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US 4,675,641 AGranted
Rating plug for molded case circuit breakers
AssigneeGeneral Electric Company
InventorsThomas G. Hampton, James M. Mitsch, Joseph M. Palmieri, David S. Parker, James I. Smith
Life of this patent
Estimating the term…
Abstract
A selectable rating plug allows a standard molded case circuit breaker design to be used over a wide range of ampere ratings. The rating plug is used to control the thermal load on the thermally responsive trip element within the breaker. Movement of the thermally responsive element articulates the breaker trip mechanism in response to predetermined overload conditions to interrupt circuit current.
Claims22
A molded case electric circuit breaker having adjustable ampere rating comprising:
- a plastic case and a cover;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts on said case, one of which being connected with said line terminal for reciving circuit current;
- an operating mechanism within said case connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined circuit current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said circuit current through said contacts reaches said predetermined circuit current;
- a heater element electrically in series between said contacts and arranged adjacent said thermally responsive element for providing temperature increase to said thermally responsive element in proportion to said circuit current, said heater element comprising an elongated resistive strap;
- and
- a rating plug having a defined ampere rating positioned adjacent said heater element and electrically connected in series with said heater element and said contacts for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said predetermined current, said rating plug comprising a selectable electrical resistance arranged a selectable distance along said heater element.
5 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- a rating plug having a defined ampere rating proximate said thermally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said current, said rating plug comprising a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element;
- and
- receptacle means comprising a pair of adjacent thermally conductive members, one of said thermally conductive memberts being arranged along said thermally responsive element, said rating plug being inserted between said thermally conductive members to provide a selectable heat sink to said thermally responsive element.
5 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- and
- a rating plug having a defined ampere rating proximate said thermally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said current, said rating plug comprising a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element, said rating plug being electrically connected in series with said thermally responsive element and said contacts.
4 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- and
- a rating plug having a defined ampere rating proximate said theremally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said current, said rating plug comprising a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element, said rating plug being electrically connected in parallel with said thermally responsive element.
4 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- and
- a rating plug having a defined ampere rating proximate said thermally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said current, said rating plug comprising a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element, said rating plug comprising at least two metals of different thermal diffusivities arranged in a plane, the plane of said materials being oriented with respect to said receptacle for providing said selectable thermal diffusivity to said rating plug.
4 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- and
- a rating plug having a defined ampere rating proximate said thermally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in response to said current, said rating plug comprising a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element, said rating plug comprising a circular configuration of a plurality of metals of different thermal diffusivities arranged around a center point, said circular configuration being rotatable within said receptacle means for varying said selectable thermal diffusivity and said time for said thermally responsive element to reach said predetermined temperature.
4 more elements
A molded case electric circuit breaker having adjustable ampere ratings comprising:
- a plastic cover and a plastic case;
- a line terminal and a load terminal mounted on said case;
- a pair of separable contacts within said case one of which being connected with said line terminal;
- an operating mechanism connected with the other of said contacts for opening said contacts upon the occurrence of a predetermined current through said contacts;
- a thermally responsive element proximate said operating mechanism for articulating said operating mechanism when said current through said contacts reaches said predetermined current;
- and
- a rating plug having a defined ampere rating proximate said thermally responsive element for controlling the time for said thermally responsive element to reach a predetermined temperature in respnse to said current, said rating plug comprisin a metal element of selectable thermal diffusivity arranged a selectable distance along said thermally responsive element, said rating plug comprising a cruciform configuration of a plurality of metals of varying thermal diffusivities wherein said cruciform is inserted within said receptacle means for varying said selectable thermal diffusivity of said rating plug and said time for said thermally responsive element to reach said predetermined temperature.
4 more elements
Dependencies are inferred from the claim text.