Patent Application
20160211713
The present disclosure relates to a generator and, in particular, to a main rotor of a generator.
Typically, a generator includes a rotor having a plurality of windings (made up of electrically conductive wires) wrapped around elongated poles on a rotor core. The rotor is driven to rotate by a source of rotation, a prime mover such as a turbine rotor. The generator rotor rotates in proximity to a stator, and the rotation of the rotor, which is an electromagnet due to electricity running through the windings, induces a voltage in the stator. The voltage in the stator can be applied to external electrical components, providing electrical power to those components. During operation, the generator rotor rotates at very high speeds, creating centrifugal forces on the poles and windings that may cause the wires of the windings on the poles to move. End winding supports at each end of the poles are used to support the windings under centrifugal load and ensure that the wires do not move from a desired position.
An end winding support for a generator rotor includes a support body with an annular inner surface configured to be radially outward from a rotor shaft, a plurality of winding support arms extending radially outward from the support body, and a plurality of orifices extending from the annular inner surface of the support body to an exterior surface of the support body adjacent the plurality of winding support arms. The plurality of orifices is configured to transfer lubricant from a surface of the rotor shaft to a plurality of windings located on the plurality of winding support arms.
A rotor for a generator includes a shaft, a rotor core radially outward from the shaft and having a plurality of poles spanning axially along the rotor core, and an end winding support radially outward from the shaft and adjacent to the rotor core. The end winding support includes a support body with an annular inner surface adjacent to the shaft, a plurality of winding support arms that extend radially outward from the support body, and a plurality of orifices extending from the annular inner surface of the support body to an exterior surface of the support body adjacent the plurality of winding support arms. The rotor also includes a plurality of windings with each winding being wrapped axially around each of the plurality of poles and a corresponding end winding support arm. The rotor is configured such that the plurality of orifices can transfer lubricant from a surface of the shaft to the plurality of windings.
An end winding support for a generator rotor is disclosed herein that includes a lubricant manifold that provides cooling lubricant, such as oil, from the interior of the rotor, and more specifically, from the rotor shaft, to an electrically conductive wire winding wrapped around a portion of the rotor. The lubricant manifold can include orifices that extend through the end winding support and allow oil or another lubricant to pass from the rotor shaft to the windings. The lubricant manifold can also include an annulus on the radially annular inner surface of the end winding support to provide a space for the lubricant to accumulate before passing through the orifices. The annulus can be a metering device to ensure that a proper amount of lubricant is being transferred through the orifices. Additionally, the end winding support can include a crowned surface on winding support arms, which are adjacent to the windings, to reduce stresses on the windings while holding the individual wires in place. The end winding support is one continuous piece that circumferentially encircles the rotor shaft and is placed onto the rotor core, with the rotor shaft protruding through the end winding support and rotor core during installation. The one-piece configuration of the end winding support is preferred on some generators to provide a more complete connection between the rotor and the end winding support and to reduce the number of pieces that can become damaged during operation. The lubricant manifold (the orifices and annulus) is integrated into the end winding support to allow for lubricant, such as oil, to be distributed to the windings without additional and cumbersome lubricant/oil distribution components.
Dynamoelectric portion 22 in the disclosed, non-limiting embodiment is a three-phase machine that includes permanent magnet generator 30, main exciter 32, and main generator 34 (the three phases) mounted along rotor shaft 36, which rotates about axis of rotation A. Permanent magnet generator 30 includes rotor assembly 30A and stator assembly 30B, main exciter 32 includes rotor assembly 32A and stator assembly 32B, and main generator 34 includes rotor assembly 34A and stator assembly 34B. Stator assemblies 30B, 32B, and 34B are installed in housing assembly 28 and do not rotate while rotor assemblies 30A, 32A, and 34A are installed on rotor shaft 36 and rotate in unison. Housing assembly 28 may be closed at one end by drive-end cover assembly 28A through which rotor shaft 36 extends and at the other end by non-drive-end cover assembly 28B through which rotor shaft 36 does not extend.
Permanent magnet generator 30, with rotor assembly 30A and stator assembly 30B, supplies power for generator excitation, as well as power for other components of an electrical system. Main exciter 32, with rotor assembly 32A and stator assembly 32B, receives field excitation from permanent magnet generator 30 through the generator power control unit (GPCU). The output of main exciter 32 is supplied to rotor mounted diode pack 37. Diode pack 37 can be divided into six diodes to provide a three-phase full wave bridge rectification. The DC current output of diode pack 37 supplies main generator 34 with electricity. Main generator 34, with rotor assembly (main rotor assembly) 34A and stator assembly (main stator assembly) 34B, outputs power to supply exterior electrical energy needs.
