Patent Publication Number: US-6220901-B1

Title: Electric motor terminal board assembly

Description:
FIELD OF THE INVENTION 
     This invention relates generally to electric motors and more particularly, to a terminal board assembly for connecting motor leads to power line leads. 
     BACKGROUND OF THE INVENTION 
     Electric motors sold for use in the United States often include multiple loose wire leads for connecting to the power line connecting leads. The wire leads and the power line connecting leads are connected, typically with wire nuts, in a conduit or terminal box attached to the motor housing. European standards require, however, that electric motors include a six stud connector block with connecting bars for setting “Y” or “Delta” voltage selections, mounted in the conduit box. The motor leads are attached to the connector block, usually with eyelet type connectors. To connect the motor to the power line, the power line leads must be connected to the proper terminal studs. 
     Electric motors manufactured to European standards using commercially available European type connector blocks with eyelet connectors are expensive to manufacture. Increased labor costs are incurred due to the increased time needed to mount the terminal block and to connect the leads using the eyelet connectors. 
     It would be desirable to provide a motor connector block meeting European standards that can be easily and quickly installed in the motor terminal box. It would further be desirable to provide a connector block that can be easily and quickly removed from the motor terminal box for service or replacement. 
     SUMMARY OF THE INVENTION 
     These and other objects may be attained by a terminal board assembly configured to mount inside an electric motor conduit box and including a terminal board and a mounting bracket. The terminal board includes six terminal studs and three connecting bars extending between terminal studs configured to meet the European standards for electric motor connections to power line leads. Quick connect spade type connectors are coupled to the six terminal studs adjacent the bottom of the terminal board to facilitate quick and easy connection of the wire connection leads of an electric motor. The terminal studs and connecting bars permit a choice of “Y” or “Delta” voltage connections to the electric motor. The terminal board also includes a first and a second slot positioned at, and parallel to, opposing ends of the board for securing the terminal board to the mounting bracket as described below. 
     The mounting bracket includes a base portion and first and second side portions depending from opposing ends of the base portion. An engaging portion extends from each side portion and is configured to extend through the slots positioned at the opposing ends of the terminal board. Each engaging portion includes a retaining tab configured to engage the terminal board. The base portion of the mounting bracket includes at least one mounting opening for attaching the bracket to the electric motor conduit box. 
     To install the terminal board assembly in an electric motor conduit box, the mounting bracket is mounted inside the conduit box with mounting screws. The terminal board is then installed by positioning the board so that the slots in the board are positioned over the engaging portions of the mounting bracket. The terminal board is then pushed down onto the bracket so that the bottom of the board contacts the edge of the bracket side portions adjacent the base of the engaging portions, and the retaining tabs engage the board thereby securing the board in place. The motor wire leads may be connected to the board either before or after the board is secured in the mounting bracket. 
     The above-described terminal board assembly includes quick connect terminal connectors for quick and easy connection of the electric motor wire connection leads to the board. Additionally, the mounting bracket permits the terminal board to “snap in place” in the conduit box without the use of additional fasteners. The “snap in place” mounting bracket permits easy installation and easy removal of the terminal board for possible service, replacement, or installation of the power line connection leads. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a terminal board assembly in accordance with one embodiment of the present invention mounted in an electric motor conduit box. 
     FIG. 2 is a front cross sectional view of the terminal board assembly and electric motor conduit box shown in FIG.  1 . 
     FIG. 3 is a side cross sectional view of the terminal board assembly and electric motor conduit box shown in FIG.  1 . 
     FIG. 4 is a perspective view of the mounting bracket of the terminal board assembly shown in FIG.  1 . 
     FIG. 5 is a top view of a terminal board in accordance with another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1,  2 , and  3 , a terminal board assembly  20  in accordance with one embodiment of the present invention is shown mounted inside an electric motor terminal or conduit box  22 . Conduit box  22  includes a base member  24  and a cover member  26 . Base member  24  has the general shape of an open top box and includes a bottom  28 , four sides  30 A,  30 B,  30 C, and  30 D, and a sealing flange  32  extending from sides  30 A,  30 B,  30 C, and  30 D. An opening  34  (see FIGS. 1 and 3) extends through bottom  28  of base member  24  to permit electric motor lead wires (not shown) to enter conduit box  22 . Another opening  36  (see FIG. 3) extends through side  30 A to permit power line connection wires (not shown) to enter conduit box  22 . Mounting screws  38 A and  38 B extend through bottom  28  to secure conduit box  22  to an electric motor (not shown). A ground screw  40  (see FIGS. 1 and 3) extends through bottom  28  of base member  24 . Cover  26  is configured to be secured to base member  24  and includes a sealing flange  42  configured to mate with sealing flange  32  of base member  24 . Cover  26  is mounted to base member  24  with cover mounting screws  44 A and  44 B (see FIG. 2) which extend through sealing flanges  32  and  42  at opposing ends of conduit box  22 . In another embodiment, conduit box  22  may be remotely mounted from the electric motor (not shown). In such a configuration, the electric motor wire leads are routed through a conduit extending between the motor and conduit box  22 . 
