End winding arrangement for an electro-mechanical device

An end winding arrangement of a stator of an electro-mechanical device is provided. The end winding arrangement includes at least two stator bars, wherein each stator bar has a linear member and a cell bend member. Each of the at least two stator bars is configured to have a unitary involute member extending from each cell bend member such that the involute member is configured as a single involute section without a lead bend section for reducing vibrations in the electro-mechanical device.

The present patent document claims the benefit of European Patent Application No. EP 18180187.9, filed Jun. 27, 2018, which is also hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to an end winding arrangement of a stator of an electro-mechanical device, having at least two stator bars, each stator bar including a linear member, an involute member, and a cell bend member.

BACKGROUND

Certain electro-mechanical devices are known to a person skilled in the art. Such a commonly known electro-mechanical device is, for example, an electric generator.

An electric generator may include a stator and a rotor disposed within the stator.FIG. 1illustrates an end winding arrangement101, in accordance to the state of the art, of a stator of an electric generator. The end winding arrangement101has a plurality of stator bars201interconnected by conductors106. Each of the stator bars201accommodates therewithin a conductor106. Each stator bar201has a linear member103, an involute member104, and a cell bend member105.FIG. 2illustrates a stator bar102, in accordance to the state of the art, of the end winding arrangement101illustrated inFIG. 1. The linear member103and the involute member104are attached via the cell bend member105. The involute member104has an involute section104A extending from the cell bend member105, and a lead bend section104B extending from the involute section104A. The conductor106extends out of the lead bend section104B. The lead bend section104B is disposed angularly with respect to the involute section104A to provide ease of connection of the conductors106accommodated therewithin. The end winding arrangements101, in electric generators, may be required for coil connections via these conductors106. A large amount of material such as copper is spent for construction of these end winding arrangements101. Moreover, length of the involute members104of the stator bars102, make the stator and in turn the generator longer and bulkier in size thereby, introducing vibration issues during operation of the electric generator which leads to dusting, strand breakage, etc. Furthermore, higher rewound time is required as a large quantity of auxiliary connection elements such as diamond spacers and end blocks are required for longer involute members104. Furthermore, longer length of the involute members104poses design challenges in terms of not meeting electrical strikes with stator frame and creates many design complexities and manufacturing complexities due to bending of the stator bars201. Additionally, longer length of the involute members104requires complex arrangement for mechanical support of the stator thereby increasing costs associated therewith.

SUMMARY AND DESCRIPTION

Therefore, it is an object of the present disclosure to provide an end winding arrangement of a stator of an electro-mechanical device of the aforementioned kind, having at least two stator bars each including at least a linear member, a cell bend member, and an involute member, that reduces size of the electro-mechanical device and costs associated therewith, without compromising operational efficiency of the electro-mechanical device.

The end winding arrangement achieves the aforementioned object, in that each of the at least two stator bars is configured to have a unitary involute member, that is a single involute member without any lead bends, extending from the cell bend member such that an overall length of the stator bar is reduced.

In accordance with the present disclosure, an end winding arrangement of a stator of an electro-mechanical device, having at least two stator bars each including at least a linear member, an involute member, and a cell bend member is provided. While the disclosure has been described with reference to various parts of the stator bar addressed using words such as a linear member, an involute member, and a cell bend member, it is understood that a stator bar is configured as a single piece of material and that these words, which have been used herein and after, are merely words of description to identify and illustrate various parts of the stator bar, rather than words of limitation and are in no way to be construed as limiting of the present disclosure herein.

In accordance with the present disclosure, each stator bar of the at least two stator bars is configured to have a unitary involute member extending from the cell bend member. The unitary involute member refers to a single involute section extending from the cell bend member, for example, a member having a gradual change in its slope along its length, without a drastic change of slope such as a near orthogonal bend. Advantageously, the involute member is configured without a lead bend section as disclosed inFIG. 2. The involute member is configured of a developed length of about 15% to about 60% of a developed length of the stator bar. Elimination of the lead bend section results in a reduction in an overall developed length of the stator bar of about 3% to about 6%. The involute member is disposed angularly with respect to a linear member of the stator bar and is attached to the linear member via the cell bend member. The involute member is cantilevered at the cell bend member such that a free end of the involute member provides an opening for conductors to extend through, for connection with conductors accommodated inside other involute members of other stator bars.

The end winding arrangement disclosed herein includes a connector member configured to interconnect the conductor accommodated inside each of the two stator bars. Due to elimination of the lead bend section, the conductors extending out of the involute member are disposed angularly with respect to the linear member. In an embodiment, the conductors extending out of the involute member are aligned with respect to the geospatial positioning, for example, an inclination, of the involute member. In another embodiment, the conductors extending out of the involute member are configured according to connection requirements, for example, the conductors of the at least two stator bars are bent towards each other in order to be fastened by a fastener.

