Abstract:
A universal electrical connector is incorporated into the electric power distribution network of a motor control center, switchboard, or switchgear between vertical bus conductors and the power line inlet. The connector in the form of substantially a single metal casting is configured to connect the power line with the control center internal electrical distribution conductors without requiring additional connectors.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electrical connectors and more particularly relates to an electrical connector for attaching to a vertical bus bar. 
     Motor control centers perform various protection and control functions in industrial settings. In such motor control centers, three-phase electric power is fed from main conductors in electric power distribution mains (mains) to the motor control center. Within the motor control center housing, internal electric power is fed from the mains to the horizontal and vertical bus conductors (bus bars). Electrical power is fed through the bus bars to internal electrical components mounted within drawers or buckets, which slide in and out of the motor control center housing. The buckets contain electrical components such as one or more circuit breakers, starters, overload protectors, or pilot devices. 
     Horizontal bus bars, which are typically positioned in the upper or lower section of the control center cabinets, are arranged within the motor control center to connect the vertical bus bars. Each vertical bus bar forms a plane substantially perpendicular to the back wall of the motor control center for electrical connection to a power inlet from the mains and for carrying current to the electrical components that are arranged in the buckets. Each bucket has a plurality of stabs extending from the back of the bucket for electrically connecting the electrical components within the bucket with the vertical bus bar. Each stab includes opposing prongs biased toward each other to contact either side of a bus bar, whereby the electrical connection with the bus bar. In addition, the connection between the buckets and the bus bars can be accomplished using clips, which slidably accept the bus bars. 
     There is a need, however, for a strong and simple apparatus to connect incoming power cables with a vertical bus bar arrangement within a motor control center. Typically, a phase barrier is disposed between each power cable phase to prevent short circuiting by one phase coming in contact with another. The three phase power cables need to be connected securely to the vertical bus bars regardless of whether a phase barrier arrangement is used or not and strong enough to withstand levels and the tendency for devices to disengage at higher amperage readings without the need for excessive hardware. 
     BRIEF SUMMARY OF THE INVENTION 
     The above needs are filled by providing in a motor control center, or alternatively, in either a switch gear or switchboard, an electrical connector electrically connecting a bus bar to a power source comprising a main body portion having a first end and a second end, a base plate disposed substantially perpendicular to said first end of the body portion and secured to the base plate. The base portion is electrically connected to least one lug. The electrical connector further comprises a U-shaped member attached to the second end of the main body portion and includes legs configured to engage the bus bar through which an electrical contact can be made for supplying electrical current to the bus bar. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a motor control center; 
     FIG. 2 is a front plan view of the vertical bus barrier within one section of a motor control line up; 
     FIG. 3 is a front plan view showing horizontal and vertical bus bars with respect to the bus barriers; 
     FIG. 4 is a front plan view of a three-section motor control line up; 
     FIG. 5 is top view of a vertical bus power connector; 
     FIG. 6 is a cross section view of a vertical bus power connector in FIG. 5, Section A—A; and 
     FIG. 7 is a front perspective view of a vertical bus power connector. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In an exemplary embodiment and referring now to FIG. 1, a motor control center  10  is illustrated. An enclosure cabinet  12  receiving electrical current includes openings  14  to accept incoming power cables  15 . A plurality of drawers or buckets  16  is also included within cabinet  12 . Buckets  16  contain various electrical components (not shown) such as one or more circuit breakers, starters, overload protectors, or pilot devices. A wing plate  18  (shown by phantom lines) is vertically disposed at the rear portion of cabinet  12 . Wing plate  18  can be disposed across the entire rear portion of cabinet  12  or a portion thereof. It will be appreciated by one skilled in the art that the incoming power cables  15  may be arranged to enter a lower portion of cabinet  12  (FIG. 2) and that the specific configuration of wing plate  18  and various buses thereon may differ depending on the specific design needs. Horizontal or vertical main bus bars (not shown) are located within cabinet  12 . Electrical components within buckets  16  are generally protected by one or more circuit breakers  22 . 
