Patent Application
20080055025
Referring to the exemplary drawings wherein the elements are numbered alike in the accompanying Figures:
An embodiment of the invention provides a resistance wire having a single piece snap fit terminal, which is easy to manufacture and assemble. There are no housings and no additional connecting terminals used in conjunction with the resistance wire. The resistor terminal is directly snapped into the main terminal of the contactor. As compared with the resistance wire disposed within a housing, use of the snap fit terminal allows for a part count reduction and the avoidance of additional plastic housing parts. Use of a separate plastic module including complicated molds and extended terminals, an intermediate plastic housing, terminals, and connecting screws for housing the resistor wire and for terminating the resistor wire onto the main terminal of the contactor, may all be avoided.
Referring now to
In an embodiment, each set of the auxiliary terminals 210 is electrically connected to the respective set of the main terminals 200 via a resistance wire 250, such that each set of the auxiliary terminals 210 is electrically connected in parallel with each respective set of the main terminals 200. In an embodiment, each resistance wire 250 is electrically insulated. In an embodiment, the electrical insulation comprises an insulation sleeve 249 that is applied to the exterior of each resistance wire 250.
In an embodiment, the resistance wires 250 each comprise a plurality of loops 251. The total length of the resistance wire 250 is determined by a desired resistance value. The loops 251 are configured to reduce the overall length between the auxiliary terminals 210 and the main terminals 200 required for the specific length of resistance wire 250 having the desired resistance value.
In an embodiment, the loops 251 are each configured and disposed above the openings of the main terminals 200 to provide unobstructed access by the end user to the main terminals 200. Disposition of the loops 251, absent a housing, above the main terminal 200 openings allow for simplified installation of the phase conductors 205, and also provide for an enhancement of the dissipation of any heat that may be generated by the phase conductors 205. The loops 251 are disposed such that each resistance wire 250 is exposed to the same ambient environment as the auxiliary switch 120, thereby enhancing the dissipation of any heat that may be generated by the resistance wire 250 in operation. In an alternate embodiment, the loops 251 are disposed such that each electrically insulated resistance wire 250 is exposed to the same ambient environment as the auxiliary switch 120.
While an embodiment of the invention has been depicted having a three phase switching apparatus, it will be appreciated that the scope of the invention is not so limited, and that invention also applies to other switching apparatuses having different numbers of phases, such as one, two, four, or more distinct phase paths, for example.
Referring now to
Referring now to
Referring now to
While an embodiment of the invention has been depicted having a second terminal 270 with two retention hooks 300, it may be appreciated that the scope of the invention is not so limited, and that the invention also applies to other second terminals 270 having different numbers of retention hooks 300, such as one, three, four, or more retention hooks, for example.
Referring now to
Referring now to
While an embodiment of the invention has been depicted to provide a snap fit by having protrusions extending from the retention hooks 305, 306, it will be appreciated that the scope of the invention is not so limited, and that the invention also applies to alternate configurations to provide a snap fit, such as ribs, knurls, or protrusions extending from the wire clamp into recesses in the bottom of the retention hooks, for example.
Referring now to
The embodiments of the second terminal 270 described above are configured to ensure that the second terminal 270 and the terminal connector 201, 206 do not become disengaged or dislodged in response to connecting the phase conductor 205 to the main terminal 200. Each second terminal 270 is configured to withstand at least 10 kilograms of pullout force for at least one minute without becoming disengaged from the main terminal 200. Pullout force indicates a force that is applied directly to the resistance wire 250 to disengage it from the main terminal 200, as may be illustrated by the direction line F in
As disclosed, some embodiments of the invention may include some of the following advantages: improved integrity of the resistor termination to ensure that the resistance wire remains connected with the main terminal; increased available space for the phase conductor to be terminated; improved resistance wire and phase conductor heat dissipation; reduced total cost resulting from fewer parts; and, increased ease of assembly using top-down assembly methods.
While the invention has been described with reference to exemplary embodiments, 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 or only mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