As discussed above, main rotor assembly 34A is radially outward from and mounted on rotor shaft 36 so that main rotor assembly 34A rotates with rotor shaft 36 (which is driven by prime mover T) about axis of rotation A. Rotor shaft 36 can have a constant diameter along the axial length of rotor shaft 36 or can have a varying diameter depending on design considerations.
Rotor core 38 is radially outward from rotor shaft 36 and is the principal structural component of main rotor assembly 34A. Rotor core 38 extends axially along rotor shaft 36 and rotates in unison with rotor shaft 36. Rotor core 38 can be made from a variety of suitable materials, including metal or another material than can handle the elevated temperatures and high centrifugal forces caused by the rotation of rotor assembly 34A.
Poles 40 are radially extending components of rotor core 38. Poles 40 run axially along the outer side of rotor core 38 and can span the entire axial length of rotor core 38. Poles 40 can be made from the same material as rotor core 38, and rotor core 38 and poles 40 can be one continuous piece. While
Wrapped around each of poles 40 are windings 42, which are each continuous wires that are electrically conductive and wrapped multiple times around pole body 40A of poles 40. The wires of windings 42 can be arranged in a single layer on poles 40 or can be multiple layers of wires. Windings 42 are each connected to diode pack 37, which provides windings 42 with DC current to cause windings 42 to become an electromagnet. When rotor shaft 36, rotor core 38, poles 40, and electromagnetic windings 42 are in operation, they rotate and induce voltage in main stator assembly 34B which is used to output electrical energy.
Pole winding supports 44 are located on each end of poles 40 and configured to hold the ends of each of windings 42 in place. Pole winding supports 44 also function to hold end winding support 46 in place. Pole winding supports 44 can be fastened to poles 40 by various means; including adhesive, bolts, rivets, latches, welds, or other fasteners; and can be made from a variety of materials, such as a material that is non-magnetic, including aluminum or plastic.
At each axial end of rotor core 38 (and poles 40) is end winding support 46, which is configured to provide end support to windings 42 to prevent the wires of windings 42 from becoming displaced due to the centrifugal forces exerted on windings 42 by the rotation of rotor shaft 36, rotor core 38, poles 40, and windings 42. End winding support 46 has an annular inner surface (shown in
End winding support 46 includes support body 48 (which includes an annular inner surface (shown in
Extending radially outward from support body 48 and supporting the ends of windings 42 are winding support arms 50. A flat back surface of winding support arms 48 (shown in
As discussed above, annular inner surface 56 of support body 48 is radially adjacent to rotor shaft 36 so that rotor shaft 36 extends through the annular opening in support body 48 around which is annular inner surface 56. Flat back surface 52 is adjacent to rotor core 38 (which is a bottom surface not viewable in either of
End winding support 46 is shown in
Flat back surface 52 of end winding support 46 (a rear surface of both support body 48 and winding support arms 50) attaches to rotor core 38 and poles 40. Winding contact surface 62 of winding support arms 50, which is opposite flat back surface 52, is in contact with windings 42 and prevents windings 42 from displacing when generator 20 is in operation. Winding contact surface 62 can be crowned to reduce the stresses on windings 42 and can include grooves 64 to prevent the individual wires of windings 42 from movement. Winding support arms 50, and support body 48, can include other grooves 54A or indents that allow cooling air or lubricant/oil to access various components of main rotor assembly 34A. Additionally, winding support arms 50 can include lip 66 on the radially outward end to aid in keeping windings 42 from moving. When rotor core 38 has a configuration that includes four poles 40, winding support arms 50 will extend radially away from support body 48 at an angle 90 degrees from adjacent winding support arms 50 so as to be axially aligned with poles 40.
Within support body 48 are orifices 58 and annulus 60 (which is on annular inner surface 56). Together, orifices 58 and annulus 60 transfer and disperse lubricant, such as oil, from the surface of rotor shaft 36 and annular inner surface 56 to windings 42. Orifices 58 are holes that extend through support body 48 from annular inner surface 56 to the radially exterior surface of support body 48 adjacent winding support arms 50. Support body 48 can include any number of orifices 58 having any orientation, with a preferred configuration that transfers lubricant to windings 42 at a rate that keeps windings 42 sufficiently cool without wasting or inefficiently using more lubricant than needed.
