Abstract:
A replaceable circuit breaker module has a housing for supporting and enclosing elements of the module, a circuit breaker mounted in the housing in a manner that an action of installing the module connects the breaker to bridge an incoming and an outgoing conductor, and monitoring circuitry for monitoring characteristics of the circuit breaker, the monitoring circuitry mounted in the housing and having a first connector element for engaging a mating connector element in the action of installing the module. The module is characterized in that action of withdrawing the circuit breaker module also withdraws the monitoring circuitry. Sensors in the monitoring circuitry may include sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is in the area of electric power distribution, and has particular application to power distribution for rack-mounted electronic systems.  
         BACKGROUND OF THE INVENTION  
         [0002]    Power distribution systems in current art exist for routing and/or converting AC or DC power to devices or systems in a wide variety of situations, and have been the subject of considerable research and development. A variety of power distribution systems have been developed to power systems and devices in many different applications that vary greatly in voltage, wattage, design and sophistication, depending on the power requirements and other specific requirements of the application. For example, in some applications the systems or devices powered by the distribution system are allowed to completely power down during repair or upgrade of the power distribution system itself, or any component of the system, while other applications may require that the powered systems or devices remain at least partially powered on and functioning during such events.  
           [0003]    In critical applications such as systems for routing or switching data packets on the Internet, the computer equipment and devices require constant and consistent power to be supplied at all times to allow for continuous and extended operation under all power conditions, maintaining a high degree of operating reliability for data or process security.  
           [0004]    Uninterruptible and redundant power distribution systems have been incorporated to achieve this “always-on” feature. Such systems, through such as parallel connection and operation, allow for repair or replacement of some part of the power system without disrupting the power distributed. It is in this critical environment that embodiments of the present invention are used.  
           [0005]    Such power distribution systems are used with Internet routing equipment of various size and capacity, ranging from small desktop pedestal units, to mid and upper-range routing systems. Components of the power distribution system are sometimes contained within the chassis of the router, often accessible from the back of the chassis, as in the case of a pedestal unit. However, with current and probable future growth of network traffic over the Internet, it is desirable for many Internet routing equipment users to be capable of long-term traffic-handling capacity growth and extremely high availability of the routing equipment, expandable (scalable) in accordance with demand.  
           [0006]    In order for Internet routing service providers to respond to growing traffic-handling needs and to achieve gigabit and terabit-per-second data-handling performance, multi-chassis, scalable router designs are being incorporated, allowing installation of additional modular components. The scalable chassis, commonly referred to as a rack chassis in the art, also incorporates a scalable circuit breaker and power distribution system in order to adequately serve the additional power requirements of added (scaled-up) circuitry. A scalable circuit breaker system typically comprises a plurality of removable breaker boxes modularly mounted in separate slots or assemblies within the rack chassis, which is often the same chassis containing the modular units comprising the cards and other components of the router. The combination of breaker boxes has the primary function of protecting the router components in the case of a power surge or overload, and during such an event, continues to distribute uninterrupted power to conductors distributing power elsewhere in the router.  
           [0007]    In such a system separate breaker modules are connected in parallel to points on the incoming and outgoing power carrier so that one of a pair of breaker modules in a live power distribution system can be removed for repair or upgrade, for example, while the remaining connected module continues to supply constant and interrupted power to the components of the router. Hot-swapping, as it is known in the art, is a frequently practiced method of module removal and insertion in many different systems were constant power delivery is critical.  
           [0008]    The components of a large, scalable Internet router as described herein typically operate at DC voltage that is commonly supplied to the breaker modules of the scalable router by a battery room which converts the primary power of the host facility to DC power. The converted DC power is supplied to the breaker modules at low voltage and high amperage level depending on the power requirements. The rack-mounted breaker modules utilize standard breaker switches for circuit protection, and additional safeguards are often incorporated in such power systems to maintain reliability and availability of the power, as well as to minimize electrical hazards.  