In order to interconnect each of the conductors, the connector member is configured to have a twisted and/or a non-twisted configuration. The twisted configuration includes, for example, a configuration wherein two or more parts of the connector member have their planes angularly disposed with respect to one another. Connector members with twisted configurations include, for example, a bent clip connector member, a curved clamp connector member, etc. Advantageously, the twisted-configuration connector members avoid requirement to bend the conductors thereby, reducing complexities involved in the assembly of the end winding arrangement. The non-twisted configuration includes, for example, a configuration wherein the parts of the connector member majorly lie in a single plane. Connector members with non-twisted configurations include, for example, a nut-bolt connector member, a pin connector member, a linear clamp connector member, etc. The connector member configuration is selected based on the conductor being connected, (e.g., a shape, a configuration, etc., of the conductor being connected). In an embodiment, when the conductor extending through the involute member is having a rectangular shaped flat end extending at an axial inclination nearly same as an axial inclination of the involute member, a twisted configuration of the connector member is selected for interconnection of the conductors. In another embodiment, when the conductor extending through the involute member is of a configuration including, for example, a conductor with a bent end, a conductor with a curved end, a conductor with a protruding end, etc., a non-twisted configuration of the connector member is selected.

Also disclosed herein is a stator for an electro-mechanical device having a frame, a stator core attached to the frame, and the aforementioned end winding arrangement having at least two stator bars each having at least a linear member and a cell bend member, wherein each of the stator bars is configured to have a unitary involute member extending from the cell bend member.

Also disclosed herein is an electro-mechanical device having a rotor and a stator including the aforementioned end winding arrangement having at least two stator bars each having at least a linear member and a cell bend member, wherein each of the stator bars is configured to have a unitary involute member extending from the cell bend member. The electromechanical device is an electric generator or an electric motor.

DETAILED DESCRIPTION

Various embodiments are described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for the purpose of explanation, numerous specific details are set forth in order to provide thorough understanding of one or more embodiments. It may be evident that such embodiments may be practiced without these specific details.

FIG. 3illustrates a stator bar201of an end winding arrangement of a stator of an electric generator. The stator bar201includes a linear member103, a cell bend member105, and an involute member301. A conductor106is accommodated within the stator bar201and extends from within the linear member103and out of a free end301A of the involute member301. The involute member301A and a top part106A of the conductor106extending through the involute member301, are aligned with respect to each other as shown in theFIG. 3.

FIG. 4Aillustrates an end winding arrangement300having stator bars201illustrated inFIG. 3. The end winding arrangement300includes multiple stator bars201each having a linear member103, an involute member301, and a cell bend member105.FIG. 4Billustrates an enlarged view of a portion of the end winding arrangement300marked “A” inFIG. 4Ashowing connector members302. Each of the connector members302connects the conductors106accommodated inside the stator bars201and extending out of the involute members301. As shown inFIG. 4B, the connector members302are of a twisted configuration in form of a twisted clip structure for connecting conductors106. Parts302A and302B of the twisted clip structures each accommodate conductors106there within for forming a connection there between.

FIGS. 5A-5Cillustrate various embodiments of a connector member302used for interconnecting conductors106accommodated within the involute members301of the end winding arrangement300illustrated inFIG. 4A.FIG. 5Aillustrates a connector member302of a non-twisted configuration in form of a pair of linear plates302C and302D clamped together via one or more fasteners302E to form a connection between the conductors106. The conductors106are configured to have protrusions106B in form of spherical connections, that are fastened between the linear plates302C and302D with help of fasteners302E.FIG. 5Billustrates a connector member302of yet another non-twisted configuration in form of a flat bar, for interconnection the conductors106. The conductors106are configured with bent ends106C that are connected via the connector members302.FIG. 5Cillustrates a connector member302of yet another non-twisted configuration in form of a fastener302E such as a nut-bolt arrangement for fastening the conductors106. The conductors106are configured to form joints there between, for example, with curved ends106D to form a lap joint or a bolted joint by having mutually cavities overlapping for accommodating the fastener302E.

FIG. 6illustrates a sectional view of an active part of an electric generator600having a rotor602and a stator601with the end winding arrangement300. As illustrated inFIG. 6, the stator601includes a frame601A, a stator core601B partially surrounding the rotor602, and stator bars201. The stator bars201are rigidly attached to the stator core601B. The end winding arrangement300shown inFIG. 6is as disclosed in the detailed description ofFIGS. 3-5C.

The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present disclosure. While the disclosure has been described with reference to various embodiments, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Further, although the disclosure has been described herein with reference to particular means, materials, and embodiments, the disclosure is not intended to be limited to the particulars disclosed herein; rather, the disclosure extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may affect numerous modifications thereto and changes may be made without departing from the scope and spirit of the disclosure in its aspects.