Abstract:
A pad-mounted transformer enclosure may have a wiring compartment utilizing multiple hinge points on each side panel with an additional set of hinges located at the back of the compartment area to allow the doors to be opened as normal or to allow the sides to be also opened, allowing the wiring compartment to be totally exposed on all three sides. The tank of the transformer enclosure may have a cover secured in a manner that allows the cover to be removed with simple hand tools while preventing unauthorized removal thereof, that increases tank top structural rigidity, and that does not trap water on the tank cover.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates, in general, to transformers, and in particular, to an improved padmount transformer enclosure.  
           [0003]    2. Information Disclosure Statement  
           [0004]    A preliminary patentability search in Class 174, subclass 50, and Class 312, subclasses 223.1 and 100, produced the following patents, which appear to be relevant to the present invention: Nelson et al., U.S. Pat. No. 3,014,158, issued Dec. 19, 1961; Fisher, U.S. Pat. No. 3,376,086, issued Apr. 2, 1968; Main, U.S. Pat. No. 4,003,610, issued Jan. 18, 1977; Nilsson, U.S. Pat. No. 4,466,676, issued Aug. 21, 1984; Borgmeyer et al., U.S. Pat. No. 5,189,257, issued Feb. 23, 1993; Dirk, U.S. Pat. No. 5,573,319, issued Nov. 12, 1996; Marusinec, U.S. Pat. No. 5,783,775; Arizpe et al., U.S. Pat. No. 5,823,646; Marusinec et al., U.S. Pat. No. 5,889,231, issued Mar. 30, 1999; and Reinke et al., U.S. Pat. No. 6,066,802, issued May 23, 2000.  
           [0005]    Padmount transformer enclosures are used in electrical power distribution systems to contain distribution transformers used to step down voltage from the high voltage terminal of an underground electrical distribution systems to the low voltage terminal thereof going to the end user&#39;s electrical system, etc. A typical prior art padmount transformer enclosure includes a tank for holding the core/coil assembly of the transformer immersed in oil or the like, and a wiring cabinet having high and low voltage wiring compartments for enclosing the high and low voltage bushings, respectively, of the transformer, etc. In order to prevent unauthorized access to the core/coil assembly of the transformer held within the tank of the padmount transformer enclosure, the most common prior art practice is to weld a cover over the top of the tank. Other prior art tank covers are secured with carriage bolt-nut assemblies, and include some means for shield the nuts, etc. Such shielding means result in a cover that protrudes past the top of the tank cover by several inches and causes water, etc., to be trapped along the edge of the cover. The wiring cabinet of a typical prior art padmount transformer enclosure includes left and right sidewalls, and left and right lockable doors that swing open, exposing the high and low voltage wiring compartment. One of the doors swings out to the right and the other door swings out to the left, leaving the front completely open, but the right and left sidewalls remain fixed in place.  
           [0006]    Nothing in the known prior art discloses or suggests the present invention. More specifically, nothing in the known prior art discloses or suggests a padmount transformer enclosure that allows the doors and the side walls of the wiring compartment to be opened so that the wiring compartment is totally exposed on all three sides; or a padmount transformer enclosure including a liquid tight tank having a cover that can be removed with simple hand tools without requiring removal or disassembly of the wiring compartment, and having a tamperguard which prevents removal of the cover except by authorized personnel.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    The present invention provides an improved padmount transformer enclosure for a 3-phase padmount distribution transformer or the like. One basic concept of the present invention is to provide the terminal or wiring compartment of a padmount transformer enclosure with left and right side panels that are hinged to the transformer tank front panel so that the side panels of the wiring compartment can swing open to allow the wiring compartment to be totally exposed or open on all three sides. Another basic concept of the present invention is to provide the transformer tank of a padmount transformer enclosure with a tamper proof cover that can be removed with simple hand tools by authorized personnel.  
           [0008]    One object of the present invention to provide a padmounted, distribution transformer enclosure with a tank cover that can be removed by the manufacturer or end user with simple hand tools, more easily than prior art tank covers.  
