Patent Application
20230197389
The present disclosure relates to an electrical switching apparatus and, more particularly, but not exclusively, relates to circuit breakers, including a reset lockout mechanism engaged by a single actuator, such as a rocker.
The electrical wiring device industry has witnessed an increasing call for circuit interrupting devices or systems which are designed to protect from dangers presented by overcurrent (e.g., overload/short circuits), ground faults, and arc faults. In particular, electrical codes require electrical circuits in home bathrooms and kitchens to be equipped with ground fault circuit protection. For instance, GFCI devices are resettable after they are tripped by, for example, the detection of a ground fault. A test button can be used to test the circuitry and trip mechanism used to sense faults. A reset button can be used to reset the electrical connection between input and output conductive paths. Certain resettable circuit interrupting devices are capable of locking out the reset portion of the device if the circuit interrupting portion is non-operational or if an open neutral condition exists.
Existing resettable circuit breakers that offer fault protection capabilities have line phase and neutral terminals as well as load phase and neutral terminals. Additionally, resettable circuit breakers also have a switch for controlling power distribution to the load phase terminal. To provide fault protection, such circuit breakers have sensing circuitry, which is capable of sensing faults (e.g., ground faults). The circuitry may be coupled to an actuator (e.g. an electromechanical actuator or a solenoid) such that upon sensing a fault, the circuit may cause the actuator to open the switch.
Existing challenges associated with the foregoing, as well as other challenges, are overcome by systems and methods which operate in accordance with the present disclosure.
According to one aspect, this disclosure is directed to a circuit breaker. The circuit breaker includes a conductive path, a linkage, a reset lockout mechanism, a line phase terminal, a load phase terminal, and a line neutral terminal. The conductive path is formed between the line and load phase terminals. The conductive path has an open configuration and closed configuration. The linkage is configured to move the conductive path between the open configuration and the closed configuration. The reset lockout mechanism configured to prevent the conductive path from moving to the closed configuration when a predefined condition exists. The reset lockout mechanism includes a rocker and an armature. The rocker is selectively engageable with the linkage, the rocker configured to move the linkage between an open position and a closed position. The armature is selectively engageable with the rocker to maintain the conductive path in the open configuration when the predefined condition exists.
In embodiments, the predefined condition may include a ground fault between the load phase terminal and the line neutral terminal.
In various embodiments, the reset lockout mechanism may further include a solenoid including a plunger, the solenoid configured to move the plunger between a first position and a second position, the plunger operatively coupled to the armature.
In some embodiments, the rocker may include an engagement face configured to engage the armature.
In certain embodiments, the armature may include a first arm including an outer surface defining a pocket configured to contact the engagement face of the rocker to provide a mechanical stop and prevent the rocker from turning to a position that corresponds to an ON state of the circuit breaker.
In embodiments, the armature may further include a second arm that defines an armature slot. The plunger may include a lip configured to engage the armature slot.
In various embodiments, the reset lockout mechanism may further include a spring configured to serve as a detent and keep the armature in position.
In some embodiments, the engagement face may be configured to strike the armature as the rocker returns to a position corresponding to an OFF state of the circuit breaker.
In certain embodiments, the rocker may be movable between the first position in which the conductive path is in the open configuration corresponding to the OFF state of the circuit breaker, a mid-trip position in which a fault or overcurrent condition is present, and a second position in which the conductive path is in the closed configuration corresponding to the ON state of the circuit breaker.
In embodiments, when the rocker is in the mid-trip position, a mating of the engagement face of the rocker with the pocket of the armature may prevent the rocker from moving directly to the second position corresponding to an ON state of the circuit breaker.
In various embodiments, a first end of the linkage may be operably coupled to a bottom extension of the rocker and associated with the line phase terminal such that movement of the linkage is configured to selectively move the conductive path between the open and closed configurations. The linkage may have a second end movably received within a linkage slot defined by a catch and a contact arm.
