Remote operated circuit breaker

Abstract

A circuit breaker having a movable contact arm for opening and closing the circuit which is controlled separately by a circuit breaker mechanism for circuit protection and by a switch lever mechanism which does not require actuation of the circuit breaker mechanism to function. The switch lever may be activated by a solenoid or other suitable means, and various interlocking mechanical states exist among the elements that provide added safety features.

Claims

1. A circuit breaker comprising: a first contact; a second contact moveable between a closed position and an open position relative to the first contact, where the second contact is electrically connected to the first contact only in the closed position; a unitary contact arm and lever assembly having a first end on which said second contact is mounted, a second end and a pivot point located between the first end and the second end; an actuator having a first position and a second position and directly acting on the second end of said unitary contact arm and lever assembly, said actuator moving said unitary contact arm and lever assembly solely about the pivot point when moved from the first to the second position putting said second contact in the open position; a handle having an on and an off position; said circuit breaker further including a circuit breaker linkage connecting said handle to said unitary contact arm and having a tripped state and an untripped state, said circuit breaker linkage changes the position of the second contact when the circuit breaker linkage changes state; a fault detector connected to said circuit breaker linkage, said fault detector causing said circuit breaker linkage to move from the untripped state to the tripped state in response to a sensed overcurrent; wherein said fault detector and said circuit breaker linkage remain in the untripped state and do not move when the actuator moves from the first position to the second position; wherein said actuator moves between the first position and the second position in response to a remote command signal; wherein the remote command signal is independent from the sensed overcurrent; and wherein said actuator comprises a solenoid with a plunger, wherein said plunger contacts said unitary contact arm.

2. The circuit breaker of claim 1, wherein when the circuit breaker linkage is in the tripped state, the second contact is in the open position.

3. The circuit breaker of claim 2, wherein when the circuit breaker linkage is in the tripped state, said actuator cannot move the second contact to the closed position.

4. The circuit breaker of claim 1, wherein the handle is disposed to move the contacts from the closed position to the open position in response to a manual operation.

5. The circuit breaker of claim 1, wherein the handle remains in the on position when the actuator moves from the first position to the second position.

6. The circuit breaker of claim 1, wherein the actuator comprises a permanent magnet disposed to bias the contacts.

7. The circuit breaker of claim 1, wherein the contacts are biased using a spring.

8. The circuit breaker of claim 1, wherein said circuit breaker linkage does not move when the actuator moves from the first position to the second position.

9. A circuit breaker comprising: a first contact; a second contact moveable between a closed position and an open position relative to the first contact, where the second contact is electrically connected to the first contact only in the closed position; a unitary contact arm and lever assembly having a first end on which said second contact is mounted, a second end and a pivot point located between the first end and the second end; an actuator comprising a permanent magnet disposed to bias the contacts, said actuator having a first position and a second position and directly acting on the second end of said unitary contact arm and lever assembly, said actuator moving said unitary contact arm and lever assembly about the pivot point when moved from the first to the second position putting said second contact in the open position; a handle having an on and an off position; said circuit breaker further including a circuit breaker linkage connecting said handle to said unitary contact arm and having a tripped state and an untripped state, said circuit breaker linkage changes the position of the second contact when the circuit breaker linkage changes state; a fault detector connected to said circuit breaker linkage, said fault detector causing said circuit breaker linkage to move from the untripped state to the tripped state in response to a sensed overcurrent; wherein when said actuator moves from the first position to the second position, said actuator moves only the unitary contact arm such that said circuit breaker linkage remains in the untripped state and does not move; and wherein said actuator comprises a solenoid with a plunger, wherein said plunger contacts said unitary contact arm.

10. The circuit breaker of claim 9, wherein said actuator moves between the first position and the second position in response to a remote command signal.

11. The circuit breaker of claim 10, wherein the remote command signal is independent from the sensed overcurrent.

12. The circuit breaker of claim 9, wherein when the circuit breaker linkage is in the tripped state, the second contact is in the open position.

13. The circuit breaker of claim 12, wherein when the circuit breaker linkage is in the tripped state, said actuator cannot move the second contact to the closed position.

14. The circuit breaker of claim 9, wherein the handle is disposed to move the contacts from the closed position to the open position in response to a manual operation.

15. The circuit breaker of claim 9, wherein the handle remains in the on position when the actuator moves from the first position to the second position.

16. The circuit breaker of claim 9, wherein the contacts are biased using a spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of an example circuit breaker according to aspects of the invention, showing a closed position.

(2) FIG. 2 is another side view of the example circuit breaker shown in FIG. 1, showing a remotely opened position.

(3) FIG. 3 is another side view of an example circuit breaker shown in FIGS. 1 and 2, showing a tripped position.

(4) FIG. 4 is a table reflecting various combinations of positions of the elements of the example circuit breaker shown in FIGS. 1-3 according to aspects of the invention.