           [0009]    Another object of the present invention is to provide such a transformer enclosure with a tamperguard which requires access to the interior of a lockable wiring compartment for removal of the tank cover, with the tamperguard positioned in a box section or channel in the tank beneath the cover which strengthens the tank and allows for a unique, recessed tamperguard located under the cover rather than covering the top edge of the cover, so that there is no tendency to trap water along the edge of the cover.  
           [0010]    Another object of the present invention is to provide a padmounted, distribution transformer enclosure with a wiring compartment that can be swung open to be totally exposed on all three sides, allowing work to be done within the wiring compartment without any obstructions caused by the cabinet. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a somewhat diagrammatic front elevational view of the padmount transformer enclosure of the present invention.  
         [0012]    [0012]FIG. 2 is a somewhat diagrammatic left side elevational view of the padmount transformer enclosure of the present invention.  
         [0013]    [0013]FIG. 3 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, as taken on line  3 - 3  of FIG. 1, showing the first door panel of the wiring compartment thereof in an opened position.  
         [0014]    [0014]FIG. 4 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, similar to FIG. 3 but showing the first and second door panels of the wiring compartment thereof in opened positions.  
         [0015]    [0015]FIG. 5 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, similar to FIG. 3 but showing the first and second door panels, and the first side panel of the wiring compartment thereof in opened positions.  
         [0016]    [0016]FIG. 6 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, similar to FIG. 3 but showing the first and second door panels and the first and second side panels of the wiring compartment thereof in opened positions.  
         [0017]    [0017]FIG. 7 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, as taken on line  7 - 7  of FIG. 1, with portions thereof omitted or broken away for clarity.  
         [0018]    [0018]FIG. 8 is a somewhat diagrammatic sectional view of a portion of the padmount transformer enclosure of the present invention, as taken on line  8 - 8  of FIG. 2, with portions thereof omitted or broken away for clarity. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    A preferred embodiment of the padmount transformer enclosure of the present invention is shown in FIGS.  1 - 8 , and identified by the numeral  11 . The cabinet  11  is designed to safely house a standard three-phase electrical distribution transformer or the like mounted on a ground level platform or pad  15 , etc. Such a transformer is commonly used to step down voltage from the high voltage terminal of an underground electrical distribution systems to the low voltage terminal thereof, and includes a core/coil assembly, and electrical connectors  19  such as high voltage bushings and low voltage bushings, or other conventional couplings, to allow electrical connection between the core/coil assembly, and the high and low voltage terminals, etc.  
         [0020]    The cabinet  11  includes a transformer tank  21  having an opened top, liquid tight enclosure or vessel  23  (often referred to simply as the “tank”) for holding a quantity of oil or the like and for holding the core/coil assembly of the transformer immersed in the oil or the like as will now be apparent to those skilled in the art, and a cover or lid  25  for closing the opened top of the vessel  23 .  
         [0021]    The vessel  23  may be somewhat box shaped, having a substantially flat, rectangular or square front wall or panel  27  (typically referred to as the transformer front panel or plate  27 ), a substantially flat, rectangular or square rear wall or panel  29 , a pair of substantially flat, rectangular side walls or panels  31  extending between the front and rear plates  27 ,  29 , and a bottom panel  33  will all the various panels joined together to form the opened top, liquid-tight vessel  23 . The electrical connectors  19  of the transformer are mounted on the exterior face of the transformer front plate  27  with electrical conductors extending through the transformer front plate  27  between the electrical connectors  19  and the core/coil assembly inside the tank  21  as will now be apparent to those skilled in the art.  
         [0022]    The cover  25  is preferably designed to completely cover and close the opened top of the vessel  23 . The cover  25  may have a lip  34  around the outer edges thereof. The lip  34  is preferably down-turned around the rear and side edges of the cover  25 , and may be up-turned along the front edge of the cover  25 . The lip  34  reinforces and structurally strengthens the cover  25 , and plays an important role in preventing unauthorized removal of the cover  25  from the vessel  23  as will hereinbelow be explained. Bolts  35 , preferably carriage head bolts, extend through the edge of the cover  25  and through a flange  37  in the upper edges of the front, rear and side panels  27 ,  29 ,  31 . Nuts  39  are preferably used to secure the bolts  35  and fix the cover  25  to the vessel  23 . A gasket  41  may be provided between the cover  25  and the flange  37 .  