           [0009]    In an extremely critical environment such as for Internet data routing as described above, system up time must be maximized, and any malfunction or anomaly within the routing equipment or power distribution system must be quickly identified and rectified. For a technician or worker remotely monitoring the operation of the circuit breaker system for large scalable Internet router, for example, it is particularly important for all of the monitored data of circuit breaker operating status to be complete and accurate. One problem inherent with large and complex systems with remote monitoring or control capability such as described above, is that, should a failure or malfunction occur in the monitoring card or any of the connections between it and the circuit breakers, the reliability of the data send for monitoring is compromised, and a false indication may be given. Additionally, determination of the cause of a problem indicated by the monitor, such as low voltage in a circuit breaker, for example, may not actually be true, but instead a malfunction within the monitoring card causing a false reading. In such a circuit breaker monitoring system with centralized intelligence on a monitoring card, such as is common in current art, it can be difficult for a worker or technician to accurately determine if the reported problem is real and has a real cause, or is misrepresented by a faulty monitoring card. Such a monitoring system decreases in reliability and dependability as the size and complexity of the system increases. As the number of line and fabric card modules, for example, installed in the rack chassis increases, the number of circuit breaker modules and related connections to the monitoring card also increases, having a further detrimental effect on the reliability of the data sent by the monitoring card.  
           [0010]    What is clearly needed, is an improved method and apparatus for protecting circuits in a scalable modular chassis that provides reliable intelligence for remote monitoring of basic status and functions of the circuit breaker system, while supplying highly reliable, redundant power output for distribution to other parts of the host system.  
         SUMMARY OF THE INVENTION  
         [0011]    In a preferred embodiment of the present invention a replaceable circuit breaker module is provided, comprising a housing for supporting and enclosing elements of the module, a circuit breaker mounted in the housing in a manner that an action of installing the module connects the breaker to bridge an incoming and an outgoing conductor, and monitoring circuitry for monitoring characteristics of the circuit breaker, the monitoring circuitry mounted in the housing and having a first connector element for engaging a mating connector element in the action of installing the module. The module is characterized in that action of withdrawing the circuit breaker module also withdraws the monitoring circuitry.  
           [0012]    In preferred embodiments the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the module is configured as a docking module for docking in a bay of a cabinet to be powered, and the installation action is an action of docking the module in the docking bay.  
           [0013]    In some embodiments there is a safety mechanism for preventing the module from being docked or withdrawn with the breaker on. The safety mechanism may comprise a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module.  
           [0014]    In another aspect of the invention an electronic cabinet having a redundant power supply is provided, comprising a redundant power unit having docking bays for two or more breaker modules, a first conductor delivering power to the power unit from an external source, and a second conductor delivering power from the power unit to elements in the cabinet from the power unit. Each breaker module comprises a housing for supporting and enclosing elements of the module, a circuit breaker mounted in the housing in a manner that an action of installing the module connects the breaker to bridge first and the second conductors, and monitoring circuitry for monitoring characteristics of the circuit breaker, the monitoring circuitry mounted in the housing and having a first connector element for engaging a mating connector element in the action of installing the module, such that action of withdrawing the circuit breaker module also withdraws the monitoring circuitry.  
           [0015]    In some embodiments of the cabinet the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the module is configured as a docking module for docking in a bay of a cabinet to be powered, and the installation action is an action of docking the module in the docking bay.  
           [0016]    In some embodiments the cabinet further comprises a safety mechanism preventing the module from being docked or withdrawn with the breaker on. The safety mechanism may be a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module. The cabinet may be dedicated to a packet router in the Internet.  
           [0017]    In yet another aspect of the invention a method for improving reliability of a redundant breaker system for an electronic cabinet is provided, comprising the steps of (a) providing two or more breaker modules configured, when installed, to bridge the same two power buses; and (b) providing breaker monitoring circuitry with each of the two or more breaker modules, the monitoring circuitry configured to be removed and replaced with the breaker modules, such that monitoring circuitry is replaced whenever a breaker module is replaced.  
           [0018]    In some embodiments of the method the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the modules are configured as docking modules for docking in bays of the cabinet to be powered, and the installation action is an action of docking the module in the docking bay. In some cases the modules further comprise a safety mechanism preventing the modules from being docked or withdrawn with the breaker on. The safety mechanism may be a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module.  
           [0019]    In various embodiments of the present invention taught in enabling detail below, for the first time a breaker module is provided having built-in monitoring circuitry, such that the monitoring circuitry gets replaced whenever a module is replaced.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0020]    [0020]FIG. 1 is a perspective view of a circuit breaker assembly containing circuit breaker modules according to an embodiment of the present invention.  
         [0021]    [0021]FIG. 2 is a perspective view of detail A of FIG. 1, enlarged to show greater detail.  
         [0022]    [0022]FIG. 3 a  is a front perspective view of a circuit breaker module of FIG. 1.  