According to another aspect, this disclosure is directed to a reset lockout mechanism for a circuit breaker. The reset lockout mechanism includes a linkage, a rocker, an armature, a solenoid, and a plunger. The linkage is positioned to move between an open position and a closed position. The rocker is selectively engageable with the linkage. The armature is selectively engageable with the rocker. The plunger is supported by the solenoid and operatively coupled to the armature, the plunger movable between a first position and a second position.
In embodiments, a conductive path may be formed between line and load phase terminals, the conductive path having an open configuration and a closed configuration. The reset lockout mechanism may be configured to prevent the conductive path from moving to the closed configuration when a predefined condition exists.
In various embodiments, the predefined condition may include a ground fault between the load phase terminal and the line neutral terminal.
In some embodiments, the solenoid may be configured to move the plunger between the first position and the second position.
In certain embodiments, the rocker may include an engagement face configured to engage the armature.
In embodiments, the armature may include a first arm including an outer surface defining a pocket configured to contact the engagement face of the rocker to provide a mechanical stop and prevent the rocker from turning to a position that corresponds to an ON state of the circuit breaker.
In various embodiments, the armature may further include a second arm that defines an armature slot. The plunger may include a lip configured to engage with the armature slot.
In some embodiments, the reset lockout mechanism may further include a spring configured to serve as a detent and keep the armature in position.
According to still another aspect, this disclosure is directed to a method for preventing closing of a conductive path in a circuit breaker if a predefined condition exists. The method includes: determining if a fault condition is detected when a rocker is moved from a first position corresponding to an OFF state of the circuit breaker to a second position corresponding to an ON state of the circuit breaker, wherein the circuit breaker includes a line phase terminal and a load phase terminal, and wherein the circuit breaker further includes a conductive path formed between the line and load phase terminals. In a case where the fault condition exists, the method further includes: de-energizing a solenoid including a plunger, the solenoid configured to move the plunger to a first position when the solenoid is de-energized; moving, by the plunger, an armature to a first position, the armature configured to lock the rocker in the first position in which the conductive path is open corresponding to the OFF state of the circuit breaker; and preventing closing of the conductive path based on the first position of the armature. In a case where the fault condition does not exist, the method further includes: energizing the solenoid including a plunger, the solenoid configured to move the plunger to a second position when the solenoid is energized; moving, by the plunger, the armature to the second position, unlocking the rocker from the armature; and closing of the conductive path based on the second position of the armature in which the conductive path is closed corresponding to the ON state of the circuit breaker.
According to still another aspect, this disclosure is directed to a circuit breaker. The circuit breaker includes a line phase terminal, a load phase terminal, a line neutral terminal, a conductive path formed between the line and load phase terminals, the conductive path having an open configuration and closed configuration, a linkage configured to move the conductive path between the open configuration and the closed configuration, a rocker selectively engageable with the linkage, the rocker configured to move the linkage between an open position and a closed position, and an armature selectively engageable with the rocker to prevent the conductive path from being in the closed configuration when the predefined condition exists.
In various embodiments, the predefined condition may include a ground fault between the load phase terminal and the line neutral terminal.
In certain embodiments, the circuit breaker may further include a solenoid that supports a plunger, the solenoid configured to move the plunger between a first position and a second position. The plunger includes a distal portion and a proximal portion. The proximal portion may be configured to provide a mechanical stop. The distal portion of the plunger may be operatively coupled to the armature.
In some embodiments, the rocker may include an engagement face configured to engage the armature.
In various embodiments, the armature may include a first arm including an outer surface defining a pocket configured to contact the engagement face of the rocker to provide a mechanical stop and prevent the rocker from turning to a position that corresponds to an ON state of the circuit breaker.
In certain embodiments, the armature may further include a second arm that defines an armature slot and the plunger includes a lip configured to engage the armature slot.
In some embodiments, the circuit breaker may further include a spring configured to serve as a detent and keep the armature in position.
In various embodiments, the engagement face may be configured to strike the armature as the rocker returns to a position corresponding to an OFF state of the circuit breaker.
