Automatic molded case circuit breaker with time-delay overcurrent tripping

Claim 2

An electric circuit breaker comprising: a. at least one pair of relatively separable contacts; b. operating mechanism for operating said contacts between open and closed circuit positions respectively, said operating mechanism including a releasable member and means normally latching said releasable member against movement, said releasable member being releasable to cause automatic opening of said contacts by said mechanism; c. first current responsive means responsive to relatively low abnormal currents through said circuit breaker; d. means connecting said first current responsive means to said latch means for causing the release of said latch means upon the occurrence of predetermined relatively low overload currents through said circuit breaker; e. second current responsive means responsive to relatively high overload currents through said circuit breaker; f. switch means operated by said second current responsive means; g. electrically operated means connected to said switch means, said electrically operated means comprising means for releasing said latch upon actuation of said Electrically operated means; h. circuit means interconnecting said switch means and said electrically operated means, said circuit means including timedelay means for introducing an accurately controlled short-time delay between the actuation of said switch and the operation of said latch, whereby said circuit breaker may be utilized with other circuit breakers in a system in which circuit breakers operate in a predetermined time sequence.

Claim 3

An electric circuit breaker as set forth in claim 1 wherein said circuit breaker also comprises conductor means connecting said first and second current responsive means and electromagnetically permeable shielding means between said conductor means and at least a portion of said second current responsive means.

Claim 4

An electric circuit breaker as set forth in claim 1 wherein said first current responsive means comprises inverse-time characteristic current-responsive means and wherein said second current-responsive means comprises substantially instantaneous acting current-responsive means.

Claim 5

An electric circuit interrupter as set forth in claim 3 wherein said circuit breaker also comprises conductor means connecting said first and second current-responsive means and electromagnetically permeable shielding means between said conductor means and at least a portion of said second current responsive means.

Claim 6

An electric circuit breaker as set forth in claim 1 wherein said electrically operated means for releasing said latch comprises a solenoid including a winding and a spring-biased plunger normally held in retracted position when said solenoid winding is energized and normally charged capacitance means, said capacitance means providing electrical power for said winding for a short time after the removal of said external power source by opening action of said electric switch.

Claim 7

An electric circuit breaker as set forth in claim 1, wherein said electrically operated means for releasing said latch comprises an electric solenoid having a winding and a spring-biased plunger biased for movement outwardly of said winding, said plunger when released from said winding being moved by said spring-biasing means to engage said latch and cause the release thereof, said circuit breaker also comprising: a. an electric relay including a winding and at least one pair of normally open contacts; b. electrical capacitance means; c. charging means for charging said capacitance from an external source of electric power; d. said switch means being connected electrically in series with said capacitance means and said external source of power; e. said relay winding being connected electrically in series with a predetermined resistance means and said capacitance, whereby said relay is normally energized by said external source of power when said switch means is in closed condition, to maintain said contacts in closed condition, and upon opening of said switch means said relay winding is disconnected from said external source of power and receives power from said capacitance through said resistance, said power lasting a predetermined time to provide a predetermined accurately controlled time-delay between the opening of said switch means and the opening of said relay contact; f. said relay contact being connected electrically in series with said electrically operated means, whereby said electrically operated means is operated upon opening of said relay contacts to cause release of said circuit breaker latch means.

Claim 8

An electric circuit breaker as set forth in claim 6 wherein said circuit also includes additional capacitance and resistance means connected electrically in series to form a series combination, said series combination being connected electrically in parallel with said electrically operated means through said switch means, whereby said second capacitance and resistance combination provides power to said solenoid for a length of time at least as long as the aforesaid time delay provided by said time-deLay relay.

Claim 9

An electric circuit breaker comprising: a. a first generally rectangular insulating casing; b. at least one pair of relatively separable contacts supported in said insulating casing; c. operating means supported in said insulating casing for operating said contacts between open and closed circuit positions respectively; d. said operating mechanism including a releasable member releasable to cause automatic opening of said contacts and latch means normally restraining said releasable means in latched position; e. first current responsive means supported in said first insulating casing, means connecting said first current responsive means to said latch member whereby said first current-responsive means causes release of said latch member upon the occurrence of predetermined relatively low overload currents through said contacts; f. a second generally rectangular insulating casing having its cross-sectional dimensions substantially equal to said cross-sectional dimensions of said first insulating casing; g. second current responsive means mounted in said second insulating casing and connected electrically in series with said contacts, said second current-responsive means being responsive to relatively high overload currents through said contact; h. electrical switch means supported in said second insulating casing for operation by said second current responsive means; i. an electric solenoid mounted in said first insulating casing and including an armature disposed and arranged to engage said latch member and cause release of said latch member upon the occurrence of predetermined electrical conditions in said solenoid; j. circuit means interconnecting said electric switch in said second insulating casing to said solenoid in said first insulating casing, said circuit means including time-delay means providing a predetermined accurately controlled time-delay between actuation of said switch means and operation of said solenoid means to cause release of said latch means, whereby said circuit breaker may be used in an electrical system with other circuit breakers to achieve opening in response to fault currents in a predetermined sequence.

Claim 10

An electric circuit breaker comprising: a. a first generally rectangular insulating casing; b. at least one pair of relatively separable contacts supported in said insulating casing; c. operating means supported in said insulating casing for operating said contacts between open and closed circuit positions respectively; d. said operating mechanism including a releasable member releasable to cause automatic opening of said contacts and latch means normally restraining said releasable means in latched position; e. first current responsive means supported in said first insulating casing, means connecting said first current responsive means to said latch member whereby said first current-responsive means causes release of said latch member upon the occurrence of predetermined relatively low overload currents through said contacts; f. a second generally rectangular insulating casing having its cross-sectional dimensions substantially equal to said cross-sectional dimensions of said first insulating casing; g. second current responsive means mounted in said second insulating casing and connected electrically in series with said contacts, said second current-responsive means being responsive to relatively high overload currents through said contact; h. electrical switch means supported in said second insulating casing for operation by said second current responsive means; i. an electric solenoid mounted in said first insulating casing and including an armature disposed and arranged to engage said latch member and cause release of said latch member upon the occurrence of predetermined electrical conditions in said solenoid; j. circuit means interconnecting said electric switch in said second insulating casing to said solenoid in said first insulating casing, said circuit means including time-delay means providing a predetermined accurately controlled time-delay between actuation of said switch means and operation of said solenoid means to cause release of said latch means, whereby said circuit breaker may be used in an electrical system with other circuit breakers to achieve opening in response to fault currents in a predetermined sequence.

Claim 11

An electric circuit breaker as set forth in claim 8 wherein said solenoid comprises a winding and a movable armature and means biasing said armature away from said winding and means connecting said armature to said latch means fur causing releasing movement of said latch means upon predetermined movement of said armature in a direction away from said winding.