         [0023]    The vessel  23  preferably has a reinforced portion at the opened top thereof. The reinforced portion may be formed by a channel, i.e., an outwardly opening, box or U-shaped section or channel  43 , extending around at least the upper edges of the rear and side panels  29 ,  31  of the vessel  23 , with the flange  37  forming the upper leg or arm of the channel  43 . The channel  43  strengthens the vessel  23  sufficiently and acts as a structural member to allow for the use of thinner material than what has been traditionally used for such transformer tanks with removable covers. The box section or channel  43  also assists in keeping the top flange  37  of the vessel  23  straight, when looking along the length, giving better alignment with the cover  25  (e.g., between the apertures in the cover  25  and the flange  37  for the shaft of the bolts  35 ) than traditional designs. When used to secure the cover  25  to the vessel  23 , the nuts  39  and distal ends of the bolts  35  are located with a cavity  45  formed by the channel  43 , and the channel  43  will play an important role in preventing unauthorized removal of the cover  25  from the vessel  23  as will hereinbelow be explained.  
         [0024]    The cabinet  11  includes a wiring cabinet or compartment  47 , sometimes referred to as the air compartment or cabinet, covering at least a portion of the transformer tank front plate  27  for enclosing the electrical connectors  19  mounted on the exterior face of the transformer front plate  27 . The wiring compartment  47  includes a cover or hood  49 , a door assembly  51 , a first side panel  53 , a second side panel  55 , first hinge means or structure  57  joining the door assembly  51  and the first side panel  53  together to allow the door assembly  51  to pivot relative to the first side panel  53 , second hinge means or structure  59  joining the door assembly  51  and the second side panel  55  together to allow the door assembly  51  to pivot relative to the second side panel  55 , third hinge means or structure  61  joining the first side panel  53  and the transformer tank front plate  27  together to allow the first side panel  53  to pivot relative to the transformer tank front plate  27 , and fourth hinge means or structure  63  joining the second side panel  55  and the transformer tank front plate  27  together to allow the second side panel  55  to pivot relative to the transformer tank front plate  27 . A partition  64  may extend from the transformer front plate  27  into the interior of the wiring compartment  47  to divide the interior of the wiring compartment  47  into high and low voltage areas. The wiring compartment  47  preferably includes fifth hinge means or structure  65  joining the hood  49  and the transformer tank front plate  27  together (via a U-shaped hinge channel  66  which extends across the transformer tank front plate  27  and is secured to the flange  37  of the transformer tank front plate  27  using the bolts  35  and nuts  39  assemblies or formed as part of the front plate  27 ) to allow the hood  49  to pivot relative to the transformer tank front plate  27 . The door assembly  51  preferably includes a first door panel  67  joined to the first side panel  53  by the first hinge means or structure  57  and a second door panel  69  joined to the second side panel  55  by the second hinge means or structure  59 .  
         [0025]    The first and second hinge structures  57 ,  59  allow the door assembly  51  (i.e., the first and second door panels  67 ,  69 ) to open and close in the typical manner. The third hinge structure  61  allows the first side panel  53 , with the first door panel  67  attached thereto, to swing between fully opened and closed positions. The fourth hinge structure  63  allows the second side panel  55 , with the second door panel  69  attached thereto, to swing between fully opened and closed positions. The fifth hinge structure  65  allows the hood  49  to open and close in the typical manner.  
         [0026]    The overall effect of the hinge structures  57 ,  59 ,  61 ,  63 ,  65  is to allow the wiring compartment  47  to be opened by authorized personnel to allow the interior of the wiring compartment  47  to be totally exposed on all three sides and the top. This allows utility linemen, etc., to work on the electrical connectors  19  and other wiring within the wiring compartment  47  without any obstructions caused by the compartment  47 . The hood  49 , side panels  53 ,  55 , hinge structures  57 ,  59 ,  61 ,  63 ,  65 , and door panels  67 ,  69  are preferably constructed to enable easy removal of the hood  49 , either or both door panels  67 ,  69  only, or either or both door panels  67 ,  69  and associated side panels  53 ,  55 , etc.  
