0 microfarads. With that substitution, the total value is 
     
       
         
           
             
               C 
               T 
             
             = 
             
               
                 
                   10.0 
                   × 
                   10. 
                   ⁢ 
                   0 
                 
                 
                   
                     1 
                     ⁢ 
                     0 
                   
                   + 
                   
                     1 
                     ⁢ 
                     0 
                   
                 
               
               = 
               
                 
                   
                     1 
                     ⁢ 
                     0 
                     ⁢ 
                     0 
                   
                   
                     2 
                     ⁢ 
                     0 
                   
                 
                 = 
                 
                   5.0 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     microfarads 
                     . 
                   
                 
               
             
           
         
       
     
     The connection of capacitor  10  illustrated in  FIG.  17    is shown diagrammatically in  FIG.  18   . 
       FIG.  19    is a chart showing single capacitance values that can be provided by the capacitor  10  connected in parallel. The values are derived by connecting individual capacitor sections into a circuit, or by parallel connections of capacitor sections. The chart should be interpreted remembering that the 2.8 microfarad capacitor section can be used as a 2.5 or 3.0 microfarad replacement, and that the two 5.0 microfarad values are actually 4.5 and 5.5 microfarad capacitor sections, also with possibilities for more replacements. 
       FIGS.  20 - 23    are charts showing applications of capacitor  10  in replacing both a fan motor capacitor and a compressor motor capacitor. This is an important capability, because many air conditioning systems are equipped with dual value capacitors and when one of the values fails, another dual value capacitor must be substituted into the mounting space bracket. 
     The chart of  FIG.  20    shows dual value capacitances that can be provided by capacitor  10  wherein the nominal 2.5 microfarad capacitor section  25  is used for one of the dual values, usually the fan motor. Fan motors are generally not rigid in their requirements for an exact capacitance value, wherein the capacitor section  25  may also be used for fan motors specifying a 3.0 microfarad capacitor. The remaining capacitor sections  20 - 24  are available for connection individually or in parallel to the compressor motor, providing capacitance values from 5.0 to 65.0 microfarads in 5.0 microfarad increments. 
     The chart of  FIG.  21    also shows dual value capacitances that can be provided by capacitor  10 . In the chart of  FIG.  21   , one of the dual values is 5.0 microfarads that can be provided by either capacitor section  23  having an actual capacitance value of 5.5 microfarads or by capacitor section  24  having an actual capacitance of 4.5 microfarads. As discussed above, the capacitor section  24  can also be used for a 4.0 microfarad replacement value, and capacitor section  23  could be used for a 6.0 microfarad replacement value. Thus, chart  21  represents more dual replacement values than are specifically listed. The other capacitor section may be used in various parallel connections to achieve the second of the dual capacitance values. 
     Chart  22  illustrates yet additional dual value capacitances that can be provided by capacitor  10 . Capacitor section  25  (nominal 2.5 microfarads) is connected in parallel with one of capacitor section  23  (5.5 microfarads) or capacitor section  24  (4.5 microfarads) to provide a 7.5 microfarad capacitance value as one of the dual value capacitances. The remaining capacitor sections are used individually or in parallel to provide the second of the dual value capacitances. 
     Chart  23  illustrates yet additional dual value capacitances that can be provided by capacitor  10 , where capacitor section  22  (10 microfarads) is dedicated to provide one of the dual values. The remaining capacitor sections are used individually or in parallel for the other of the dual values. 
     It will be appreciated that any one or group of capacitor sections may be used for one of a dual value, with a selected one or group of the remaining capacitor sections connected to provide another capacitance value. Although there are no known applications, it will also be appreciated that the capacitor  10  could provide six individual capacitance values corresponding to the capacitor sections, or three, four or five capacitance values in selected individual and parallel connections. Additional single values can be derived from series connections. 
     The six capacitor sections  20 - 25  can provide hundreds of replacement values, including single and dual values. It will further be appreciated that if fewer replacement values are required, the capacitor  10  can be made with five or even four capacitor sections, and that if more replacement values were desired, the capacitor  10  could be made with more than six capacitor sections. It is believed that, at least in the intended field of use for replacement of air conditioner capacitors, there should be a minimum of five capacitor sections and preferably six capacitor sections to provide an adequate number of replacement values. 
