System and method of mounting current transducers in proximity to circuit breakers

The present disclosure provides a method and system for mounting a current transformer in proximity to a circuit breaker of an electrical system. Generally, a sensor assembly contains a plurality of current transformers (CTs) for measuring power wires from a main power supply. To accommodate measuring a greater number of wires than one sensor assembly can service, a plurality of sensor assemblies can be mounted end-to-end. The sensor assemblies can have symmetrical recessed portions that laterally align when mounted end-to-end by inverting one of the sensor assemblies. The lateral alignment allows CTs mounted lateral to the recessed portions to be aligned with corresponding circuit breakers, so that wires passing from the circuit breakers are aligned with the CTs, reducing bending stresses on the CTs in contrast to prior efforts. Changes in polarity caused by the inversion can be adjusted by software, firmware, hardware or a combination thereof.

FIELD

This disclosure relates to electrical power systems. More specifically, the disclosure relates to methods for power distribution and electrical protection for electrical power systems.

BACKGROUND

In many premium power applications and power distribution systems, it is desirable to monitor individual branch circuit currents that distribute power from a main line to various circuit loads in an electrical system. An operator can be informed as to which connected loads are in operation, whether connected equipment is idling or fully operating, and whether any individual circuit is approaching overload and should be remedied.

In collecting data from many scattered circuit loads, current transducers (CTs) are often mounted in the system to gather current flow information. A typical mount is within the circuit breaker panel enclosure, where multiple branches from circuit breakers in the panel can be conveniently monitored from a single location. Thus, a main power supply enters the circuit breaker panel and the power is split into multiple branches having circuit breakers protecting each branch. The CTs are mounted electrically downstream of the circuit breakers in a long circuit board placed adjacent the circuit breakers. In many industrial or data center applications, the connected loads are rarely turned off to be serviced or repaired. Consequently, the reliability of the CTs with their respective board must be very high, since the CTs are toroidal in nature and cannot be removed without disconnecting circuit wiring and interrupting critical power to loads.

In application, relatively thick wire is fed from the electrical load into the circuit breaker panel, through the appropriate CT for a particular branch, and then into the contacts for the circuit breaker. However, there are several challenges. For example:1. The standard 42-pole panel for circuit breakers has limited space within its housing, typically resulting in the CT board with the corresponding CTs being made long and thin and thereby mechanically weak. Stability and integrity of the system is compromised by the relative weakness of the CT board.2. High voltage terminations at the individual circuit breaker outputs are very close to exposed current sensor soldered connections and thereby risk dangerous voltages entering the low-voltage control circuit wiring and destroying aspects of the electrical circuit and/or creating a safety hazard.3. Typical CT boards require many extra soldered connections, directly lowering reliability and performance due to lack of mechanical strength.

Branch circuit monitors to date, such as those disclosed in U.S. Pat. Nos. 6,330,516 and 6,809,509, have been built on printed circuit boards and thereby posses the disadvantages listed above. The circuit board is thin and tends to flex as thick branch circuit wires pass through the mounted CTs and can break the soldered connections, seriously impairing the performance of the branch circuit monitor.

For example,FIGS. 1A and 1Bare schematic front and end views, respectively, of a prior art arrangement. A circuit breaker panel2contains a circuit breaker assembly4having a plurality of circuit breakers6,8. Conductive wires10,12(relatively thick wires depending on the power requirements) feed power from the circuit breakers to loads14,16. A circuit board20having CTs22,24mounted thereon is used to measure current of the wires10,12passing through the CTs22,24between the circuit breakers and the loads. The CTs can eventually connect to an output connector18starting with an output wire26from the CT coil wire that is soldered to a pin28at a soldered connection32. The CT with the pin is assembled to the circuit board20by generally extending the pin28through a hole in the circuit board and soldering the pin to the circuit board at a soldered connection34. The soldered connection34is in turn connected to a circuit board line (not shown) formed on the circuit board20that leads to another soldered connection at the output connector18. A ribbon cable (not shown) can connect to the output connector18to carry output from the individual CTs to a monitoring system.

Each CT conductive path to the output connector has therefore three soldered connections and each CT has two wires for a total of six soldered connections per CT. Generally, there are 21 CTs on a circuit board for 21 circuit breakers, resulting in at least 126 soldered connections per board. For the modern trend of a circuit breaker panel having 42 circuit breakers in line, there are 252 soldered connections for such a typical circuit board branch monitoring system.