         [0027]    A U-shaped sill  70  preferably sits on the pad  15  and extends from the transformer front plate  27  below the side panels  53 ,  55  and door panels  67 ,  69  of the wiring compartment  47 . The sill  70  is preferably bolted or otherwise detachably secured to the bottom of the transformer front plate  27 . The sill  70  allows the side panels  53 ,  55  to swing open without scrapping on the pad  15  or the ground, and to function as doors.  
         [0028]    The hood  49 , side panels  53 ,  55 , hinge structures  57 ,  59 ,  61 ,  63 , and door panels  67 ,  69  of the wiring compartment  47 , and the U-shaped sill  70 , etc., are preferably designed and constructed so that with the wiring compartment  47  closed, the various parts form tight fits with multiple bends to resist wire entry and meet the tamper requirements outlined in ANSI C57.12.28-1999. A standard locking means  71  including a handle  72  is provided to lock the wiring compartment  47  in the fully closed position. The hood  49  and side panels  53 ,  55  are preferably designed so that the hood  49  must be raised before the side panels  53 ,  55  can swing open.  
         [0029]    The cabinet  11  preferably includes tamper-proof securing means  73  for preventing or hindering unauthorized removal of the transformer tank cover  25  from the open top of the transformer tank vessel  23 . The tamper-proof securing means  73  includes a shield member  75  for blocking unauthorized access to the nuts  39  securing the bolts  35 , and thus the cover  25 , to the opened top vessel  23 . The shield member  75  is designed to fit into or be positioned within the channel  43  of the vessel  23  to block unauthorized access to the nuts  39 . The shield member  75  may be U-shaped in cross section (see FIG. 7), and U-shaped in plan, having a back portion  77  extending within the cavity  45  of the channel  43  along the rear panel  29  of the vessel  23  and side members  79  for extending within the cavity  45  of the channel  43  along both side panels  31  of the vessel  23 . As will be noted from FIG. 7, depending on the specific design of the channel  43  and shield member  75 , the lip  34  of the cover  25  may also play part in limiting access to the nuts  39 . The shield member  75  is secured to the transformer enclosure  11  in a manner that access into the interior of the wiring compartment  47  is required to remove the shield member  75 . For example, the shield member  75  may be affixed to the transformer front plate  27  by way of weld studs or bolts  81  extending through an end plate  83  on each side portion  79  of the shield member  75  and then through the transformer front plate  27 , and hardware or nuts  85  affixed to each bolt  81  within the interior of the wiring compartment  47  (see FIG. 8), which can be removed only after gaining access through the door assembly  51  of the wiring compartment  47 , thereby limiting access to the nuts  85  to authorized personnel having a key or code, etc., to the locking means  71 .  
         [0030]    Construction and operation of the padmount transformer enclosure  11  should now be apparent to those skilled in the art. The vessel  23  of the transformer tank  21  can be constructed as a liquid tight enclosure out of relatively thin sheet metal due to the box or U-shaped reinforcement provided by the channel  43 . In addition, due to the strength of the design, some of the traditional tank stiffening, including the need for additional stiffening gussets around the upper section of the tank  21 , can be eliminated, especially when used with external cooling fins. Lift lugs  87  may be welded or otherwise fixed to the vessel  23  to allow the transformer enclosure  11  to be easily moved in the typical manner. The hood  49 , side panels  53 ,  55 , and door panels  67 ,  69  of the wiring compartment  47 , and the sill  70  are preferably constructed out of sheet metal with multiple bends, etc., at the edges so that when the wiring compartment  47  is closed, the hood  49 , side panels  53 ,  55 , and door panels  67 ,  69 , and sill  70  form tight fits with one another to resist wire entry and preclude tampering, etc.  
         [0031]    Although the present invention has been described and illustrated with respect to a preferred embodiment and a preferred use therefor, it is not to be so limited since modifications and changes can be made therein which are within the full intended scope of the invention.