Circuit breaker assembly including a plurality of controllable circuit breakers for local and/or remote control

A circuit breaker assembly includes a plurality of controllable circuit breakers. Each of the controllable circuit breakers includes separable contacts, an operating mechanism structured to open and close the separable contacts, a trip mechanism cooperating with the operating mechanism to trip open the separable contacts, a first line terminal, a second load terminal, and at least a third terminal. The trip mechanism is structured to trip open the separable contacts responsive to a signal from the third terminal. The circuit breaker assembly also includes a toggle electrical switching apparatus that includes separable contacts electrically connected between the third terminal and ground, and a toggle operating member structured to open and close the separable contacts of the toggle electrical switching apparatus.

BACKGROUND

The disclosed concept pertains generally to electrical switching apparatus and, more particularly, to controllable apparatus, such as, for example, controllable circuit breakers. The disclosed concept further pertains to systems including electrical switching apparatus.

2. Background Information

Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. In small circuit breakers, commonly referred to as miniature circuit breakers, used for residential and tight commercial applications, such protection is typically provided by a thermal-magnetic trip device. This trip device includes a bimetal, which heats and bends in response to a persistent overcurrent condition. The bimetal, in turn, unlatches a spring powered operating mechanism, which opens the separable contacts of the circuit breaker to interrupt current flow in the protected power system.

Subminiature circuit breakers are used, for example, in aircraft or aerospace electrical systems where they not only provide overcurrent protection but also serve as switches for turning equipment on and off. As such, they are subjected to heavy use and, therefore, must be capable of performing reliably over many operating cycles. They also must be small to accommodate the high-density layout of circuit breaker panels, which make circuit breakers for numerous circuits accessible to a user. Aircraft electrical systems usually consist of hundreds of circuit breakers, each of which is used for a circuit protection function as well as a circuit disconnection function through a push-pull handle. The push-pull handle is moved from in-to-out in order to open the load circuit. This action may be either manual or, else, automatic in the event of an overload or fault condition. If the push-pull handle is moved from out-to-in, then the load circuit is re-energized. If the load circuit had been automatically de-energized, then the out-to-in operation of the push-pull handle corresponds to a circuit breaker reset action.

U.S. Pat. No. 7,570,146 discloses a panel mountable aircraft circuit breaker including a housing having an opening, separable contacts, an operating mechanism structured to open and close the contacts, and a trip mechanism structured to cooperate with the operating mechanism to trip open the operating mechanism. The trip mechanism includes a first bimetal to trip open the operating mechanism responsive to a thermal fault, a second ambient compensation bimetal to compensate the first bimetal, and an arc fault trip circuit to trip open the operating mechanism responsive to an arc fault.

U.S. Pat. No. 7,280,337 discloses a controllable circuit breaker comprising: a housing; a first input adapted to receive an external close signal; a second input adapted to receive an external open signal; a third input adapted to receive a control voltage; a set of main contacts; an operating mechanism for opening and closing the set of main contacts; a set of secondary contacts connected in series with the set of main contacts; a latching solenoid including a plunger latchable to a first position which closes the set of secondary contacts and to a second position which opens the set of secondary contacts, a first coil which when energized operates the plunger to the first position and a second coil which when energized operates the plunger to the second position, the first and second coils having a common node which is electrically connected to the third input; and a non-mechanical, electronic control circuit within the housing, the non-mechanical, electronic control circuit adapted to receive the external close and open signals from the first and second inputs and responsively energize the first and second coils, respectively, from the third input for a predetermined time. A non-mechanical, electronic circuit within the circuit breaker housing is adapted to provide a direct current status signal at an output when separable contacts are closed and a first or line terminal is energized with an alternating current voltage. The direct current status signal is representative of a second or load terminal being energized with the alternating current voltage.

There is room for improvement in circuit breaker assemblies.

SUMMARY

According to one aspect, a circuit breaker assembly includes a plurality of controllable circuit breakers. Each of the controllable circuit breakers includes separable contacts, an operating mechanism structured to open and close the separable contacts, a trip mechanism cooperating with the operating mechanism to trip open the separable contacts, a first line terminal, a second load terminal, and at least a third terminal. The trip mechanism is structured to trip open the separable contacts responsive to a signal from the third terminal. The circuit breaker assembly also includes a toggle electrical switching apparatus that includes separable contacts electrically connected between the third terminal and ground, and a toggle operating member structured to open and close the separable contacts of the toggle electrical switching apparatus.