(5) FIG. 5 is a state diagram reflecting various state transitions possible for the example circuit breaker shown in FIGS. 1-3 according to aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 illustrates an example circuit breaker 100 according to aspects of the invention.

(7) Circuit breaker 100 includes a stationary contact 105 connected to a line terminal 110. The line terminal receives electricity from a power source such as a generator (not shown), which in some applications is supplied by a power company.

(8) A movable contact 115 is disposed on a movable contact arm 120 which can be moved between a closed position 125 and open positions 200 and 300 (FIGS. 2 and 3) by pivoting on a first pivot 135 and second pivot 170.

(9) The movable contact arm 120 is connected to a tripping mechanism 140 by a linkage 145. As shown, tripping mechanism 140 is in an untripped state. The linkage may include a spring mechanism (not shown), which is biased to move the movable contact arm from the closed position to the open position when tripping mechanism 140 is tripped.

(10) A fault detector 150 is connected to the movable terminal and is configured to activate the tripping mechanism 140 when a fault condition occurs, such as excess current. In some applications, the fault detector is a solenoid which is disposed inline with the circuit. If the current through the solenoid exceeds a certain level, the solenoid generates an electromagnetic field sufficient to activate the tripping mechanism. The solenoid may also optionally incorporate a plunger or other armature which activates the tripping mechanism when the current exceeds a certain level.

(11) It is understood that other fault detection methods may also be employed, which trip the tripping mechanism upon the occurrence of a specific condition.

(12) Movable contact 115 is connected to load terminal 199 through fault detector 150 and connector 116. When movable contact 115 is in a closed position, as shown in FIG. 1, stationary contact 105 and moveable contact 115 are in contact with each other, and electricity can flow from line terminal 110 to load terminal 199 through contacts 105 and 115.

(13) A handle 160 is also provided for resetting the tripping mechanism 140, or for manually tripping the tripping mechanism 140.

(14) The moveable contact arm 120 includes a guide channel 165 which allows moveable contact arm 120 to slide and/or pivot around second pivot point 170. Moveable contact arm 120 also includes a lever 175. The lever may be formed in one piece with the movable contact arm 120, or may be a separate piece that is attached to the movable contact arm 120.

(15) Actuator solenoid 180 has a plunger 185 which is connected to lever 175. The lever 175, movable contact arm 120, and guide channel 165 are disposed such that when tripping mechanism 140 is in an untripped condition, as shown, and actuator solenoid 180 is activated, plunger 185 moves in the direction of arrow 190, moving movable contact arm 120 from closed position 125 to a second open position (200, FIG. 2) by pivoting movable contact arm 120 around pivot point 135 and sliding guide channel 165 along second pivot point 170.

(16) Incorporating an actuator such as actuator solenoid 180 to open and close contacts 105 and 115 in this way can have the advantage of allowing the number of manual operational cycles of the circuit breaker to be increased without incurring the additional costs associated with increasing the robustness of trip mechanism 140 and its associated components, as they are not actuated when the contacts are opened via the actuator solenoid. In this way, operational life can be increased to approximately 200,000 cycles in a typical application.

(17) Actuator solenoid 180 may be activated using a remote signal. Actuator solenoid 180 may be a bistable or latching solenoid, incorporating a permanent magnet 192. In this case, plunger 185 will hold its position unless actuator solenoid 180 is energized with the correct polarity.

(18) A polarity switch 194 may be connected to actuator solenoid 180 using connector 196. Polarity switch 194 can provide a pulse signal of either polarity to actuator solenoid 180 in order to extend or retract plunger 185. When no signal is present, plunger 185 is held in place by solenoid 180.

(19) Permanent magnet 192 may also be disposed such that when actuator solenoid 180 is de-energized, plunger 185 is drawn in the direction of arrow 190, opening the circuit by moving movable contact 115 from closed position 125 to second open position (200, FIG. 2).

(20) A biasing spring 198 may optionally be disposed to bias lever 175 such that plunger 185 only needs to provide force in one direction.

(21) FIG. 2 illustrates example circuit breaker 100 in a state where as in FIG. 1, the tripping mechanism 140 is untripped, but where movable contact arm 120 is in a second open position 200.

(22) FIG. 3 illustrates example circuit breaker 100 in a state where tripping mechanism 140 is tripped. Here, movable contact lever 120 has been moved by tripping mechanism 140 via linkage 145 such that movable contact 115 is held at open position 300. With tripping mechanism 140 in a tripped state, movable contact 115 cannot return to a closed state with stationary contact 105 regardless of the position of plunger 185. This means that it is impossible to re-engage the circuit breaker after a fault using a remote system via actuator solenoid 180.