         [0023]    [0023]FIG. 3 b  is a rear perspective view of the circuit breaker module of FIG. 3 a.   
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    Internet routing service providers wishing to achieve the highest traffic-handling capability possible with current technology and methods, must possess and maintain computer equipment for data routing and switching that is capable of handling an ever-increasing amount of data traffic, while keeping routing system operating downtime to an absolute minimum, even during upgrades or repairs. An operator of such equipment must be capable of quickly and easily increasing data-handling and power distribution capacity to the system as needed, and must also be constantly informed of the status of the system while in operation, particularly the power distribution and circuit breaker system. Failures or malfunctions occurring in any part of the power distribution or circuit breaker systems, or incorrect status data sent by a malfunctioning circuit breaker sensing system make on his a monitoring worker or technician to misdiagnose a problem, for example, and may result in damaged hardware and a pronounced detrimental effect on the up-time availability of the Internet data routing system.  
         [0025]    [0025]FIG. 1 is a perspective view of a circuit breaker assembly  101  containing circuit breaker modules according to an embodiment of the present invention. Assembly  101  functions as the power distribution assembly for a rack system where it is used, and is similar to a standard rack-mountable assembly designed for use with common rack chassis configurations, such as those used for Internet routing equipment, as is the case in this example. Assembly  101  in this embodiment is of rectangular box-like shape and is manufactured of sheet metal or other similar material commonly used in the art, and has, in this example, a total of two rectangular openings, hidden in this view for reasons of simplicity, on the front face, to accommodate insertion and mounting of one or more slide-in circuit breaker modules  102 .  
         [0026]    Circuit breaker modules  102  are designed to fit and slide into separate internal bays provided at each of the front openings. A total of two openings and bays exist in the embodiment presented, however in other embodiments a varying number of openings and bays may exist providing accommodations for an equal number of circuit breaker modules. At each end of assembly  101 , facing to the outside, there are entrance interfaces for power cables bringing power to the assembly. In this example each of these entrances comprises a structure  104  with openings shown for entrance of power cables. Assembly  101  has a rectangular-shaped opening  105  located on one side towards the rear of the assembly, allowing passage of one or more power cables for supplying DC power from this breaker assembly to power-using elements in a cabinet (not shown) served by the breaker assembly described herein.  
         [0027]    The incoming cables carry the power supplied by a battery room, which converts the primary power of the facility to an intermediate DC voltage at a relatively high amperage capability. The supplied power typically is safeguarded from disruption or failure by a battery backup system in the battery room. Outgoing cables via opening  105  carry power to the power-using elements protected by the breaker assembly.  
         [0028]    The breaker system described herein connects the incoming and the outgoing power cables to provide power to chassis components from the power room in a manner designed to maximize uptime and circuitry protection.  
         [0029]    Circuit breaker modules  102  are modular units that can be inserted into, and removed from the earlier described bays within assembly  101 . The connection described between the previously described incoming and outgoing power cables within assembly  101  is served by both circuit breaker modules  201  in tandem, providing a redundant power supply, and an ability to hot-swap the modules in case of need for repair or upgrade. New and novel functionality has been incorporated into circuit breaker modules  102 , which is shown in additional drawings and described below in greater detail.  
         [0030]    [0030]FIG. 2 is a perspective view of region A of FIG. 1, enlarged to show greater detail. Elements of one of the circuit breaker modules  102 , and a portion of assembly  101  are seen more clearly in this view. Circuit breaker module  102  has a circuit breaker  103  mounted on front face  107  of circuit breaker module  102 . Circuit breaker  103  is a standard circuit breaker, having a toggle  120  extending outward from front face  107 , used for turning circuit breaker  103  on or off. As is standard, circuit breaker  103  is configured for operation with voltage at certain amperage, so that if an electrical short or power overload occurs circuit breaker  103  turns itself off, and toggle  120  goes automatically to the off position.  