In certain embodiments, the rocker may be movable between the first position in which the conductive path is in the open configuration corresponding to the OFF state of the circuit breaker, a mid-trip position in which a fault or overcurrent condition is present, and a second position in which the conductive path is in the closed configuration corresponding to the ON state of the circuit breaker.
In some embodiments, when the rocker is in the mid-trip position, a mating of the engagement face of the rocker with the pocket of the armature may prevent the rocker from moving directly to the second position corresponding to the ON state of the circuit breaker.
In various embodiments, a first end of the linkage may be operably coupled to a bottom extension of the rocker and associated with the line phase terminal such that movement of the linkage is configured to selectively move the conductive path between the open and closed configurations, the linkage having a second end moveably received within a linkage slot defined by a catch and a contact arm.
The details of one or more aspects of this disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description, the drawings, and the claims that follow.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of this disclosure and, together with a general description of this disclosure given above, and the detailed description of the embodiment(s) given below, serve to explain the principles of this disclosure, wherein:
The figures depict embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the present disclosure described herein.
The present disclosure relates to resettable circuit interrupting devices or circuit breakers for opening and closing electrical communication between line terminals (e.g., input) and load terminals (e.g., output) of a device. Electrical communication between the line and load terminals may be enabled by establishing a conductive path between the line and load terminals. The devices described herein may be of any suitable type such as, without limitation, ground fault circuit interrupters (GFCIs), arc fault circuit interrupters (AFCIs), ground fault protection equipment (GFPE), and suitable combinations thereof (e.g. AFCI/GFCI breakers). Generally, circuit interrupting devices according to the present disclosure include a circuit interrupter, a reset portion, a reset lockout mechanism, and a trip portion. It is contemplated that the circuit interrupter, reset portion, reset lockout mechanism and trip portion may be combined or otherwise implemented in a variety of ways without departing from the spirit or scope of the present disclosure.
The circuit breaker includes line side phase and neutral terminals as well as load side phase and neutral terminals. The line side phase terminal is capable of transmitting electrical power to the load side phase terminal when the line side phase terminal is in electrical communication with the load side phase terminal. Similarly, the line side neutral terminal is capable of transmitting electrical power to the load side neutral terminal when the line side neutral terminal is in electrical communication with the load side neutral terminal. The line side phase and neutral terminals connect to a power source, and the load side phase and neutral terminals connect to a branch circuit having one or more loads. These terminals may be, for example, any suitable electrical fastening devices, such as, but not limited to binding screws, lugs, binding plates, jaw contacts, pins, prongs, sockets, and/or wire leads, which secure conductive paths to the circuit breaker, as well as conduct electricity.
The circuit interrupting and reset portions generally use electromechanical component(s) to break and reestablish the conductive path between line and load phase terminals, and between line and load neutral terminals, respectively. Examples of such electromechanical components include solenoids, bimetallic components, hydraulic components, switches, relays, contactors, or any other suitable components capable of being electromechanically engaged so as to break or reestablish conductive paths between the line and load terminals. In some embodiments, circuit interrupters are separated in response to specific fault types, such as the presence of an overcurrent, a ground fault, an arc fault, or a combination thereof. Additionally, the same circuit interrupter may be used to protect against overcurrent, ground fault, arc fault conditions, or combinations thereof. Additionally, there may be individual circuit interrupters configured to react to overcurrent, ground fault, or arc fault protection, with the individual circuit interrupters configured to share certain components.
To protect against overcurrent, arc faults, and ground faults, the circuit interrupter breaks the electrical continuity between the line and load phase terminals by opening the circuit when a fault is detected. For example, at least one mechanical connection between components associated with the conductive paths may be removed.