(23) When the tripping mechanism 140 is in an untripped state as shown in FIGS. 1 and 2, contacts 115 and 105 may be freely opened and closed by actuating solenoid 180. However, when the tripping mechanism 140 is in a tripped state, contacts 115 and 105 cannot be brought back into a closed state by actuating solenoid 180. This can have the advantage of increasing safety by allowing an operator who is directly in the presence of circuit breaker 100 to override any attempts to re-close the breaker remotely or automatically which would result in a hazardous condition.

(24) Similarly, if power to polarity switch 194 is lost preventing actuation of actuation solenoid 180 while it is in the extended position, it remains possible to open contacts 115 and 105 using tripping mechanism 140 or handle 160, and to close contacts 115 and 105 using handle 160. However, if power to polarity switch 194 is lost preventing actuation of actuation solenoid 180 while it is in the retracted position, it is impossible to re-close the contacts using handle 160. This can have the advantage of increasing safety by preventing any attempts to re-close the breaker by operating handle 160 that would result in a hazardous condition. In some applications, an additional mechanism (not shown) may be incorporated to allow plunger 185 of actuation solenoid 180 to be moved to the extended position without requiring power to polarity switch 194.

(25) FIG. 4 is a table illustrating the various combinations of circuit breaker positions possible according to an example embodiment of the invention.

(26) When both the circuit breaker mechanism 140 and the lever 175 are in the on position (State A), the movable contact arm is in the closed position, and current can flow through the circuit breaker 100.

(27) From State A, if the circuit breaker mechanism 140 is toggled, e.g. by tripping the circuit breaker mechanism 140 manually or via an overcurrent condition, the moveable contact arm 120 moves to the first open position 300, and current can no longer flow through the circuit breaker 100.

(28) From State A, if the lever 175 is toggled, e.g. by remotely activating an actuation solenoid, the moveable contact arm 120 moves to the second open position, and current can no longer flow through the circuit breaker 100.

(29) When both the circuit breaker mechanism 140 and the lever 175 are in the off position (State B), the contact arm is in the first open position 300, and current cannot flow through the circuit breaker 100.

(30) From State B, if the circuit breaker mechanism 140 is toggled, e.g. by resetting the circuit breaker mechanism, the movable contact arm 120 moves to the second open position, and current still cannot flow through the circuit breaker 100. This can have the advantage of enabling a remote operator to prevent current flow even if a local operator were to reset the circuit breaker, for example, when a safety hazard is known to the remote operator.

(31) From State B, if the lever 175 is toggled, e.g. by remotely activating an actuation solenoid, the moveable contact arm 120 moves to the first open position 300, and current still cannot flow through the circuit breaker 100. This can have the advantage of enabling a local operator to prevent current flow even if a remote operator attempts to switch on the breaker, for example, when a safety hazard is known to the local operator.

(32) When the circuit breaker mechanism 140 is in the on position and the lever 175 is in the off position (State C), the movable contact arm is in the second open position, and current cannot flow through the circuit breaker.

(33) From State C, if the circuit breaker mechanism 140 is toggled, e.g. by tripping the circuit breaker mechanism 140 manually or via an overcurrent condition, the moveable contact arm 120 moves to the first open position 300, and current still cannot flow through the circuit breaker 100.

(34) From State C, if the lever 175 is toggled, e.g. by remotely activating an actuation solenoid, the movable contact arm moves to the closed position, and current can flow through the circuit breaker 100.

(35) When the circuit breaker mechanism 140 is in the off position and the lever 175 is in the on position (State D), the movable contact lever 175 is in the first open position 300, and current cannot flow through the circuit breaker 100.

(36) From State D, if the circuit breaker mechanism 140 is toggled, e.g. by resetting the circuit breaker mechanism, the movable contact lever 175 moves to the closed position, and current can flow through the circuit breaker 100.

(37) From State D, if the lever 175 is toggled, e.g. by remotely activating an actuation solenoid, the movable contact arm moves to the first open position 300, and current still cannot flow through the circuit breaker 100.

(38) FIG. 5 is a state diagram illustrating the different state transitions possible according to an example implementation of the invention, and as reflected in the table of FIG. 4. The only state which allows current to flow through the circuit breaker is State A. It is clear from the state diagram that it is impossible to transition directly from State B to State A without first passing through either State D or State C. Thus, State B can be thought of as a safety state of the circuit breaker 100.

(39) A transition to State A from State D is controlled by the circuit breaker mechanism 140, e.g., the local operator who can reset the mechanism. A remote operator can initiate a transition from State B to State A only by encountering State D, which is controlled by the local operator.

(40) Similarly, a transition to State A from State C is controlled by a lever operator, e.g., a remote operator actuating the lever 175 using solenoid 180. A local operator can initiate a transition from State B to State A only by encountering State C, which is controlled by the remote operator.

(41) In this way, the circuit breaker 100 can be configured to provide an added layer of safety by requiring logical agreement between the operators of the circuit breaker 100 before energizing a protected circuit.

(42) Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many modifications and variations will be ascertainable to those of skill in the art.