The bending stress30caused by pulling the thick wires10,12through the CTs is concentrated on the CTs22,24and its soldered connections, such as connection28, resulting in damage to the unit and therefore the system, more frequently than is desirable. Also, connections on the circuit board are exposed to dangerous voltages from the relatively close wires10,12.

Therefore, there remains a need for improvement in the method of mounting and monitoring branch distribution power in such power applications and related systems.

SUMMARY

The present disclosure provides a method and system for mounting a current transformer in proximity to a circuit breaker of an electrical system. Generally, a sensor assembly contains a plurality of current transformers (CTs) for measuring power wires from a main power supply. To accommodate measuring a greater number of wires than one sensor assembly can service, a plurality of sensor assemblies can be mounted end-to-end. The sensor assemblies can have symmetrical recessed portions that laterally align when mounted end-to-end by inverting one of the sensor assemblies. The lateral alignment allows CTs mounted lateral to the recessed portions to be aligned with corresponding circuit breakers, so that wires passing from the circuit breakers are aligned with the CTs, reducing bending stresses on the CTs in contrast to prior efforts. Changes in polarity caused by the inversion can be adjusted by software, firmware, hardware or a combination thereof.

The disclosure provides a sensor assembly for wiring in an electrical system, comprising: a sensor support having a recessed portion formed on at least one end of the sensor support and adapted to interface with an adjacent sensor support having a symmetrical recessed portion so that the recessed portions laterally overlap when the sensor supports are mounted end-to-end; and a plurality of current transformers coupled to the sensor support, with at least one current transformer mounted lateral to the recessed portion, the current transformers having apertures adapted to allow wiring to pass therethrough in alignment with one or more circuit breakers mounted in proximity to the sensor support.

The disclosure also provides an electrical system, comprising: an electrical panel; a plurality of circuit breakers coupled to the electrical panel at an incremental spacing relative to each other; a first sensor support having a recessed portion formed on at least one end of the first sensor support; a second sensor support having a recessed portion formed on at least one end of the second sensor support and adapted to interface with the recessed portion of the first sensor support by inverting the second sensor support to allow lateral alignment of the recessed portions when the sensor supports are mounted end-to-end adjacent each other; and a plurality of current transformers coupled to the sensor supports, with at least one current transformer mounted lateral to at least one recessed portion of the first and second sensor supports, the current transformers having apertures adapted to allow wiring to pass therethrough in alignment with corresponding circuit breakers at the incremental spacing when mounted in proximity to the sensor supports.

DETAILED DESCRIPTION

FIG. 2is a schematic front view of an exemplary prior art electrical branch monitoring system. The electrical system40generally includes a circuit breaker panel42having an internal space that houses a circuit breaker assembly44mounted thereto. The circuit breaker assembly44includes one or more circuit breakers, such as circuit breakers46,48,58,60, and68. Generally, the circuit breakers are aligned in pre-established spaces on a circuit breaker assembly. It is customary for the electrical circuit breaker assembly to have 21 spaces for circuit breakers in a vertical alignment. Sometimes the circuit breaker assembly has a similar arrangement to the side of an additional 21 possible spaces for other circuit breakers. Recently, some circuit breaker panels and associated circuit breaker assemblies have a vertical alignment of 42 circuit breakers for a more compact installation. The circuit breakers are generally numbered1-21or1-42on the panel to facilitate ready identification for maintenance, monitoring, or other functions. One or more electrical loads54,56,98are coupled to the circuit breakers through one or more wires50,52,88. The wires provide power to the electrical loads.

The diagram illustrates one exemplary main power supply100providing power to the circuit breaker panel42. It is known to those with ordinary skill in the art that for different power requirements, such as 240 volts, that two power feeds are required with one neutral, and for a 3-phase power system, three power feeds are required with one neutral, and other arrangements. For multiple power feeds, multiple circuit breakers can be coupled together for each circuit breaker connected to separate power feeds for a given electrical load. Thus, the present disclosure contemplates such arrangements and is specifically included within the scope of the disclosure and the claims that follow.