Once the circuit interrupter breaks the conductive path, the reset lockout mechanism is configured to prevent the circuit breaker from resetting or reestablishing a continuous or closed conductive path while a predefined condition or fault exists. The reset lockout mechanism may be any lockout mechanism capable of preventing the reestablishment of the conductive path. For example, such mechanism can include mechanical and/or electrical components and/or a predefined routine performed by a control circuit that functions to prevent the conductive path from reestablishing. For instance, one or more of the mechanical components of the circuit breaker can transition to a position in which the circuit breaker is in an OFF state where such components are positioned to lock out one or more components of the circuit breaker to prevent the conductive path from being reestablished.
Various types of circuit interrupting devices are contemplated by the present disclosure. Generally, circuit breakers are used as resettable branch circuit protection devices that are capable of opening conductive paths supplying electrical power between line and load terminals in a power distribution system (or sub-system). The conductive paths transition from a CLOSED configuration (e.g., ON) to an OPEN configuration (e.g., OFF), for example, if a fault is detected or if the current rating of the circuit breaker is exceeded. Detection of faults may be performed by mechanical components and/or electrical components. Once a detected fault is cleared, the circuit breaker may be reset to enable reestablishment of the conductive path.
The circuit breakers can provide fault protection for various types of faults or a combination of such faults. Faults can include conditions that render the circuit unsafe due to the presence of an abnormal electric current and/or voltage. Examples of faults contemplated include, without limitation, ground faults, arc faults, immersion detection faults, appliance leakage faults, and equipment leakage faults. Although various types of fault protection circuit breakers are contemplated, for purposes of clarity, the following descriptions will be made with reference to GFCI circuit breakers and AFCI circuit breakers.
An exemplary embodiment of a GFCI circuit breaker incorporating a reset lockout mechanism will now be described. Generally, each GFCI circuit breaker has a circuit interrupter, a reset portion, a reset lockout mechanism for selectively locking the circuit breaker in either an OFF or MID-TRIP state. Each GFCI circuit breaker may further include a trip portion which operates independently of the circuit interrupter. The trip portion may selectively transition the circuit breaker into a MID-TRIP state.
In the GFCI circuit breaker, the circuit interrupting and reset portions may include electromechanical components configured to selectively open or break and/or close or reestablish conductive paths between the line and load phase terminals. Additionally, or alternatively, components such as solid-state switches or supporting circuitry may be used to break or reestablish the conductive path. The circuit interrupter automatically breaks electrical continuity along the conductive path (e.g., opens the conductive path) between the line and load phase terminals upon detection of a ground fault, overcurrent, or arc fault, or any combination thereof. The reset portion enables reestablishing electrical continuity along the conductive path between the line phase terminal and the load phase terminal. The reset portion also enables reestablishing electrical continuity along the conductive path between the line neutral terminal and the load neutral terminal. In embodiments, the reset portion may cause the reset lockout mechanism to transition to a MID-TRIP position that corresponds to the MID-TRIP state of the circuit breaker. Operation of the reset portion and reset lockout mechanism may occur in conjunction with operation of the circuit interrupter so that the conductive path between the line and load phase terminals cannot be reestablished if the circuit interrupter is non-operational or if a fault is detected.
Particular embodiments of the present disclosure are described herein with reference to the accompanying drawings. However, it is to be understood that the disclosed embodiments are merely exemplary embodiments of the present disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail so as to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to particular embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the present disclosure as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the spirit and scope of the present disclosure.
With reference to
The reset lockout mechanism 10 generally includes a rocker 300, an armature 400, a solenoid 197, a plunger 208, a detent spring 204, and a linkage 206. The rocker 300 of the reset lockout mechanism 10 is disposed partially within the housing 101 of the circuit breaker 100 and is positioned to transition between an OFF position (see
The rocker 300 partially extends outward through housing 101 of the circuit breaker 100 and is configured for user access for manually operating the circuit breaker 100. The rocker 300 is pivotably coupled to the housing 101 about a pivot pin 311.