     Turning to FIG. 2, a vertical bus barrier  111  is shown within one section of motor control center  10 . Vertical bus barrier  111  is used to insulate the vertical bus bars  160 , three shown, from buckets  16  that slide into the cabinets. Typically, the vertical bus bars  160  are substantially flat, having a rectangular cross-sectional shape, and having slim profile while exposed through the barrier  111  as shown at  162  where connection is made to incoming power cables  15 . That is, the thickness of the vertical bus bars  160  is shown at  162 . FIG. 2 depicts one incoming power cable  15  having power cable conductor  17  received in hole  440  of a lug  100  and fixed to the lug with a setscrew (not shown). The lug  100  is attached to a face plate  116  that is attached to the vertical bus power connector (not shown) electrically connecting the power cable  15  to a vertical bus bar  160 . 
     FIG. 3 shows horizontal and vertical bus bars  170  and  160  within section  122  of motor control center  10 . It can be seen that one vertical bus bar  160  is bolted to each horizontal bus bar  170  at connecting sections  180 . 
     FIG. 4 shows three sections  122 ,  194  and  196  of motor control center  10 . motor control line-up  190 . Vertical bus bars  160  are shown only in sections  122  and  194 , not in section  196 . The horizontal bus bars  170 , however, pass through all three sections  122 ,  194  and  196  electrically connecting the vertical bus bars  160  from section  122  and  194 . The flow of electrical current is from incoming cables (FIG. 2) to the vertical bus bar connectors to the vertical bus bars  160  in section  122  to the horizontal bus bars  170  at connecting sections  180 . The electrical current then proceeds from horizontal bus bars  170  to vertical bus bars  160  in sections  194  and  196  and then to electrical components mounted within buckets  16  (not shown). 
     FIG. 5 shows a top view of a vertical bus bar connector  300 . A C-shaped wing plate  200  is disposed on either side of cabinet  12 . One end of each left and right wing plate  18  is attached to C-shaped wing plate  200  towards the rear of cabinet  12 , and a vertical bus barrier  111  is connected to wing plates  18  at the opposite end. The bus barrier  111  has cutouts  240  to allow a U-shaped member  312  at one end of the bus bar connector  300  to pass through. Three vertical bus bars  160  representing three phases of a power distribution system are disposed along a vertical length inside cabinet  12  and each vertical bus bar  160  is coupled to the U-shaped member  312  of a bus bar connector  300 . The U-shaped member  312  receives bus bar  160  such that legs  324 ,  326  (FIG. 7) forming either side of inner portion of U-shaped member  312  are disposed on, and form an electrical connection with opposing sides of bus bar  160 . The bus bar connector  300  extends through the cutout  240  in the vertical bus barrier  111  and then through an opening  322  in an insulative barrier  310  that is disposed on wing plates  260 , which in turn are disposed on the C-shaped wing plates  200 . Phase barriers  280  are perpendicularly disposed on the insulative barrier  310  between the bus bar connectors  300  and extend to the front of cabinet  12  to prevent any potential short circuit between the phases. A main body portion  314  of bus bar connector  300  extends from U-shaped member  312  towards the front of cabinet  12  through vertical bus barrier  111  cutouts  240  and the openings  322  in the insulative barrier  310 . Main body portion  314  is substantially rectangularly shaped. It should be noted that the core of a current transformer  360  for each phase may be mounted on the insulative barrier  310  surrounding each bus bar connector  300 , as shown, thus allowing the detection of current flow in each of the phases. At the other end of a bus bar connector  300 , a base plate  302  is disposed on main body portion  314  and perpendicularly oriented to the main body portion  314 . The base plate  302  comprises at least one opening for attaching either or both a face plate  116  and at least one lug (not shown). 
     Referring to FIG. 6, the insulative barrier  310  is formed from two pieces  320 ,  321  with each piece having an opening  322  to receive the main body portion  314  of the bus bar connector  300 . The insulative barrier  310  is formed from a two-piece assembly to allow the insulative barrier  310  to be installed onto the cabinet  12  after connectors  300  have been secured to vertical bus bars  160 . FIG. 6 also shows the insulative barrier  310  mounted to wing plates  260  and having phase barriers  280  (phantom lines) perpendicularly attached to separate each phase. 
