The present invention relates generally to the field of power electronic devices such as those used in power conversion or applying power to motors and similar loads. More particularly, the invention relates to a common mode magnetic device configured to cooperate with a bus structure.
In the field of power electronic devices, a wide range of circuitry is known and currently available for transmitting, converting, producing, and applying power. Depending upon the application, such circuitry may transmit incoming power to various devices and/or convert incoming power from one form to another as needed by a load. In a typical drive system arrangement, for example, constant or varying frequency alternating current power (e.g., from a utility grid or generator) is converted to controlled frequency alternating current power that can be used to drive motors and other loads. In this type of application, the frequency of the output power can be regulated to control the speed of the motor or other device. Circuitry for providing such functionality is often packaged together. Indeed, electrical systems with packaged electrical and electronic components, such as drive cabinets and motor control centers (MCCs), are known and in use. For example, a drive cabinet may include a rectifier (converter), an inverter, transitional attachments, and so forth. Further, such electrical enclosures may include bus work that communicatively couples the components with a power source and/or other components.
Electronic components such as those discussed above are typically coupled to a power source and/or load via cabling. For example, input cabling may pass into an electrical cabinet and couple with a bus system, and output cabling from the electrical cabinet may couple with a load. This cabling is often utilized with a common mode magnetic device to improve operation of the system. For example, operation of a drive system such as that discussed above often benefits from utilization of a common mode magnetic device (e.g., a common mode core) with power input and/or output from the drive system. A common mode magnetic device may include a common mode core, which is essentially an inductor. Typically, a common mode core includes numerous loops of wire disposed about a core such that the common mode core forms a toroid. Typically, a common mode core is utilized by placing the toroid around input cables to a drive system or output cables from the drive system. When a common mode core is utilized around input cables to a drive system, it typically functions to reduce harmonics or provide a line voltage buffer. When a reactor is utilized around output cables from a drive system, it typically functions to provide a filter for reflected wave reduction.
Traditional electrical cabinets, electrical components, common mode cores, and so forth make installation and/or maintenance of common mode core features inconvenient. For example, it is often necessary to disassemble and/or rearrange certain components to place a common mode core around input or output cabling. Further, it is now recognized that it can be difficult to fish the input or output cabling through the toroidal body of a traditional common mode core. Also, positioning of a common mode core at an available location is often inconvenient. For example, due to spatial limitations, a traditional common mode core may have to be positioned in a location that exposes the common mode core to additional wear and deterioration.
Accordingly, it is now recognized that it would be desirable to develop a common mode core that can be conveniently coupled to electronic components.
According to one embodiment of the present invention, a magnetic device mounting system is provided. The magnetic device mounting system includes a common mode magnetic device, such as a common mode core, that is formed from magnetic tape wound about the perimeter of an obround mandrel. The mandrel and magnetic tape are essentially concentric about an opening through the mandrel. The system also includes a non-conductive support and a conductive extension. The non-conductive support and the conductive extension are configured such that they coordinate to engage the opening and support the common mode magnetic device via attachment to a bus bar.
According to one embodiment, a magnetic device mounting system is provided that includes a common mode magnetic device and a housing (e.g., an electrical enclosure or a drive component housing). In one embodiment, the common mode magnetic device includes a common mode core with an opening through the common mode core. Further, in some embodiments, the perimeter of the common mode core and the opening each have an obround shape. The housing includes a receptacle formed in the housing with a plurality of conductive features extending from a central portion of the receptacle, wherein the receptacle is configured to receive the common mode magnetic device such that the plurality of conductive features pass through the opening. In some embodiments, the receptacle also includes a raised portion, such as a lip, that is shaped to correspond with the opening in the common mode magnetic device such that the raised portion engages the edges of the opening to hold it in place and prevent it from contacting the plurality of conductive features.