         [0031]    Circuit breaker  103  is shown in this view in the on position, with toggle  120  in the upward position. A locking bar  124 , of a length slightly longer than the width of front face  107 , is provided to prevent extraction of a circuit breaker module while the breaker is on. Bar  124  is retained in the upward position by a pair of spring-loaded detents  122 . The detents are provided because the toggle is sensitive, and could be tripped by the weight of the locking bar if the bar were to rest on the toggle. Locking bar  124  at its outboard ends is restrained by a pair of end brackets  110  which are located at either end of and attached to front face  107 . Each end bracket  110  has a vertical elongated slot  111 , extending completely through and having a width slightly larger than the diameter of locking bar  124 . The height and width of slots  111  are such that the opposite ends of locking bar  124  are allowed to extend through end brackets  110  and protrude slightly beyond their outer edges, allowing locking bar  124  to travel vertically in both directions within slots  111 , while minimizing forward and backward horizontal movement. In this way locking bar  124  can assume an upper or lower position. Locking bar  124  has a pair of stop washers  121  in this example, secured to locking bar  124  semi-rigidly near the opposite ends near end brackets  110 . The purpose of stop washers  121  is to prevent side-to-side movement of locking bar  124 , thereby preventing it from slipping out of slots  111 .  
         [0032]    A locking bracket  115  can be seen in this view positioned closely to the left end bracket  110 , and is permanently attached to the face of assembly  101 . Locking bracket  115  is slightly larger and shaped similarly to end brackets  110 , and has a notch, obscured from view by the left end bracket  110 , located on the lower edge, designed to securely hold the end of locking bar  124  protruding out from end bracket  110 , when locking bar  124  is in the upper position (breaker is on). The purpose of locking bar  124 , end brackets  110  and locking bracket  115  is to provide a manual locking system that prevents the circuit breaker module from being removed from assembly  101  while current is flowing through the associated breaker.  
         [0033]    With circuit breaker module  102  fully inserted into assembly  101 , circuit breaker  103  is shown in this view with toggle  120  in the upward position indicating a powered-on condition. When moved to the upward position toggle  120  pushes the locking bar to be held by detents  122  guided by slots  111  of end brackets  110 , and in this position the left end of locking bar  124  rests within and is secured by the notch on the lower edge of locking bracket  115 . Circuit breaker module  102  is thus prevented from being pulled out of assembly  101  by the notch in locking bracket  115 , which is now securing the left end of locking bar  124 . As mentioned previously, the purpose of the locking system described, comprising locking bar  124 , end brackets  110  and locking bracket  115  is to prevent circuit breaker module  102  from being extracted from assembly  101  while the power is on, providing a safeguard against possible electrical arcing and the hazards and damage that may result.  
         [0034]    In order to remove circuit breaker module  102  from assembly  101 , circuit breaker  103  must first be turned off by manually pushing down upon locking bar  124  or toggle  120  of circuit breaker  103 . Locking bar  124  must assume the lower position guided by slots  111  of end brackets  110 . With locking bar  124  in the lower position, and toggle  120  then in its off position, the left protruding end of locking bar  124  is positioned below the notch on the lower edge of locking bracket  115 , allowing circuit breaker module  102  to be extracted from assembly  101 . Handle  108 , attached to front face  107 , is used to remove or insert circuit breaker module  102 . Two standard fasteners  119  requiring a tool for manipulation, each mounted on, and extending through front face  107 , are positioned slightly above the contact points between handle  108  and front face  107 . Fasteners  119  screw into threaded holes in assembly  101 , rigidly securing a fully inserted circuit breaker module to assembly  101 .  
         [0035]    The configuration of the locking system described above also prevents circuit breaker module  102  from being inserted into assembly  101  while toggle switch  120  of circuit breaker  103  is in the upper, or on position. Full insertion of circuit breaker module  102  into assembly  101  requires that first, toggle switch  120  be moved to the lower, or off position, moving locking bar  124  to assume its lower position, placing the left protruding end of locking bar  124  below the notch on the bottom edge of locking bracket  115 . If an attempt is made to fully insert and seat circuit breaker module  102  into assembly  101 , and toggle  120  is in its upper, or on position, the left protruding end of locking bar  124  will make contact with the front edge of locking bracket  115 , preventing full insertion.  
         [0036]    [0036]FIG. 3 a  is a front perspective view of circuit breaker module  102  of FIG. 2. In this view circuit breaker module  102  is shown outside of assembly  101 . A breaker box  125 , forming a body portion of circuit breaker module  102 , is the portion inserted into assembly  101  of FIG. 2 and was not shown in FIGS.  1  or  2 . Breaker box  125  is manufactured of sheet metal or other material similar to that used for assembly  101  of FIG. 2, and is box-like in shape and rigidly constructed to form a sturdy partial enclosure, securely attached to front face  107 . Breaker box  125  comprises a top and bottom wall and two side walls, one side wall slightly longer than the other in this example, extending back from front face  107 . The backside of breaker box  125  is open to allow for connections to be made between the breaker associated with breaker box  125  and receptacles for posts of the breaker. The receptacles a connected to incoming and outgoing power cables.  