One or more sensor assemblies61,63, such as sensor modules to be further described below, can be generally disposed between the circuit breakers and the loads. Other sensor assemblies can include circuit boards, as modified herein, and other structures (herein “sensor supports”) that can support one or more current transformers or other sensors attached thereto. Generally, the sensor assemblies61,63will be mounted inside the circuit breaker panel42for safety, security, and protection of the sensor assemblies. The sensor assemblies can interface with each other in an interface area66described in more detail below. The sensor assemblies61,63will generally include a plurality of circuit transformers (CTs), such as CTs70,72,74,78. In general, a CT is a wire wound toroidal coil on a conductive or nonconductive core. While it is envisioned that current transformers will be the principle sensor used on a sensor assembly, other types of sensors, such as voltage, power and other sensors, are included, and thus the term current transformer is used broadly to include such sensors. The CTs can have an aperture formed within the CT through which a power wire, such as wire50, can be routed therethrough. The CTs can be specially coupled to the sensor assemblies as described below to reduce the bending stress caused by the wires50,52,88, passing through the apertures of the respective CTs. As described herein, at least one embodiment of the sensor assemblies61,63, such as the sensor modules62,64, avoids the prior art problems of relying upon the CTs to absorb the bending stress30, shown inFIGS. 1A,1B.

Further, the sensor assemblies61,63can include output connectors that can be coupled to a processor. For example, a first sensor assembly61can include a first output connector80. The connector can be a multi-pin connector, used in electronic connections, having as many as 50 pins or more, to which the various wires from the sensors can be connected. The connectors can be coupled to the sensor assemblies through the underside of the sensor assemblies so that a corresponding connector can be inserted from a backside of the breaker panel. The connector80is shown schematically inFIG. 2and is related to the position of an output connector block81shown inFIG. 3in one embodiment. Alternatively, the connector80can be positioned on the front of the sensor assembly, on an end, or at other orientations as may be convenient. The first output connector80can be coupled to a monitoring system91, having various components such as a processor90, through a cable84. In general, the output connector80will have output terminals for each of the CTs on the sensor assembly. Thus, cable84could be a ribbon cable, or other type of cable, such as an optical fiber cable, capable of discriminating between the outputs of different CTs. Similarly, a second sensor assembly63can likewise include an output connector82that can be electrically coupled to the monitoring system91, such as the processor90, through a cable86. The processor90can process the output from the CTs into various types of output, such as data, reports, or signals for further processing useful to the monitoring system and/or the operator. Furthermore, additional processors, such as processor92, can be coupled to the processor90. The processors90and/or92can include a data memory storage94and can be coupled to an output device96, such as a display, printer, transmitter, or other devices that can provide output in different formats.

In a similar fashion, the main power supply100can be coupled with a main circuit breaker102. A main supply CT104can be coupled to the main power supply100to monitor aspects of the main power supply. In some embodiments, a voltmeter106can be coupled to one or more of the electrical conductors, such as the main power supply100.

For some embodiments, where the circuit breaker assembly44includes circuit breakers1-21, the first sensor assembly61can be used with its similar arrangement of 21 CTs. In other circuit breaker assemblies that have a greater number of circuit breakers1-42, a plurality of sensor assemblies can be used, such as the embodiment illustrated inFIG. 2. The sensor assemblies61,63can be interchangeable in that they each have a similar profile and can interchange with each other. Each sensor assembly could include at least 21 CTs so that together they can serve the 42 circuit breakers. The present disclosure solves at least two challenges in so doing. First, at least one of the sensor assemblies can be inverted for the two interchangeable sensor assemblies to interface, i.e., rotated so that its bottom is the top and top is the bottom in an end-to-end fashion, such as illustrated inFIG. 2. Thus, the CTs on sensor assembly61would number1-21from the top of the sensor assembly as viewed from the perspective toFIG. 2to the bottom (i.e., from the output connector82) while the inverted sensor assembly, such as sensor assembly63, would number21-1from the top to the bottom, where the 1stCT would start near the output connectors on each sensor assembly. Software, firmware, and/or hardware coupled to the output of the CTs would have conflicting identities of two sets of 1-21 CTs, as well as one of the sets being in a reversed number sequence. Further, if the inverted CT is measuring current, the current flowing through the CTs of the sensor assembly63would be a reverse current (i.e., negative) compared to a normal flow of current (i.e., positive) flowing through the CTs of the sensor assembly61. The present disclosure can use the negative current advantageously using the software, firmware, and/or hardware the correct the CTs identities and to make adjustments for the inverted sensor support. Generally, when the monitoring system senses a reversed current, such as through the CTs of the inverted sensor assembly63, the system recognizes the negative current as an inverted sensor assembly and can remaps the identities of the CTs to correspond to the correct circuit breakers. In the illustration ofFIG. 2, the first CT of the sensor assembly63would become CT42to corresponding to the circuit breaker60. Similarly, the 21stCT of the sensor assembly63, that is CT78, would be mapped to the 22ndcircuit breaker, that is circuit breaker68, and become the 22ndCT to the monitoring system. Thus, CTs21-1would be re-identified as CTs22-42, respectively, for the inverted sensor assembly to correspond with the circuit breakers22-42. The software, firmware, and/or hardware of the present disclosure can perform such re-identification automatically.