According to one embodiment, a common mode core is provided that includes dimensions that facilitate interaction with a bus bar system. In one embodiment, the common mode core includes a mandrel having an obround perimeter. An opening is formed through the mandrel and magnetic tape is wound around the perimeter of the mandrel. The opening is sized to facilitate cooperation with the spacing of bus bars such that power from the bus bars can readily be diverted via bus bar extensions through the opening in the common mode core without requiring that cabling be drawn together and with limited adjustments.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
As discussed in detail below, embodiments of the present technique function to provide a common mode magnetic device (e.g., a common mode core) configured to conveniently function with a bus structure of a drive system or the like. In particular, the present technique relates to providing a common mode magnetic device that is configured to cooperate with bus bars or related extensions within the enclosure. For example, one embodiment includes a common mode core that is configured to surround conductive extensions from a receptacle formed in an outer wall of an electrical enclosure. The common mode magnetic device is generally obround and configured to be positioned about a plurality of conductive extensions and non-conductive supports that are coupled to respective bus bars. The conductive extensions may include elongate via blocks and/or bus extensions that each couple to the face of a bus bar such that current from the bus bar can be conducted in a direction traverse to the length of the bus bar and through an opening in the common mode magnetic device. The non-conductive supports may include plastic sleeves that surround side portions of the conductive extensions to prevent contact between the conductive extensions and the common mode magnetic device. The non-conductive supports may couple about the conductive extensions such that end portions of the conductive extensions remain exposed for coupling to the bus bars and other features (e.g., a bus bar extension or an electronic component). The non-conductive supports also include projections that engage either side of the common mode magnetic device when assembled such that the common mode magnetic device is insulated between the non-conductive supports and held in place relative to the bus bars.
References in the specification to “one embodiment,” “an embodiment,” or “an exemplary embodiment,” indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Additionally, geometric references are not intended to be strictly limiting. For example, use of the term “perpendicular” doe not require an exact right angle, but defines a relationship that is substantially perpendicular, as would be understood by one of ordinary skill in the art.
Turning now to the drawings and referring to
A set of bus bars 116 passes along a panel of the enclosure 100 and through each of the enclosure sections (i.e., the wiring bay section 102 and each of the drive sections 104, 106). The bus bars 116 are made of conductive material (e.g., copper or aluminum) that has been extruded to a desired length for use with the enclosure 100. Additionally, as will be discussed below, the bus bars 116 are extruded with certain cross-sectional features that facilitate communicatively coupling the bus bars 116 with expansion or attachments features 118 and devices, such as the projections 114 and/or a common mode magnetic device kit in accordance with present embodiments. These cross-sectional features also facilitate cooperation with a support system that couples the bus bars 116 to the enclosure 100 and provides flexibility in configuration of the bus system (e.g., expansion of bus bar capacity) without requiring substantial changes in the bus system. Indeed, each of the bus bars 116 is held in place within the enclosure 100 with a support system that includes bus support brackets that are formed or molded from a thermalset glass reinforced material or a non-conductive material to coordinate with aspects of the cross-sectional features. Specifically, as will be discussed in further detail below, the support brackets each include openings into which one of the bus bars 116 can slide. Each support bracket includes a main opening with slots that correspond to cross-sectional features of the bus bars 116 such that the bus bars 116 can be retained without being fastened to the brackets. In some embodiments, end caps or the like may be positioned near or around the ends of the bus bars 116 such that the bus bars 116 can essentially float within the brackets without substantial lateral sliding. This flexibility facilitates attachment to features, such as the projections 114 and/or a common mode magnetic device kit in accordance with present embodiments, by allowing slight movement of the bus bars 116 within the enclosure 100.
During operation of the illustrated embodiment, the enclosure 100 receives power (e.g., three-phase AC power) from a source (e.g., an electrical grid) and distributes the power to various devices, including the drive systems 104, 106. Further, the various components of the drive systems 104, 106 cooperate to provide power at a desired level to a load (e.g., a motor or pump) external to the enclosure 100. As a group, the set of bus bars 116 receive and transmit the power to various components within the enclosure 100. Different groupings of the bus bars 116 are coupled to different features within the enclosure, and, thus, perform different tasks. Indeed, the upper three bus bars 120, middle two bus bars 122, and lower three bus bars 124 of the set of bus bars 116 may each perform a different function. For example, the upper three bus bars 120 may receive input power, the middle two bus bars 122 may transmit power between drive system components, and the lower three bus bars 124 may provide output power. As indicated above, the projections 114 may serve as an input to the enclosure 100 or an output from the enclosure 100. For example, the projections 114 may couple with a power source such that input power (e.g., three-phase AC power) passes through the common mode magnetic device 112 upon entry into the enclosure 100 and is then transmitted to enclosure components (e.g., a rectifier) through the upper three bus bars 120. By passing the input power through the device 112 various benefits may be achieved, such as reducing harmonics. As another example, the projections 114 may couple with the lower three bus bars 124 that are providing output from converters of one or both of the drive systems 104, 106 within the enclosure 100. By passing the output power through the device 112 various benefits may be achieved, such as reducing the effects of reflected waves.