With reference to
The body 306 of the rocker 300 includes a strike arm 308, a lock nub 304, and a bottom extension 307 defining a hole 307a. The strike arm 308 is configured to mechanically engage the armature 400 during a fault condition. The outer surface of the strike arm 308 includes a first barrel 308b, a second barrel 308c, a top face 308d, an armature engagement face 308a, and a side face 308e. The armature engagement face 308a is configured to mechanically engage the armature 400 during a fault condition.
The lock nub 304 is configured to mechanically engage the armature 400 to prevent the rocker 300 from moving in a direction “A” before it is determined that the breaker is operational. The outer surface of the lock nub 304 includes an outer surface having a curved engagement face 304a, although the engagement face 304a may have any suitable geometric configuration.
The finger 309 is operatively coupled to switch spring 211 (
When the circuit breaker 100 is in the OFF state (
The solenoid 197 is configured to be energized by the controller “C.” When energized, the solenoid 197 generates a magnetic field sufficient to move the plunger 208 from a first position (see
With continued reference to
The second contact 192 is adjacent to, and in electrical communication with, the line terminal “LINE-T.” When the first contact 190 and the second contact 192 are mechanically coupled, electrical power may be conducted therebetween. When the rocker 300 is in the OFF position (which corresponds to the OFF state of the circuit breaker 100), the first and second contacts 190, 192 are not mechanically coupled and are not in electrical communication.
The circuit breaker 100 further includes a catch 150 configured to mechanically engage with the linkage 206 and the contact arm 180. The catch 150 includes a proximal portion 151, a distal portion 153, and a plate 152. The distal portion 153 includes a first linkage portion 155 and a catch portion 157. Catch portion 157 may include a curved portion that protrudes outwardly from a surface of catch 150. Catch 150 is biased in a first position by a spring 158.
To clear the reset lockout mechanism 10 before returning the circuit breaker 100 to the ON state thereof, and/or to verify that the circuit interrupter is operational (e.g., that the circuit is capable of sensing a fault, that solenoid 197 is functioning, and/or that the armature 400 is functioning), electrical power needs to be available to a control circuit or controller “C” of the circuit breaker 100. This is achieved by supplying power to the controller “C” from the line terminal “LINE-T.” Power is supplied from the line side, to a DC power supply circuit, and then to the controller “C.”
Additional circuit protection components may be included as well, including, without limitation, metal oxide varistors (MOVs) and fuses. By powering the controller “C” with power supplied by the line terminal “LINE-T,” the circuit interrupter, including the solenoid 197 and components associated with the solenoid 197, may be tested (since power is available via a controller power supply) prior to resetting the circuit breaker 100 (e.g., prior to disengaging the reset lockout mechanism 10 to allow the circuit breaker 100 to return to the ON state). As a result, the load terminal “LOAD-T,” as well as components of the circuit breaker 100 coupled to a load side contact 250, do not receive electrical power during testing of the circuit interrupter.
In various embodiments, the circuitry of circuit breaker 100 may include a GFCI integrated circuit (IC) (not shown) and a controller “C.” The GFCI IC is used to detect ground faults and G/N faults and is electrically coupled to a differential transformer (not shown) and a G/N transformer (not shown). The microprocessor or controller “C” can perform additional functionality, such as event logging and self-testing. Event logging may include recording a history of tripping (transitioning to the OFF state), resetting (transitioning to the MID-TRIP state), manual OFF, component failure, and any other suitable event. Self-testing by the controller “C” enables the automatic or selective testing of the components of the circuit breaker 100 without the need for user intervention. In embodiments, the controller “C” may temporarily disable firing the solenoid 197 during the self-test by applying a signal at the output of the controller “C.”
Additionally, the controller “C” may energize the solenoid 197 to cause the circuit breaker 100 to transition from the MID-TRIP state to the ON state thereof. To energize the solenoid 197 when transitioning the circuit breaker 100 from the TRIP or MID-TRIP state to the ON state thereof, the controller “C” transmits a signal to the silicon controlled rectifier (SCR) (not shown). Subsequently, the solenoid 197 is energized, thereby displacing the plunger 208 to the left (in relation to the figures). For a further description of the SCR, reference may be made to U.S. application Ser. No. 16/322,039, filed on Jan. 30, 2019, the disclosure of which is hereby incorporated by reference in its entirety.