Annulus 60 is an annular groove on annular inner surface 56. Annulus 60 provides a gap between support body 48 and rotor shaft 36 in which a lubricant, such as oil, can accumulate and then be transferred through orifices 58 to winding support arms 50 and windings 42. The size and depth of annulus 60 is configured to meter the amount of lubricant allowed to flow through orifices 58 so that the lubricant is not used inefficiently. Additionally, the opening of orifices 58 on annular inner surface 56 can be placed in annulus 60 to allow for lubricant to flow directly from annulus 54 into orifices 58, or the opening of orifices 58 on annular inner surface 56 can be near but not in annulus 60 to allow for the lubricant to first flow along annular inner surface 56 before entering orifices 58. Annulus 60 can have a constant or varying groove depth depending on design considerations to prevent excessive lubricant. Also, annulus 60 can be a varying distance (axially) from flat back surface 52 or can be a number of annular grooves suited to meter the amount of lubricant transferred to orifices 58.
As mentioned above, winding contact surface 62 of winding support arms 50 can be crowned to reduce stresses on windings 42 while holding the individual wires in place to prevent displacement during the operation of generator 20. Additionally, end winding support 46 includes a lubricant manifold (orifices 58 and annulus 60) that provides lubricant, such as oil, to windings 42 from the interior of support body 48, and more specifically from annular inner surface 56 and rotor shaft 36. Orifices 58 transfer the lubricant/oil while annulus 60 meters the flow of lubricant to ensure that a sufficient amount of lubricant/oil is being transferred to windings 42 while preventing excessive lubricant loss. End winding support 46 is one continuous piece that circumferentially encircles rotor shaft 36 and is threaded onto rotor shaft 36 during installation. The one-piece configuration of end winding support 46 is preferred on some generators to provide a more complete connection between rotor shaft 36 and end winding support 46 and to reduce the number of pieces that can become damaged during operation. Orifices 58 and annulus 60 are integrated into support body 48 to allow for lubricant to be distributed to windings 42 without additional and cumbersome lubricant/oil distribution components, therefore reducing cost, increasing efficiency, and improving durability.
The following are non-exclusive descriptions of possible embodiments of the present invention.
An end winding support for a generator rotor includes a support body with an annular inner surface configured to be radially outward from a rotor shaft, a plurality of winding support arms extending radially outward from the support body, and a plurality of orifices extending from the annular inner surface of the support body to an exterior surface of the support body adjacent the plurality of winding support arms with the plurality of orifices configured to transfer lubricant from a surface of the rotor shaft to a plurality of windings located on the plurality of winding support arms.
The end winding support of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
At least four winding support arms extend radially outward from the support body.
At least four winding support arms extend radially outward from the support body at an angle perpendicular to the annular inner surface of the support body.
An annulus on the annular inner surface of the support body is provided for metering the amount of lubricant transferred to the plurality of windings through the plurality of orifices.
A depth of the annulus is constant.
The plurality of orifices extend from the annulus on the annular inner surface to the exterior surface of the support body.
At least two orifices of the plurality of orifices are arranged to provide a sufficient amount of lubricant to each of the plurality of windings.
At least one orifice of the plurality of orifices is angled to be non-parallel to a line perpendicular to the annular inner surface of the support body at the point where the at least one orifice intersects the annular inner surface.
A winding contact surface of each winding support arm is crowned.
The end winding support is constructed from plastic.
The plurality of orifices are equally spaced circumferentially around the support body.
Each of the plurality of orifices are angled to be perpendicular to the annular inner surface of the support body at the point where each of the plurality of orifices intersects the annular inner surface.
A rotor for a generator includes a shaft, a rotor core radially outward from the shaft and having a plurality of poles spanning axially along the rotor core, and an end winding support radially outward from the shaft and adjacent to the rotor core. The end winding support can include a support body with an annular inner surface adjacent to the shaft, a plurality of winding support arms that extend radially outward from the support body, and a plurality of orifices extending from the annular inner surface of the support body to an exterior surface of the support adjacent the plurality of winding support arms. The rotor also includes a plurality of windings with each winding being wrapped axially around each of the plurality of poles and a corresponding end winding support arm. The plurality of orifices are configured to transfer lubricant from a surface of the shaft to the plurality of windings.
The rotor of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
An annulus on the annular inner surface of the support body for metering the amount of lubricant transferred to the plurality of windings through the plurality of orifices.
A winding contact surface of each winding support arm is crowned.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