In a similar fashion, individual CTs can indicate a reversal of current, generally inadvertently. For example, a sensor assembly could inadvertently have one or more CTs reversed during assembly and not discovered until the system is installed and operational. Likewise, one or more of the CTs can fail and need a secondary CT coupled to the respective power wire. The secondary CT could be installed inappropriately and indicate a reversed current. Thus, in a similar manner, the system can recognize the negative current as an inverted CT and translate the current as a positive current in conjunction with the other CTs associated with the sensor assembly or the system.

The second challenge solved by the present disclosure is in maintaining the spacing between the CTs and corresponding circuit breakers in the interface area66. For example, the circuit breakers58and68are generally at fixed spacing intervals, dictated by the structure, the rails, and other pre-assembled aspects of the circuit breaker assembly44. The close proximity of the spacing between the circuit breakers58,68has heretofore been problematic in abutting two prior art assemblies such the circuit boards in the patents described in the Background. The abutment would cause a misalignment between the respective CT and its circuit breaker in the interface area, causing stress on the CT and the problems described above.

The present disclosure also solves this difficulty by overlapping at least one and generally two openings formed between the sensor assemblies and the respective circuit breaker(s). For example, the circuit breaker58could be the 21stcircuit breaker in the circuit breaker assembly44and the circuit breaker68could be the 22ndcircuit breaker in the circuit breaker assembly44. Thus, both circuit breakers58,68would be in proximity to the interface area66between the two sensor assemblies61,63. The CT74having an aperture76coupled to the second sensor assembly63can be aligned with the corresponding opening75formed in the first sensor assembly61where both the aperture and the opening can align with circuit breaker58. Similarly, the CT78(e.g., the 21stCT of the second sensor assembly63) when inverted, could align with a corresponding opening79formed in the first sensor assembly61and the 22ndcircuit breaker68. The alignment between the CTs and the interface includes one or more CTs in the interface area that overlap with a corresponding opening in the adjacent sensor assembly and allows wires to pass in alignment between the corresponding circuit breaker through the sensor assembly, and to the load. For example, a wire88coupled to the circuit breaker68could pass through the CT78and a corresponding opening79in the other sensor assembly and onto an electrical load98. The CTs and openings can be on one sensor assembly, or on both sensor assemblies in the 21stposition of each sensor support.

Further, the disclosure can provide for those instances where a CT for a given wire fails to function. The present disclosure provides an alternative to disassembling the system40and the particular sensor assembly with a defective CT. The disclosure can provide a secondary CT and exclude an output of a CT coupled to the sensor assembly that otherwise would be used to monitor the conditions for that branch circuit. The software, firmware, or hardware can detect when abnormal conditions exists by for example, comparing with stored historical data or noting values lower or higher than predetermined values, and other metrics. The system can trigger an alarm, make adjustments, or otherwise alert an operator. For example, a CT160coupled to a sensor assembly could normally be used to monitor the conditions of branch wire158. If CT160fails, the processor90can provide an output indicating the condition. A secondary CT162can be coupled for example by clamping the CT to the wire158without having to disconnect the wire158. The CT162can be independently coupled to the monitoring system, such as to the processor90or a connector for the sensor assembly. The monitoring system91can exclude the output, automatically or selectively, from the defective CT160and use the output from the secondary CT162in substitution thereof and independent of the CT160.

FIG. 3is a perspective schematic view of one embodiment of a sensor module as an exemplary sensor assembly. The sensor assemblies61,63, described inFIG. 2, can comprise sensor modules62,64. In general, the term “sensor module” herein will include a sensor assembly having a relatively significant height from a plane upon which it is mounted in contrast to a circuit board with a relatively insignificant height above its plane of mounting. The sensor module generally has a sufficient height such that a wire from a circuit breaker can pass laterally (i.e., sideways) through the sensor module in contrast to the wire passing above it, as in prior efforts, measured from a plane on which the sensor module is mounted. The sensor module can advantageously be molded substantially as a unit or can be assembled from preformed sections.