State, position and/or condition information is electronically communicated to the controller “C.” The controller “C” uses this information for event logging (e.g., of tripping and/or resetting of circuit breaker 100). The controller “C” can also monitor other portions of the circuitry to detect whether various portions of the circuitry (e.g., mechanical and/or electric component failures) have failed, are failing, or will fail within some predetermined predictive failure parameter (e.g., time, use, etc.). In addition, the controller “C” is electrically coupled to an indicator (e.g., an LED light assembly; see
With reference to
With reference to
With reference to
Initially, in
With reference to
As the rocker 300 is rotated towards the ON position thereof (see
The first end 206b of the linkage 206 is coupled to and mechanically engaged by the bottom extension 307 of the rocker 300. The catch 150 is pivotably coupled to the housing 101 and mechanically cooperates with contact arm 180. The contact arm 180 is pivotably connected to the housing 101 at the same point as the catch 150. The contact arm 180 and the catch 150 are configured to mechanically cooperate to enable the first and second contacts 190, 192 of the contact arm 180 to make electrical contact during the ON condition of the circuit breaker 100. The contact arm 180 and the catch 150 define a slot 184 in a first position of the contact arm 180 and a first position of the catch 150. The second end 206a of the linkage 206 slidably engages the slot 184 and rotates the contact arm 180 and the catch 150 clockwise.
With continued reference to
With reference to
With reference to
As the rocker 300 continues to be rotated towards the OFF position thereof, the armature engagement face 308a of the rocker 300 mechanically engages the armature 400. The armature 400 is rotated into the first position thereof. The proximal portion 209 of the plunger 208 pushes against the plate 152 of the catch 150 and functions as a stop.
Referring now to
If the measurements of current between the line terminals “LINE-T” and the load terminals “LOAD-T” indicate a current imbalance or vary beyond a predetermined threshold, the controller “C” may determine that a ground fault or G/N fault condition is present. Additionally, the controller “C” may receive sensor signals indicative of an arc fault. For example, a high-frequency transformer and/or other components/circuitry of transformer assembly may provide sensor signals indicative of an arc fault.
Upon determining that any of the faults described throughout this disclosure are present (Step 754), the controller “C” further determines the state (e.g., ON or OFF) of the circuit breaker 100 (Step 758). In a case where the controller “C” determines that a fault is present and circuit breaker 100 is in the OFF state (Step 758), the circuit interrupting portion is or becomes engaged (Step 762). Alternatively, if no fault is detected, and the controller “C” determines that the circuit breaker 100 is in the ON state (Step 756), the controller “C” may further determine whether a predetermined condition exists requiring the circuit breaker 100 to transition to the OFF state. Once a fault (or predetermined condition) is detected, the circuit breaker 100 may display an indication to users indicative of the presence or type of fault (see
If a fault (or predetermined condition) is detected (Step 754) and the circuit breaker 100 is determined not to be in the OFF state, the controller “C” sends a control signal to energize the circuit interrupter, which may be a solenoid 197 (Step 762). Once the solenoid 197 receives the control signal from the controller “C,” the solenoid 197 generates a magnetic field, thereby drawing the plunger 208 from the first position to the second position. Drawing the plunger 208 to the second position transitions the circuit breaker 100 from the ON state thereof to the OFF state thereof. As a result, when a user attempts to transition the circuit breaker 100 to the ON state, the controller “C” must, once a fault is no longer detected (Step 754), reenergize the solenoid 197 to transition the circuit breaker 100 to the ON state.