As illustrated in
Input and/or output power may be filtered using one or more of the common mode magnetic devices 112. In the illustrated embodiment, two magnetic devices 112 are shown to demonstrate that the devices 112 may be positioned about power transmission lines at different points in the process. While two magnetic devices 112 are illustrated in
As set forth above, the bus bars 116 provide power to various different components of the drive systems 142 and other features. This is achieved, in accordance with present embodiments, by communicatively coupling the various devices to the bus bars 116 via attachment or connection features 118. One type of connection feature, as will be discussed below, facilitates attachment of the magnetic device 112 to the bus bars 116 such that power can be transmitted through the opening in the magnetic device 112 without the magnetic device 112 conductively touching the bus bars 116. Such connection features 118 interlock with grooves in the bus bars 116 via bus clamps or the like. Due to the nature of the grooves in the bus bars 116, the connection features 118 can generally slide along the bus bars 116 and secure to any location along the bus bars 116 such that the connection features 118 can easily be positioned for connection with a device, power source, or the like. For example, using the bus bars and connection features 118, the magnetic device 112 can essentially be positioned anywhere along the face of the bus bars 116 to facilitate filtering the power transmitted through the magnetic device 112 before entering a particular component or being supplied to the load 114. By enabling attachment of the magnetic device 112 in this manner, one can readily install the magnetic device 112 from a front entry into the enclosure 100, and, thus, avoid complex rearrangement of components, disassembly of input and/or output cabling, and so forth associated with traditional systems.
It should be noted that the geometric features in the face of the bus bars 116 facilitate coupling with the magnetic device kit 200. In the illustrated embodiment, the bus bars 116 are extruded metal and can be extruded to a desired length for an application. Further, the illustrated bus bars 116 have been extruded such that particular cross-sectional characteristics are included in a face of the bus bars 116 and along the sides of the bus bars 116. These cross-sectional characteristics, as will be discussed below, facilitate installation of the bus bars 116 and attachment of fasteners extending from the connection features 202 with the bus bars 116 in accordance with present embodiments. Further, with regard to the material utilized for the bus bars 116, different metals may be used for the extrusion to provide different functionality. For example, depending on the level of power being transmitted, the bus bars 116 may be extruded from aluminum or copper. It should also be noted that
The features of the magnetic device kit 200 are more clearly illustrated in
Specifically, in the illustrated embodiment, the conductive extension 202 includes the via block 302, which is extruded, molded, or otherwise formed from conductive material. The via block has an elongate body with an obround cross-section along its length and coupling regions or interfaces 330 on either end. The interfaces 330 of the via block 302 are substantially planar faces with the integral attachment features 304 (e.g., integral bolts and/or bolt holes). As indicated above, each of the interfaces 330 is configured to communicatively couple with electrical features to facilitate transmission of power through the magnetic device 112. For example, in the illustrated embodiment, a body of the via block 302 is configured to pass through the opening 206 in the magnetic device 112, one of the interfaces 330 is configured to communicatively couple with the bus bar 116, and the other interface 330 is configured to couple with the side bus 204. Thus, the via block 302 serves as a power conduit between the side bus 204 and the bus bar 116. The interfaces 330 may include one or more different types of coupling features. For example, in the illustrated embodiment, the interfaces 330 include bolt holes 304 that extend through the body of the via block 302 and cooperate with the bolts 306 to couple with the bus bar 116 and the side bus 204. In other embodiments, the via block 302 may include integral bolts that extend away from the via block 302 as part of the interfaces 330. Further, in some embodiments, the conductive extension 210 may include different characteristics. For example, the conductive extension 210 may include the side bus 204 and the via block 302 integrated together. Such a conductive extension 210 may pass through a single support bracket that functions as the conductive support 212, through the opening 206, and couple with the bus bar 116. In such an embodiment, the conductive support 212 may be integral with the magnetic device 112 or include features that extend around the outer sides of the magnetic device 112 and along the back sides to insulate the magnetic device 112 from the bus bar 116.