     Turning to FIG. 7, the bus bar connector  300  is shown with a lug  100  and a section of a vertical bus bar  160 . The U-shaped member  312  receives bus bar  160  such that legs  324 ,  326  are configured to form an inner portion  328  of U-shaped member  312 , and allow an electrical connection with opposing sides  342  of bus bar  160 . Furthermore, an interference fit between legs  324 ,  326  of U-shaped member  312  and bus bar  160  is further accomplished when a leading edge  162  of the bus bar  160  connecting to the U-shaped member  312  is tapered and received between legs  324 ,  326 . As bus bar  160  is further inserted between legs  324 ,  326 , an interference fit is created between bus bar  160  and legs  324 ,  326 . Holes  364  disposed on bus bar  160  are aligned with holes  364  in U-shaped member  312  when bus bar  160  is fully inserted. Bolts, rivets, or the like are then placed through the holes  364  to secure bus bar  160  between legs  324 ,  326  of U-shaped member  312 . 
     A lug  100  is depicted in FIG. 7 comprising at least one hole  420  at one end for fastening to either the base plate  302  or a face plate  116  of bus bar connector  300  and a threaded opening  430  at the other end to receive a set screw, or the like (not shown). Lug  100  further comprises an opening  440  perpendicular to the threaded opening  430  for electrically receiving a power cable conductor  17  and held in place with the set screw, or the like (not shown). A ledge  402  of lug  100  will rest on a ledge  318  of a face plate  116  or ledge  304  of base plate  302  to prevent twisting of the lug  100 , thus limiting any short circuit potential. The lug may be flipped or turned 180 degrees so as to rest on opposite ledges of the above referenced elements to receive a power cable  15  from an opposite direction. The lug  100  is electrically connected to the base plate  302  of connector  300  with alignment of holes  420  of lug  100  and holes  432  of base plate  302 . Bolts, rivets, or the like  410  are then placed through the aligned holes  420  and  432  to secure lug  100  to base plate  302 . 
     The face plate  116  may be fastened with typically two threaded bolts  410  to the base plate  302  to cross brace at least one lug  100 , which would reduce potential movement of a lug  100  that in turn could produce a short circuit if caused to contact another phase conductor. The face plate  116  having openings  422  aligned with the holes  420  of the lug  100  and holes  432  of base plate  302  is shown for attachment to the base plate  302  to offer cross brace support for the lug  100 . 
     The flow of electrical current utilizing a vertical bus bar connector  300  is described with reference to FIG.  7 . Electric current flows from incoming power cable  15  to power cable conductor  17  that is held in place with the set screw, or the like in opening  440  of lug  100 . The electric current flows from lug  100  to base plate  302  by electrical connection utilizing aligned holes  432  on base plate  302  with holes  420  of lug  100 . The electrical current translates from the base plate  302  to the legs  324 ,  326  of the U-shaped member, as connector  300  is substantially made of a one-piece electrically conductive material, such as copper. The electrical current flows from legs  324 ,  326  to bus bar  160  caused by an interference fit between legs  324 ,  326  disposed on either side of bus bar  160  and furthered with an alignment of holes  364  to permit bolting or riveting, or the like to secure an electrical connection. 
     The present invention eliminates the need for more expensive fasteners by minimizing the number of parts necessary to make a simple and strong connection between a power cable and a bus bar. Using the vertical bus bar connector is cost effective, as it is a single fastener and requires no special assembly tools to install in a motor control center, a switch board, or a switch gear assembly using standard bolt type hardware and is capable of withstanding higher amperages without disengaging. The nut and bolt fastening design of the connector  300  to both the bus bar  160  and the power cable conductor  17  via the lug  100  shown in FIG. 7 essentially eliminates the possibility of short circuiting between the three phases by a simple strong connection reducing the risk for a short circuit between the phases regardless of whether a phase barrier is utilized. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.