The sensor module, such as the first sensor module62, also shown inFIG. 2, is illustrated on its side to show the various portions thereof. For illustrative purposes and to provide a context to the figure, the wire50, also shown inFIG. 2, is shown passing through the first CT70, although certainly other orientations are possible. In general, the sensor module includes a first surface108that can provide a supporting surface for the module on a structure to which it is coupled. A second surface109is formed at an angle to the first surface to establish a height above the first surface for the sensor module. Advantageously, the height is of a dimension such that the wire50from a circuit breaker (shown inFIG. 6) mounted adjacent the sensor module can pass laterally through the sensor module in alignment with the circuit breaker, as described herein. Related structures such as a post with an opening, described below, can be laterally coupled to the second surface along its height and reduce or avoid the bending stresses from the wire passing therethrough. This structure is in contrast to prior efforts, using for example circuit boards of relatively insignificant height, resulting in such bending stresses.

The module can include a first portion110that is sufficiently wide to mount to a structure, such as the circuit breaker panel42, shown inFIG. 2. The first portion can establish the supporting surface108. One or more mounts130, in at least one embodiment, can extend outwardly from the first portion of110as a tab with a mounting opening form and therethrough to further allow coupling of the first portion110to the panel44. Other methods of mounting the sensor module such as retainers, adhesive, or other methods are contemplated. The sensor module62further includes a second portion114disposed at an angle to the first portion110. The second portion can establish the second surface109. In at least one embodiment for commercial efficiency, the second portion114can have a thinner cross-sectional area compared to the first portion110in the same direction. For example, and without limitation, the first portion110can include a flange having a greater width than height and the second portion114could be a web having a greater height than width. The flange provides a quantity of bending stiffness to the web across its smaller cross sectional dimension (i.e., thickness166shown inFIG. 4) and the web provides a quantity of bending stiffness to the flange across its smaller cross sectional dimension (i.e., thickness168shown inFIG. 4) when the flange and web are coupled together. In at least some embodiments, the sensor module62can further include a third portion112. The third portion112can be similarly shaped as the first portion110and can also be a flange, although other shapes are contemplated. The sensor module further includes an output connector block81with an opening81A, the block being coupled to the sensor module62to allow an output connector80, shown inFIG. 2, to be assembled thereto.

The sensor module can further include a recessed portion116. In at least one embodiment, the recessed portion116is adapted to allow an adjacent sensor module to be coupled thereto to form the interface area66. Thus, the recessed portion116is generally symmetrical with the recessed portion of an adjacent module. Further, the sensor modules can be made interchangeable with each other, so that they can be inverted and still function in the intended manner as described herein.

The sensor module material can be any suitable material and if molded will be generally a polymer compound that can withstand some stresses. Advantageously, at least a portion of the sensor module is nonconductive. Exemplary materials for the sensor module are polymers, like polyesters, such as polyethylene terephthalate (“PET”), including PET (FR530), and polybutylene terephthalate (“PBT”), including PBT (4130). PBT is especially preferred since it is highly temperature resistant. Both materials are Underwriters Laboratories (UL) listed materials. Other structural materials, conductive and nonconductive can be used.

One or more CT posts for supporting the CTs can be coupled to the sensor module62. In at least one embodiment, the posts are formed integrally therewith during a molding process. The posts, such as118, have an opening150formed to allow the wire, such as wire50, to be inserted therethrough. In general, the opening150will be aligned at an angle to the second portion114. When assembled, such as shown inFIG. 2, the opening150will be aligned with its respective circuit breaker to allow the wire to be inserted through the opening and aligned with the corresponding circuit breaker. Thus, the height of the opening150above the first portion110in general will correspond to the height of the circuit breaker, such as circuit breaker46, above the height of the panel42when the sensor module62is mounted to the panel42. In at least one embodiment, the sensor module62can have 22 posts coupled thereto. The posts can allow for the customary 21 circuit breakers with the 22ndpost to be used in conjunction with an adjacent sensor module. More specifically, 21 posts in the sensor module62could have CTs (shown inFIGS. 4,5) mounted thereto. In the embodiment shown inFIG. 3, the CTs could be disposed on any post between post70to post126for any correspond circuit breakers in the circuit breaker panel. Post124could be used to overlap with a CT mounted on a post of an adjacent sensor module (shown inFIG. 6) in the corresponding position as post126is on the first sensor module62. Thus, an overlapping post124having an opening125has a general utility of allowing wire coming through a corresponding CT on an adjacent module through the opening125that can continue to the corresponding electrical load, such as shown inFIG. 2.