According to another aspect, a circuit breaker assembly includes a backplane that includes an electrical bus structure, and a plurality of plug-in sockets. The circuit breaker assembly also includes a plurality of controllable circuit breakers. Each of the controllable circuit breakers includes separable contacts, an operating mechanism structured to open and close the separable contacts, a trip mechanism cooperating with the operating mechanism to trip open the separable contacts, a first plug-in member, a second plug-in member, and at least a third terminal. The first and second plug-in members plug into two of the plug-in sockets. The trip mechanism is structured to trip open the separable contacts responsive to a signal from the third terminal. The circuit breaker assembly also includes a toggle electrical switching apparatus that includes separable contacts electrically connected between the third terminal and ground, and a toggle operating member structured to open and close the separable contacts of the toggle electrical switching apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As employed herein, the term “number” shall mean one or an irate greater than one (i.e., a plurality).

As employed herein, the statement that two or more parts are “connected” or “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts. Further, as employed herein, the statement that two or more parts are “attached” shall mean that the parts are joined together directly.

The disclosed concept is described in association with remote control circuit breakers, although the disclosed concept is applicable to a wide range of controllable circuit breakers.

The disclosed concept employs a plurality of remote control circuit breakers (RCCBs) having a modular construction, thereby allowing electrical ganging or electrical linking of plural poles in order to control the RCCBs remotely and/or locally at the point of use. For example and without limitation, an on-board toggle switch or toggle circuit breaker is employed to electrically open and close the plural RCCBs at the point of use. The RCCBs can also be remotely controlled by electrical signals.

The disclosed concept provides: (1) a modular structure to address single-pole (FIGS. 1-5 and 8) and multi-pole applications (FIGS. 6 and 7); (2) electrical opening and closing responsive to near zero operator mechanism force (FIGS. 1-5 and 7) as contrasted with a conventional mechanical latch having significantly greater operator mechanism force; (3) on-site lockout/tag out maintenance of the RCCBs or system (FIGS. 1-5 and 7); and (4) a high power cut off switch and overload protection for direct faults including a contactor/relay with overcurrent protection, which can all be controlled at the RCCB (e.g., without limitation, a master on/off panel for a cargo handling system; a power panel in a marine vessel) without the use of fuses (FIGS. 1-5). The modular structure addresses single-pole and multi-pole applications by permitting one, two or more, various sources, and various voltages to be slaved together.

FIGS. 1-5show an assembly2that packages RCCBs4employing plug-in posts6,8(FIG. 5) to sockets10,12of an electrical bus structure, such as the example bus rail structure14. Alternatively, each pole of the three-pole RCCB16ofFIG. 7has two threaded posts18,20. The example assembly2can be employed, for example and without limitation, for high current packaging applications.

The example assembly2shown inFIG. 1includes six RCCBs4with three RCCBs4(shown inFIGS. 2 and 4) not being installed in order to show a feeder or line buss rail22and an output or load buss rail24of the bus rail structure14. Suitable electrical connections, such as the example sockets26(shown inFIGS. 2-5), electrically connect to a number of loads (not shown). A backplane28includes: (1) three independent feeds30,32,34for three-phases36,38,40, respectively, to an optional first plug-in tie-contactor C1(shown in phantom line drawing); (2) three independent feeds30′,32′,34′ for three-phases42,44,46, respectively, to an optional second plug-in tie-contactor C2(shown in phantom line drawing); and (3) direct electrical connection to three-phases48,50,52with or without a separate external contactor (not shown).

A ground bracket54provides mechanical retention of the RCCBs4and provides a common ground for internal RCCB electronics (not shown). The ground bracket54is electrically connected to a ground bus56by two fasteners58at each end. The ground bus56of the backplane28is electrically connected to a ground terminal59,59′ at each end. The ground bracket54is also electrically connected to two threaded mounting posts60of an RCCB mounting bracket62(FIG. 5) that pass through openings64(shown in hidden line drawing inFIG. 4) and are secured by nuts66. Each RCCB mounting bracket62is secured to the RCCB enclosure68by two fasteners70(FIG. 5), which provide a ground path for the RCCB electronics.

The RCCB4includes the two plug-in posts6,8(e.g., pins for load and line, respectively) for electrical connection to the corresponding sockets10,12of the backplane28. The RCCB4also includes a socket connector72(e.g., without limitation, eight sockets73shown inFIG. 6) for electrical connection to a corresponding pin header74of the backplane28. The example pin header74includes, for example, eight pins76for an indicator/control unit (ICU) signal, control power, an open/close signal, and auxiliary circuits. The backplane pin header74is electrically connected through a control printed circuit board78(FIG. 5) to a number of auxiliary and ICU output connectors80(FIG. 5), which communicate corresponding signals to or from a number of cockpit toggle circuit breaker(s), lights and other systems (not shown).