         [0037]    [0037]FIG. 3 b  is a rear perspective view of circuit breaker module  102  of FIG. 3 a.  In this view the inner cavity formed by the body of breaker box  125  is apparent, and circuit breaker  103  is shown attached to the inner side of front face  107 . Circuit breaker  103  is of a type standard in the industry, having a pair of posts  126  providing the connection between circuit breaker  103  and the previously mentioned power-in and power-out cables. Each breaker post  126  has a circular, spring-loaded skirt  130 , a standard feature for such circuit breakers, that is manufactured of highly conductive material. Skirts  130  are compressed into the body of circuit breaker  103  when the posts are inserted into a receptacle.  
         [0038]    A redundant power supply system is achieved by insertion of a second circuit breaker module  102  into assembly  101 , the second circuit breaker having a first and second post that each plug into receptacles connected to either of power-in or power-out cables. Connection between the power-in and power-out cables is served by both inserted circuit breaker modules  102 , which are each capable of sustaining the load independently, thereby powering the cabinet by two circuit breaker modules  102  between the cables.  
         [0039]    A new and novel feature is provided in this embodiment for sensing the operational status and other conditions of circuit breaker  103 . A monitor card  128  is provided, in this embodiment as a printed circuit board, with circuitry (in this example) for sensing the presence of a circuit breaker  103  in circuit breaker module  102 , whether circuit breaker  103  is turned on or off, and what voltage is being supplied to circuit breaker  103  by the power-in cable. Monitor card  128  is mounted to the inside wall of breaker box  125 , and has a multi-pin connector element  132  which plugs into a mating connector (not shown) connected to conductors in the served chassis that lead to a monitoring interface, where the information provided by card  128  may be displayed or used for automatic monitoring purposes.  
         [0040]    When circuit breaker module  102  is fully inserted into assembly  101  and circuit breaker posts  126  engage the receptacles connected to the power-in and power-out cables, an electronic connection is simultaneously made between receptacle  132  of monitor card  128 , and the mating connector (not shown) mounted within the served cabinet. During operation, monitor card  128  sends the sensed data of the mentioned aspects of circuit breaker  103  to a computer, PC, or other monitoring device so that a worker or technician can monitor all of the functions, or the functions can be monitored automatically.  
         [0041]    A key advantage over systems of current art is provided by hosting the intelligence of the monitoring card within the circuit breaker module  102  as taught in this embodiment. In current systems, wherein the monitoring circuitry is located in the served cabinet, much time may have passed since the last replacement of the monitor circuitry, raising the possibility that a malfunction may occur in the monitoring circuitry. If such a malfunction occurs, a worker or technician monitoring the circuit breaker status may see incorrect information provided by the faulty monitoring circuitry, such as incorrect voltage, or the circuit breaker is on or off, for example, which may cause the worker or technician to take unnecessary or incorrect action to rectify the problem. Even more seriously, there may be automatic systems that react to false indications, causing unnecessary interruption of service and downtime. The problem condition indicated by the monitoring card may be due to a failure in the monitoring card, and may not be necessarily a true condition.  
         [0042]    In systems utilizing embodiments of the present invention, if monitored data indicates a power-related problem at the circuit breaker, and replacement of the circuit breaker module is the preferred solution to rectify the problem, the circuit breaker module and monitor card are replaced at the same time as one unit. In this way it does not matter so much if the data indicating the problem is a true condition, or the condition was falsely reported by a failure in the monitoring card, because the entire module along with its intelligence is replaced. When a new intelligent circuit breaker module is installed, a higher level of reliability will exist that the sensed data sent for monitoring is correct, because the new circuit breaker module  102  also has a new, tested monitoring card  128 .  
         [0043]    It will be apparent to one with skill in the art that in other embodiments of the present invention, power redundancy can be increased by installing additional intelligent circuit breaker modules  102  in assembly  101 , and in other alternative embodiments assembly  101  may have a varying number of bays for installing additional circuit breaker modules. It will also be apparent that the present invention may be used in a wide variety of electronic cabinets. In still other alternative embodiments the circuit breaker module intelligence may have the capability of sensing additional functions or status related to power operation, such as amperage, component temperature, and so on, without departing from the scope and spirit of the present invention. For these reasons that the present invention should be afforded the broadest possible scope based on the claims that follow.