     Terminal board assembly  20  includes a terminal board  46  and a mounting bracket  48 . Terminal board  46  is configured to fit inside conduit box  22  and includes a first surface  52  and a second surface  54 . Elongate slots  56 A and  56 B are located at opposing ends  58  and  60  of terminal board  46  (see FIG.  1 ). Slots  56 A and  56 B are configured to engage mounting bracket  48 , and are parallel to ends  58  and  60 . Terminal board  46  includes six terminal studs  62 A,  62 B,  62 C,  64 A,  64 B, and  64 C. Terminal studs  62 A,  62 B, and  62 C are threaded type studs, and include nuts  65 A,  65 B, and  65 C. Terminal studs  64 A,  64 B, and  64 C are threaded type studs and include nuts  66 A and  68 A,  66 B and  68 B, and  66 C and  68 C respectively (see FIG.  2  and  3 ). Quick connect spade type terminals  70 A,  70 B,  70 C,  72 A,  72 B, and  72 C are coupled to terminal studs  62 A,  62 B,  62 C,  64 A,  64 B, and  64 C respectively and are positioned adjacent to second surface  54  of terminal board  46 . Of course, quick connect terminals  70 A,  70 B,  70 C,  72 A,  72 B, and  72 C may be any suitable type quick connect terminal. Connecting bars  74 A,  74 B, and  74 C extend between and connect to studs  62 A and  64 A, studs  62 B and  64 B, and studs  62 C and  64 C, respectively (see FIG.  1 ). This configuration provides a “Delta” voltage connection to the electric motor. Different configurations of connecting bars  74 A,  74 B, and  74 C between terminal studs  62 A,  62 B,  62 C,  64 A,  64 B, and  64 C, permit a choice of “Y” or “Delta” voltage connections to the electric motor. 
     Referring to FIG. 4, mounting bracket  48  is configured to fit inside conduit box  22  and includes a base portion  76  and side portions  78 A and  78 B depending from opposing sides of base portion  74 . Side portions  78 A and  78 B include first ends  80 A and  80 B, and second ends  82 A and  82 B, respectively. Engaging portions  84 A and  84 B extend from second ends  82 A and  82 B of side portions  78 A and  78 B respectively and are configured to extend through the slots  56 A and  56 B. Engaging portions  84 A and  84 B include retaining tabs  86 A and  86 B respectively which are configured to engage terminal board  22 . Side portions  78 A and  78 B are wider than engaging portions  84 A and  84 B and include edges  88 A and  88 B adjacent to engaging portions  84 A and  84 B. Mounting opening  90  extends through base portion  76 . Mounting screw  38 A (shown in FIG. 3) extends through mounting opening  90  and secures mounting bracket  48  to bottom  28  of conduit box  22 . Mounting bracket  48  may be fabricated from sheet metal. Some non-limiting examples of sheet metal include, for example, galvanized steel, aluminum, and stainless steel. 
     To install terminal board assembly  20  in electric motor conduit box  22 , mounting bracket  48  is mounted to conduit box  22  with mounting screw  38 A. Terminal board  46  is then installed by positioning board  46  so that slots  56 A and  56 B are positioned over engaging portions  84 A and  84 B of mounting bracket  48 . Terminal board  46  is then pushed down onto bracket  48  so that second surface  54  of board  46  contacts bracket edges  88 A and  88 B of side portions  78 A and  78 B, and bracket retaining tabs  86 A and  86 B engage board  46  thereby securing board  46  in place. Typically, the electric motor wire leads (not shown) are connected to terminal board  46  before board  46  is secured in mounting bracket  48 . Particularly, the motor wire leads are connected to the appropriate quick connect terminal connectors  70 A,  70 B,  70 C,  72 A,  72 B, and  72 C. However, the motor wire leads may also be connected to terminal board  46  after board  46  is secured in mounting bracket  48 . 
     Terminal board  46  may be easily removed from conduit box  22  for possible service or to connect power line connection leads (not shown). Particularly, terminal board  46  is removed from box  22  by disengaging retaining tabs  86 A and  86 B from board  46  and sliding board  46  off engaging portions  84 A and  84 B of mounting bracket  48 . 
     FIG. 5 illustrates an alternative embodiment of terminal board  46  which includes notches  92 A and  92 B located at ends  58  and  60  respectively in place of slots  56 A and  56 B. FIG. 5 also illustrates the configuration of connecting bars  74  for a “Y” voltage connection. Terminal board  46  is configured for a “Y” voltage connection to the electric motor. Particularly, connecting bars  74 A and  74 B are connected between studs  62 A and  62 B, and  62 B and  62 C respectively to provide for a “Y” voltage connection to the electric motor. 
     The above-described terminal board assembly  20  includes quick connect terminal connectors  70 A,  70 B,  70 C,  72 A,  72 B, and  72 C for quick and easy connection of the electric motor wire connection leads to board  46 . Additionally, assembly  20  includes mounting bracket  48  that permits terminal board  46  to “snap in place” in conduit box  22  without the use of additional fasteners. “Snap in place” mounting bracket  48  permits easy installation and easy removal of terminal board  46  for possible service or installation of the power line connection leads. 
     From the preceding description of various embodiments of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.