As indicated above, the connection feature 202 also includes the non-conductive support 212. The non-conductive support may be formed from compression molded plastic or other non-conductive material. While in some embodiments the non-conductive support 212 may include a single piece that wraps around the magnetic device 112, in the illustrated embodiment, the non-conductive support 212 includes the first bracket 320 and the second bracket 322 that each couple together about the via block 302 and abut opposite sides of the magnetic device 112. Specifically, a first sleeve 340 of the first bracket 320 is designed to slide into a second sleeve 342 of the second bracket 322 such that the first and second brackets 320, 322 are coupled together in a friction fit or the like. These sleeves 340, 342 are sized to couple about the via block 302 and to cover the sides of the via block 302 such that it does not directly touch the magnetic device 112 during operation. As can be appreciated, different embodiments may utilize different coupling features that function like the sleeves 340, 342. Further, the sleeves 340, 342 may each include different coupling features that facilitate secured engagement with one another (e.g., flexible tabs and grooves).
As noted above, while other embodiments may include different characteristics, the illustrated via block 302 is molded, extruded, or otherwise formed such that it has an obround cross-section. That is, the perimeters of the interfaces 330 and the body of the via block 302 are obround. Accordingly, the opening 344 formed by the sleeves 340, 342 in the illustrated embodiment is obround as well. This shape eliminates sharp corners that can cause damage. Further, the rounded edges facilitate insertion of the via block 302 into the opening 344 formed by the sleeves 340, 342 without snagging corners on the edges of the opening 344 and so forth. Likewise, the opening 206 in the magnetic device 112 is correspondingly obround such that insertion of the sleeves 340, 342 and engagement with the connection feature 302 is facilitated. Further, the length of the obround shape facilitates increased power transmission capacity of the via block 302 and a structural strength of the via block 302 for supporting the kit 200.
Also, the brackets 320, 322 include features that insulate the magnetic device 112 from surrounding components. For example, the first bracket 320 includes a first projection 350 and the second bracket includes a second projection 352 that cooperate to prevent the magnetic device 112 from touching the bus bar 116, the side bus 204, or the like when assembled. In the illustrated embodiment, these projections 350, 352 are essentially planar tabs that extend perpendicularly from the sleeves 320, 322, respectively. However, in other embodiments, different types of projections 350, 352 may be used. Each of the projections 350, 352 abuts an opposite side of the magnetic device 112 when assembled about the device 112 such that the device 112 is held in place and insulated from adjacent electrical components. In the illustrated embodiment, retention of the magnetic device 112 relative to the bus bars 116 is achieved by essentially wedging the magnetic device 112 between the projections 350, 352, which are held together by the fasteners 306, which pass through the side bus 204, the connection feature 202, and engage with grooves in the bus bar 116.
With regard to the geometry groove features and so forth of the bus bar 116, it should be noted that multiple grooves 500 are employed to reduce moment of the connection feature 202 about the bus bar 116 and to facilitate uniform contact between the bus bar 116 and the via block 302. Indeed, in accordance with present embodiments, the torque present when the bus bar 116 is coupled with the connection feature 202 facilitates the provision of communicative contact between the bus bar 116 and the via block 302. It should be noted that while two grooves 500 are provided in the embodiment illustrated by
The bus bar 116 may also be extruded with ridges 512 that extend along the edges of the bus bar 116. The ridges 512 may coordinate with support features to maintain stability of the bus bar 116 within an enclosure. For example, turning back to
As indicated above in the discussion of
It should be noted that the receptacle 706 engages with a panel 710 that includes openings 711 that pass over the conductive tabs 708 such that the panel 710 engages with a rear wall of the receptacle 706. The panel 710 also includes a raised central portion or a lip 712 that is configured to engage the edges of the magnetic device 112 around the opening 206. In some embodiments, the receptacle 706 may include an integral lip or raised portion 712. The engagement between the edges of the magnetic device 112 around the opening 206 and the raise portion 712 holds the magnetic device 112 in place and prevents the magnetic device 112 from touching the conductive tabs 708. Accordingly, separate non-conductive supports may not be required. Indeed, in the illustrated embodiment, the raised portion 712 prevents horizontal or vertical movement of the magnetic device 112 relative to the conductive tabs 708. However, the magnetic device 112 can be slid along the raised portion 712 such that it disengages from the receptacle 706. Accordingly, a latch, panel, or other retention feature 714 can be fastened about the magnetic device 112 and or components of the receptacle 706 to resist or prevent such movement. In some embodiments, the magnetic device 112 may engage outer edges of the receptacle 706, which may function to prevent movement of the magnetic device 112 relative to the conductive tabs 708.
As previously indicated, the magnetic device 112 includes a generally obround shape in accordance with present embodiments. This may be achieved by winding magnetic tape about an obround mandrel such that the tape is stacked up along the perimeter of the mandrel to a desired thickness. For example, in the embodiment illustrated by
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
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