The posts can generally be aligned at a consistent vertical height to correspond to the height of the circuit breakers. Further, the spacing between the posts, such as posts118,120, are generally at the same spacing as the circuit breakers in the circuit breaker panel to maintain an alignment with the wires passing therethrough to the circuit breakers. The alignment helps reduce stresses on the wiring that in turn reduces stresses on the sensor module and circuit breakers. However, the general diameter of a CT is larger than can be accommodated with the restricted spacing between the posts. Thus, the CTs can be assembled to the sensor module in an alternating fashion as shown inFIGS. 4,5described below. To assist in accommodating the alternating arrangement, a step122can be formed or otherwise coupled on one or more posts to restrict the axial (i.e. lateral relative to the second portion114) movement of the CT along the length of the post. For example, post120can be coupled with a step122. Advantageously, the steps are included on alternating posts to assist in appropriate placing of the CTs for the particular post. In the interface area66, the step can be provided by surface128to restrict the axial movement of the CT along the axis of the post.

FIG. 4is a cross sectional schematic view of the sensor module ofFIG. 3with a post and a current transformer coupled thereto. The cross section is shown through the post118ofFIG. 3and through a portion ofFIG. 6with the addition of a CT and relevant wiring. The sensor module62generally includes a first portion110, such as a flange, a second portion114, such as a web, and in some embodiments, a third portion112, such as an additional flange. In general, the first portion110can provide a mounting surface to some support structure, such as the circuit breaker panel42, shown inFIG. 2. One or more mounts130can facilitate the mounting of the sensor panel62to a support structure. The shape of the sensor module62can vary significantly in size, height, orientation, relative widths, and thicknesses, and the illustration is only exemplary. In general, however, the sensor module will have a first portion of some dimensions and a second portion of some dimensions coupled to the first portion at some angle thereto so that an opening150formed through the second portion114can be adapted to align with the corresponding circuit breaker (shown inFIGS. 2,6). This “height” above a plane on which the sensor module is mounted that is sufficiently high to allow the CTs to be laterally coupled thereto reduces the bending stresses on the CTs in contrast to bending stresses on the CTs mounted as shown inFIG. 1B. The post118can be formed integrally with the sensor module, such as by molding therewith, or otherwise coupled to the sensor module62and in general could be formed with the second portion114. Importantly, the post118can absorb bending stress146caused by the wire52bending or otherwise attempting to misalign the opening150with the sensor module62. Further, the posts transfer bending stresses from wires passing through the posts to the second portion114coupled with the posts, so that the second portion incurs stress in a shear stress mode that would tend to otherwise tear the second portion material. A shear stress mode can be structurally accommodated by the thickness of the second portion sufficient to resist tearing from the bending stresses. Thus, the connections of the CT to the sensor module are generally not unduly stressed, absent a catastrophic failure of the coupling portion of the sensor module, such as the posts with the CTs separating from the sensor module.

A CT72can be disposed about the post118. In at least one embodiment, the CT72will be disposed around the post118, so that the wire52is not in direct contact with the CT72, that is, the post118provides a buffer structure between the CT72and any wire disposed through the opening150. Thus, the CT78disposed distally from the wire52is generally not exposed to undue stress146as in prior efforts. If the post118does not have a step, as described inFIG. 3, then the CT will generally be disposed in proximity to the second portion114.