The feeder or line buss rail22holds the embedded sockets10for line connections to the nine RCCBs4(shown inFIGS. 2 and 4). Each set of three of the nine line sockets10is electrically connected to a corresponding one of three common phase A, B or C busses82,84,86. The example arrangement of the L-shaped, T-shaped and inverted L-shaped common phase busses88,90,92(FIG. 5) provides a suitable backplane size consolidation of the corresponding phase A, B and C busses82,84,86(FIG. 1). The output or load buss rail24holds the nine embedded load sockets10, each of which has a load buss bar94and a corresponding electrical connection, such as the example socket26, for electrically connecting a number of loads (not shown). For example, each of the sockets26can accept plural conductors (not shown) for multiple loads (e.g., single-phase loads; plural-phase loads, such as three-phase loads).

The disclosed concept allows the RCCBs4to be electrically connected in series as shown inFIG. 8, in order to increase the operating voltage (e.g., without limitation, 115 VAC to 230 VAC or 450 VAC by increasing the total arc gap). In this example, the plug-in backplane28is employed and the feeder or line buss rail22and the output or load buss rail24are suitably modified to provide serial electrical connections of two or more of the RCCBs4.

The example on-board toggle switch or toggle circuit breaker96is employed to electrically open and close the RCCBs4at the point of use. Alternatively, a remote toggle switch or toggle circuit breaker can be employed, as shown by the example remote toggle96′ (shown in phantom line drawing inFIG. 1). In the example configuration, one (#3) of the sockets73of the example socket header72(a portion of which is shown inFIG. 6) for each of the RCCBs4is for the ICU signal and is normally grounded by the normally closed separable contacts97(FIG. 6) of the normally closed toggle circuit breaker96. This causes the RCCBs to assume a closed state. Whenever one (or more) of the RCCBs4detects a thermal overload condition (e.g., without limitation, based upon a suitable I2t overload detection function) of one or more of the corresponding loads (not shown), such RCCB4trips and outputs a suitable current through the ICU signal to the toggle circuit breaker96. This current is selected to exceed the instantaneous trip threshold of the toggle circuit breaker96, which responsively trips open. Whenever the other non-tripped RCCBs4detect that the ICU signal is not grounded by the tripped open toggle circuit breaker96, those other non-tripped RCCBs4then responsively trip open.

Although a local or on-board toggle switch or toggle circuit breaker96is shown, a suitable toggle switch or toggle circuit breaker, such as the example remote toggle device96′, could be remotely located, for example and without limitation, in an aircraft or aerospace cockpit (not shown) and be a thermal circuit breaker with the toggle operating member101. This would allow remote opening and closing of a select RCCB4or an entire bus rail of RCCBs4. Similarly, if one of the RCCBs4trips from a thermal overload it can (if desired) send a suitable current to the remote toggle circuit breaker to indicate a fault (through the ICU signal). A toggle switch preferably can employ near zero operator mechanism force.

The example socket connector72for electrical connection to the backplane pin header74includes sockets73for three auxiliary contact signals (normally open (NO) S2, normally closed (NC) S3, and common S1for the NO and NC signals), the ICU signal (#3), 28 VDC or 115 VAC power (#5A), two internally connected sockets for 115 VAC power (#5A and #5B), optional back-up 28 VDC (#4) (e.g., without limitation, a second 28 VDC battery source (not shown) to the RCCB4in case a first 28 VDC main source (not shown) falls below a minimum operating level), and a signal (#6) (FIG. 6) that is normally ground and otherwise open for a trip. The ICU signal is connected to an open (when the separable contacts97of the circuit breaker96are open) to cause a trip of the RCCB4, and otherwise sources current when the RCCB4detects a trip condition. For example, for a thermal trip, a suitable magnitude of current is sourced from the ICU signal (#3), in order to cause the local toggle circuit breaker96to trip open and, thereby, cause tripping of all of the corresponding RCCBs4.