If no fault (or predetermined condition) is detected (Step 754), the controller “C” determines the state of the circuit breaker 100 (e.g., OFF or ON state) (Step 756). If the controller “C” determines the circuit breaker is in the OFF state, the controller “C” sends a control signal to the solenoid to draw the plunger 208 into the first position to transition the circuit breaker 100 to the MID-TRIP state (760). Once the circuit breaker 100 is in the MID-TRIP state, force applied to the first side 303 transitions the circuit breaker 100 to the OFF state. When force is applied to the second side 105 of the rocker 300 in the direction “A” (
With reference to
More specifically,
In addition to the mechanical indication provided by the rocker 510, the one or more indicators 503 may be included. For example, a GFCI circuit breaker may have a first indicator 503a, which may be in the form a first LED, disposed in a first location, an AFCI circuit breaker may have a second indicator 503b, which may be in the form a second LED in a second location, and a combination AFCI/GFCI circuit breaker may include the first and second indicators 503a, 503b (e.g., LED) in both the first and second locations, respectively. By locating the indicators 503 in the first location, the second location, or both the first and second locations based on the type of protection provided by the circuit breaker (GFCI, AFCI, and AFCI/GFCI respectively), a more intuitive user interface 500 is provided. This user interface 500 may help users distinguish between different circuits when viewing multiple circuit breakers disposed along a circuit breaker panel (not shown) since the indicators will be aligned.
In the case of a GFCI circuit breaker, the various states may be indicated as in the following table.
In the case of an AFCI circuit breaker, the various states may be indicated as in the following table.
In the case of an AFCI/GFCI circuit breaker, the various states may be indicated as in the following table.
It is contemplated that the various states indicated by signals produced by the window 502 and/or the GFCI and AFCI indicators 503 may vary depending on the types of faults which the circuit breaker is capable of identifying, a display hierarchy for identifying particular faults, etc.
Circuit breakers may employ trip mechanisms, which include, without limitation, solenoids, bimetallic components, and/or hydraulic components. In the case of a trip mechanism which includes bimetallic components, the speed at which it trips is directly proportional to the amount of overcurrent passing therethrough due to the heat generated by the overcurrent. This is commonly referred to as a trip-time curve of a circuit breaker. Regulatory authorities such as Underwriters Laboratories (UL) define limits on the amount of time a circuit breaker may take to trip at a given current level. However, the trip-time curve may vary among circuit breakers depending on the application and requirements associated with a particular installation. Such variation in the trip-time curve is acceptable as long as it does not exceed the defined limit prescribed by applicable regulatory authorities.
Other trip mechanisms, such as solenoids, may trip near instantaneously once a given current threshold is reached. With such mechanisms, it may be beneficial to introduce a delay in tripping based on current level to replicate a trip-time curve.
In certain embodiments, circuit breakers may include mechanisms to introduce a delay in tripping based on a detected current level to replicate a trip-time curve. These embodiments are similar to the other embodiments describe above except that they include an additional current sensor to measure the current flowing through the branch circuit (not shown). The controller of the circuit breaker monitors the current level detected by the current sensor, and when the controller detects a fault or overcurrent, the controller may set a delay time before which it will trip the circuit breaker based on the current level sensed by the current sensor. The trip-time curve may be modified by the controller based on the desired circuit breaker operation. For example, the circuit breaker can be programmed with one or more of a plurality of trip-time curves to fit any given application. In addition, the trip-time curve could be customized or modified for a particular user based on the user's requirements while still meeting the defined limit prescribed by applicable regulatory authorities.
With reference to
With reference to
Persons skilled in the art will understand that the structures and methods specifically described herein and shown in the accompanying figures are non-limiting exemplary embodiments, and that the description, disclosure, and figures should be construed merely as exemplary of particular embodiments. This disclosure is not limited to the precise embodiments described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, the elements and features shown or described in connection with certain embodiments may be combined with the elements and features of certain other embodiments without departing from the scope of this disclosure, and that such modifications and variations are also included within the scope of this disclosure. Accordingly, the subject matter of this disclosure is not limited by what has been particularly shown and described.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16707535 | Dec 2019 | US |
| Child | 18112873 | US |