Generally, the CT has a pair of output wires136to provide an output signal to the monitoring system, shown inFIG. 2. In at least one embodiment, the output wires136can be directly coupled to an output connector80without intermediate soldering connections other than at the output connector. Thus, the typical 126 soldering connections for 21 CTs found in prior art can be reduced to 42 soldering connections, a 67% decrease in soldering connections. It is believed that this reduction will result in inherently less failures. To facilitate the output wires136for each CT traveling to the connector80, a wire channel134can be formed in the sensor module62. For convenience, the wire channel134can be formed in the first portion110. The number of output wires in the channel will vary depending upon the particular entry of the respective CT to the wire channel. In general, the maximum expected number of output wires in the wire channel will be about 42 to correspond to two output wires for 21 CTs, in at least one embodiment. Further, the wire channel134can be filled with an insulative material to seal the output wire from the CTs in the wire channel. Thus, the present disclosure provides an increased safety margin over prior art by maintaining the wire52carrying the power to the electrical load away from both the CT by way of the post118and the output wire136from the CT to a separate and in some cases sealed wire channel134, with an attendant reduction in the number of solder connections and failure rates.

FIG. 5is a cross sectional schematic view of the sensor module ofFIG. 3with a stepped post and a current transformer coupled thereto.FIG. 5is illustrative of the cross section of the sensor module shown inFIG. 3andFIG. 6passing through a stepped post120, having a step122, with the addition of a CT and relevant wiring. Similar to the description regardingFIG. 4, the sensor module62includes the first portion110, the second portion114, and a third portion112, in at least some embodiments. A post120is generally coupled to the second portion114, where the post120has an opening formed therethrough that is generally aligned with a circuit breaker, such as the circuit breakers shown inFIGS. 2,6. The post120can include a step122. In some embodiments, the step can be formed integrally with the post120and in other embodiments, the step can simply be a cylinder or other geometric shaped component inserted at least partially around, over, attached to, or otherwise coupled with the post120. In general, the step122will restrict the movement of a CT, such as CT70, coupled to the post120in a direction along the axis of the opening through the post. The offset distance caused by the step122away from the second portion114on the post120can correspond to and allow for close spacing of the post118, described inFIG. 4, and its respective CT72to maintain an axial alignment with circuit breakers at their close spacing. Output wires132extending from the CT70can be routed to and through the wiring channel134(shown inFIG. 4) that in at least one embodiment can be formed in the first portion110. In this embodiment, similar to the embodiment shown inFIG. 4, the post120can isolate the CT70from the wire passing through the post120. The isolation can occur electrically as well as mechanically, such that a bending stress146caused by the wire is generally absorbed by the post120and not the CT70. Thus, the CT70and its output wires132are generally protected and subject to less system failure. The sensor module further includes an output connector block81with an opening81A, the block being coupled to the sensor module62to allow an output connector80, shown inFIG. 2, to be assembled thereto.

FIG. 6is a perspective schematic view of interfaced sensor modules between a plurality of circuit breakers and respective electrical loads. A first sensor module62can interface with a second sensor module64. The second sensor module64can be interchangeable with the first sensor module62. Each module can include an output connector80,82, respectively. The second sensor module generally will have a similar structure to the first sensor module so that it includes a first portion110A, a second portion114A, and a third portion112A. Generally, the first and third portions will be a flange having a wider base than height and the second portion114A will be a web having a larger height than width (i.e., thickness of the section). The first, second, and third portions can be molded as an integral unit in at least some embodiments. Further, the second sensor module will generally have a plurality of posts as has been described above and can be coupled to a support structure by, for example, coupling the first portion110A to an electrical panel, shown inFIG. 2, and in some embodiments facilitated by a mount130A.

The first sensor module62can include a recessed portion116that can be coupled to a corresponding recessed portion116A of the second sensor module64in the interface area66.

One or more circuit breakers58,68,108can be disposed in the electrical system40. Generally, the circuit breakers will be disposed at a fixed relative spacing or an increment thereof. The spacing is generally determined by the factory-installed rails138and the spacing between the rails. The rails form a supporting surface for the circuit breakers to be inserted and generally clipped on or screwed thereto. For example, the rail138to which the circuit breaker58can be coupled thereto, is spaced at a unit spacing142from an adjacent rail140to which the circuit breaker68is coupled thereto. The electrical system may not require a circuit breaker to be coupled to rail148and may skip an interval to a rail152disposed at a spacing144, incremental to the spacing142. Generally and without limitation, the incremental spacing will occur in integers, such as one spacing, two spacings, and so forth, although fractional increments can be used, such as one-half and one-third spacings. The circuit breaker108coupled to the rail152can connect to a wire passing through the second sensor module for an electrical load154. A wire88can be disposed between the circuit breaker68and a load98. Similarly, a wire can be disposed between the circuit breaker58and a load156. Generally, each wire will pass through a corresponding CT mounted in either the first sensor module62or the second sensor module64. In the interface area66, the wire could and generally does pass through both recessed portions of the sensor modules62,64. For example, in at least one embodiment, post124A,126A formed in the recessed portion116A of the second sensor module64could be aligned with and overlap corresponding posts on the recessed portion116of the first sensor module62, as described in reference toFIG. 3.