Alternatively, the RCCBs4can be electrically connected from the IWTS socket connector72of one of the RCCBs4to the IWTS socket connector72of another one of the RCCBs4as shown inFIG. 6in order to slave them together and form a multi-pole device. The ICU signal (#3) of one of the RCCBs4is normally grounded by the normally closed separable contacts97of the normally closed toggle circuit breaker96. The signal (#6) of that one of the RCCBs4is electrically connected to the ICU signal (#3) of the next one of the RCCBs4. Finally, the signal (#6) of that one of the RCCBs4is electrically connected to the ICU signal (#3) of the next one of the RCCBs4. This permits, for example and without limitation, three phases A,B,C of a three-phase load (not shown) to be controlled by three RCCBs4as a three-pole device.

As shown inFIGS. 1 and 3, the backplane28employs an integrated wire termination system (IWTS)98for the feeds30,32,34and the phases36,38,40, the feeds30′,32′,34′ and the phases42,44,46, and the phases48,50,52.

The local toggle circuit breaker96is on-board and is mounted to the backplane28(e.g., without limitation, a printed wiring assembly (PCA)) (FIGS. 1-5).

Alternatively, as shown inFIG. 7, a local toggle switch or toggle circuit breaker100is coupled to the side of a stand-alone stack of three example RCCBs102. Each of these RCCBs102includes mounting holes104and the two threaded posts18,20. The local toggle switch or toggle circuit breaker100includes a toggle operating member101structured to open and close the separable contacts (not shown, but see the separable contacts97ofFIG. 6) thereof, and preferably includes a lockout/tag out mechanism106(e.g., without limitation, a cross-bar which prevents the circuit breaker100from being opened by the toggle operating member101unless a separate action is taken to remove the cross-bar), which can be configured with various switches, guards or interlocks for servicing. Similar to the local or on-board toggle switch or toggle circuit breaker96ofFIGS. 1-5, the local toggle switch or toggle circuit breaker100opens and closes all the RCCBs102at the same time. Two key benefits include providing a relatively very low user force to open and close power banks, and providing the lockout/tag out mechanism106on the main electrical power panel RCCBs102at the point of use.

The adjacent local toggle switch or toggle circuit breaker100(or an electro-mechanical switchable circuit breaker) has the conventional lockout/tag out mechanism106and provides a common mechanism to open and close multiple RCCBs102with relatively very low operator force. The toggle circuit breaker100also allows the RCCBs102to be opened responsive to overcurrent from other systems (not shown).

InFIG. 7, a suitable barrier108is employed between each pair of adjacent poles and a suitable barrier110is employed between the two threaded posts18,20of each pole for electrical isolation from pole-to-pole and from line-to-load, respectively.

FIG. 8shows another assembly2′ of the RCCBs4ofFIG. 1in which two or more of these RCCBs are electrically connected in series. Otherwise, the assembly2′ can be similar to the assembly2ofFIG. 1in which the RCCBs4are not electrically connected in series. As is conventional, each of the RCCBs4includes separable contacts112, an operating mechanism114structured to open and close the separable contacts112, and a trip mechanism116cooperating with the operating mechanism114to trip open the separable contacts112.

The electrically opened and closed RCCBs4,102disclosed herein employ a near zero operator mechanism force with the on-board toggle switch or toggle circuit breaker96or the local toggle switch or toggle circuit breaker100that can be locked-out/tagged-out as contrasted with a conventional mechanical latch.

The modular structure of the disclosed concept addresses single-pole (FIGS. 1-5 and 8) and multi-pole applications (FIGS. 6 and 7) by permitting: (1) one line or source voltage, (2) two or more line or source voltages, (3) various source voltages or phases (FIGS. 1-5), and (4) various source voltages or phases to be slaved together (FIG. 6). For example and without limitation, for 28 VDC, there can be one toggle circuit breaker96per RCCB4. For three-phase 115 VAC, each of three phases can power three RCCBs4for three or more loads, and the nine RCCBs4can be controlled by one toggle circuit breaker96(FIGS. 1-5). For three-phase 115 VAC, each of three phases can power three RCCBs4for three or more loads, and the three RCCBs4per phase can be controlled by three toggle circuit breakers (not shown, but similar to the one toggle circuit breaker96), one for each phase. For example and without limitation, phase A powers motors, phase B powers pumps, and phase C powers fans.

The example assembly2including the RCCBs4employs plug-in posts6,8to the feeder or line buss rail22and the output or load buss rail24for high current applications.

Each of the example RCCBs4,102includes two plug-in posts6,8(FIGS. 1-5 and 8) or two threaded posts18,20(FIG. 7). For example and without limitation, the RCCBs4,102are rated up to 200 A.