     As is known in the art, there are occasional failures of capacitive elements made of wound metalized polymer film. If the capacitive element fails, it may do so in a sudden and violent manner, producing heat and outgassing such that high internal pressures are developed within the housing. Pressure responsive interrupter systems have been designed to break the connection between the capacitive element and the cover terminals in response to the high internal pressure, thereby removing the capacitive element from a circuit and stopping the high heat and overpressure condition within the housing before the housing ruptures. Such pressure interrupter systems have been provided for capacitors having two and three cover terminals, including the common terminal, but it has not been known to provide a capacitor with five or more capacitor sections and a pressure interrupter cover assembly. 
     The pressure interrupter cover assembly  80  provides such protection for the capacitor  10  and its capacitive element  12 . With reference to  FIG.  24   , the capacitor  10  is shown after failure. Outgassing has caused the circular cover  82  to deform upwardly into a generally domed shape. When the cover  82  deforms in the manner shown, the terminal posts are also displaced upwardly from the disconnect plate  130 , and the weld connection of the distal end  124  of common cover terminal post  122  to the distal end  39  foil lead  38  from the common element  36  of the capacitive element  12  is broken, and the welds between the foil tabs  56  and the terminal posts  104  of the section cover terminals  90 - 95  are also broken, the separation at section cover terminals  91  and  94  being shown. 
     Although the preferred pressure interrupter cover assembly includes the foil lead  38  and foil tabs  56 , frangibly connected to the distal ends of the terminal posts, the frangible connections both known in the art and to be developed may be used. As an example, the terminal posts themselves may be frangible. 
     It should be noted that although it is desirable that the connections of the capacitive element and all cover terminals break, it is not necessary that they all do so in order to disconnect the capacitive element  12  from a circuit. For all instances in which the capacitor  10  is used with its capacitor sections connected individually or in parallel, only the terminal post  122  of common cover terminal  88  must be disconnected in order to remove the capacitive element  12  from the circuit. Locating the cover common terminal  88  in the center of the cover  82 , where the deformation of the cover  82  is the greatest, ensures that the common cover terminal connection is broken both first and with certainty in the event of a failure of the capacitive element  12 . 
     If the capacitor sections of the capacitor  10  are utilized in a series connection, it is necessary that only one of the terminal posts used in the series connection be disconnected from its foil tab at the disconnect plate  130  to remove the capacitive element from an electrical circuit. In this regard, it should be noted that the outgassing condition will persist until the pressure interrupter cover assembly  80  deforms sufficiently to cause disconnection from the circuit, and it is believed that an incremental amount of outgassing may occur as required to cause sufficient deformation and breakage of the circuit connection at the terminal post of one of the section cover terminal. However, in the most common applications of the capacitor  10 , the common cover terminal  88  will be used and the central location of the common cover terminal  88  will cause fast and certain disconnect upon any failure of the capacitive element. 
     Two other aspects of the design are pertinent to the performance of the pressure interrupter system. First, with respect to series connections only, the common cover terminal  88  may be twisted to pre-break the connection of the terminal post  122  with the foil strip  38 , thus eliminating the requirement of any force to break that connection in the event of a failure of the capacitive element  12 . The force that would otherwise be required to break the connection of common terminal post  122  is then applied to the terminal posts of the section cover terminals, whereby the section cover terminals are more readily disconnected. This makes the pressure interrupter cover assembly  80  highly responsive in a series connection configuration. 
     Second, the structural aspects of welding foil tabs to the distal ends of the terminal posts corresponding to the various capacitor sections and thereafter soldering the connecting wires onto the foil tabs  56  is also believed to make the pressure interrupter cover assembly  80  more responsive to failure of the capacitive element  12 . In particular, the solder and wire greatly enhance the rigidity of the foil tabs  56  wherein upon deformation of the cover  82 , the terminal posts break cleanly from the foil tabs  56  instead of pulling the foil tabs partially through the disconnect plate before separating. Thus, the capacitor  10 , despite having a common cover terminal and section cover terminals for six capacitor sections, is able to satisfy safety requirements for fluid-filled metalized film capacitors, which is considered a substantial advance in the art. 
     The capacitor  10  and the features thereof described above are believed to admirably achieve the objects of the invention and to provide a practical and valuable advance in the art by facilitating efficient replacement of failed capacitors. Those skilled in the art will appreciate that the foregoing description is illustrative and that various modifications may be made without departing from the spirit and scope of the invention, which is defined in the following claims.