In at least one exemplary embodiment and without limitation, it is expected that the sensor modules would include 22 posts with the first 21 posts having CTs mounted thereon starting from the output connector on the end. The 22ndpost of each module would overlap with the corresponding 21stCT of the other module. For example, a CT mounted on the post126A of the second sensor module64would generally align with an opening through a post126(shown inFIG. 3) of the first sensor module62. Likewise, the post124A with its corresponding opening of the second sensor module64would align with the post126(shown inFIG. 3) and a CT mounted thereon of the first sensor module62in an overlapping fashion so that the wires from the circuit breakers to the respective loads could pass through both sensor modules in the interface area66and maintain alignment with the spacing142if circuit breakers were present in both locations.

WhileFIGS. 3-6illustrate a non-limiting embodiment of the sensor module, the sensor assembly broadly described inFIG. 2can include circuit boards and other structures that support the current transformers attached thereto.

FIG. 7is a perspective schematic view of one embodiment of a circuit board as an exemplary sensor support, having certain aspects taught in this disclosure. A circuit board176can include one or more CTs74,78coupled thereto. The CTs can be coupled to the circuit board by soldering, fastening, forming, or other means. As described above, a plurality of circuit boards can be disposed adjacent each other in an end to end fashion to provide additional capacity for servicing a larger number of circuit breakers than individual circuit boards.

To solve the above referenced issue of alignment between the closely spaced circuit breakers58,68and the CTs on the circuit boards at the ends of the circuit boards, an interface area66can be formed between the adjacent circuit boards176,178. The first circuit board176can include a recessed portion116and the second circuit board178can include a recessed portion116A, similar to the recessed portions described above in reference to the sensor modules inFIGS. 3-6. The recessed portions can be substantially symmetrical between the circuit boards to allow interchangeability when inverting one or more of the circuit boards. The CTs74,78can be mounted laterally relative to their respective recessed portions116,116A of their circuit boards. When the circuit boards176,178are mounted adjacent each other end-to-end, the recessed portions116,116A can be laterally aligned in the interface area66in a side-by-side fashion and allow the CTs74,78to maintain a relative alignment with the circuit breakers58,68. The CTs can be mounted laterally offset from each other on the circuit board to allow a closer axial spacing170between adjacent axes172,174passing through the apertures than if mounted without the offset. Such alignment would otherwise be unavailable as in prior efforts because the dimensions of the CTs have not allowed sufficiently close spacing as the dimensions of the circuit breakers. Wires78,108passing through CTs74,78, respectively, can be routed from the circuit breakers through the CTs74,78in relative alignment and lessen associated bending stresses that otherwise can cause failures in the system.

Various basics of the invention have been explained herein. The various techniques and devices disclosed represent a portion of that which those skilled in the art would readily understand from the teachings of this application. Variations are possible and contemplated and are limited only by the claims. Details for the implementation thereof can be added by those with ordinary skill in the art. Such details may be added to the disclosure in another application based on this provisional application and it is believed that the inclusion of such details does not add new subject matter to the application. The accompanying figures may contain additional information not specifically discussed in the text and such information may be described in a later application without adding new subject matter. Additionally, various combinations and permutations of all elements or applications can be created and presented. All can be done to optimize performance in a specific application.

The various steps described herein can be combined with other steps, can occur in a variety of sequences unless otherwise specifically limited, various steps can be interlineated with the stated steps, and the stated steps can be split into multiple steps. Unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of any other element or step or group of elements or steps or equivalents thereof.

Further, any documents to which reference is made in the application for this patent as well as all references listed in any list of references filed with the application are hereby incorporated by reference. However, to the extent statements might be considered inconsistent with the patenting of this invention such statements are expressly not to be considered as made by the applicant(s).

Also, any directions such as “top,” “bottom,” “left,” “right,” “upper,” “lower,” and other directions and orientations are described herein for clarity in reference to the figures and are not to be limiting of the actual device or system or use of the device or system. The device or system may be used in a number of directions and orientations.