Claims:We claim,

1. A rotor end plate (100) for an electric motor, said rotor end plate (100) comprising:
a plurality of cooling fins (102) adapted to churn air to stator end windings(10W) to facilitate cooling of the stator end windings (10W) during operation of the electric motor.

2. The rotor end plate (100) as claimed in claim 1, wherein said cooling fins (102) are adapted to facilitate weight balancing of a rotor assembly (20) of the electric motor.

3. The rotor end plate (100) as claimed in claim 2, wherein a bottom portion of at least one of said cooling fin (102) is adapted to facilitate weight removal during balancing of the rotor assembly (20).

4. The rotor end plate (100) as claimed in claim 3 is configured to be provided in at least an interior permanent magnet rotor assembly (20) of the electric motor.

5. A method (200) for cooling stator end windings (10W) in an electric motor, said method (200) comprising:
providing a rotor end plate (100) with a plurality of cooling fins (102);
churning air to stator end windings (10W) through the cooling fins (102) to facilitate cooling of the stator end windings (10W) during operation of the electric motor; and
venting the hot air from the electric motor by providing a plurality of air vents on a stator housing.

6. The method (200) as claimed in claim 5 comprising, balancing a rotor assembly (20) of the electric motor by at least one of weight addition and weight removal with respect to the cooling fins (102) of the rotor end plate (100).

7. The method (200) as claimed in claim 5, wherein the electric motor is at least an interior permanent magnet motor.
, Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to electric motors and more particularly, to a rotor end plate and a method for cooling stator end windings in an electric motor.

BACKGROUND
[002] Interior permanent magnet (hereinafter IPM) motor is a type of motor which uses high energy magnets such as rare earth based magnets. Usually, heat is generated in stator windings of IPM motor, which in turn would decrease the performance of the IPM motor due to densely packed stator operating at a high performance level. Therefore, cooling of stator end windings is required to dissipate the heat generated in the stator end windings. A Conventional IPM motor includes a fan which provides air to the stator windings to cool the stator end windings. However, providing fan in the IPM motor is complex and difficult when the electric motor needs to be sealed from the outside environment. Another conventional motor includes a stator housing provided with water jackets having fluid passages through which a cooling liquid, such as water, may be circulated to remove heat from the stator windings to cool the stator end winding. However, providing water jackets in stator housing of the electric motor incurs added cost and is complex in design. Another conventional motor include spraying devices which directs oil or other coolant directly onto end turns of a stator. However, providing spraying devices in electric motors incur added cost and packaging and arrangement of the spraying devices adds complexity to the design of the electric motors.
[003] Other conventional systems and methods for cooling stator end windings in electric motors would require a design change in the electric motor thereby making the design complex and may lead to difficulties in packaging and arrangement of the components present in the electric motor and incurs high cost
[004] Therefore, there exists a need for a rotor end plate and a method for cooling stator end windings in an electric motor, which obviates the aforementioned drawbacks.

OBJECTS

[005] The principal object of an embodiment herein is to provide a rotor end plate for an electric motor, which has cooling fins for cooling stator end windings in the electric motor and also to facilitate rotor weight balancing by at least one of weight addition and weight removal thereof.
[006] Another object of an embodiment herein is to provide a method for cooling stator end windings in an electric motor.
[007] Another object of an embodiment herein is to provide a rotor end plate for an electric motor, which improves performance of the electric motor.

[008] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[009] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0010] Fig. 1 depicts a cross-sectional view of a stator assembly and a rotor assembly of an interior permanent magnet motor in assembled condition, according to an embodiment as disclosed herein;
[0011] Fig. 2 depicts a perspective view of the rotor assembly, according to the embodiment as disclosed herein;
[0012] Fig. 3 depicts a perspective view of a rotor end plate of the rotor assembly, according to the embodiment as disclosed herein; and
[0013] Fig. 4 depicts a flowchart showing the steps of a method for cooling stator end windings in an electric motor, according to an embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0014] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0015] The embodiments herein achieve a rotor end plate for an electric motor, which has cooling fins for cooling stator end windings in the electric motor and also to facilitate rotor weight balancing by at least one of weight addition and weight removal thereof. Further, embodiments herein achieve a method for cooling stator end windings in an electric motor. Referring now to the drawings, and more particularly to Figs. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0016] Fig. 1 depicts a cross-sectional view of a stator assembly (10) and a rotor assembly (20) of an interior permanent magnet motor in assembled condition, according to an embodiment as disclosed herein. The electric motor includes a stator assembly (10), a rotor assembly (20) and may include other standard components as present in standard electric motor. The stator assembly (10) includes a stator housing (not shown), a stator stack (not shown), stator windings (not shown) and may include other standard components as present in a standard stator assembly. Fig. 2 depicts a perspective view of the rotor assembly (20) of an interior permanent magnet motor, according to an embodiment as disclosed herein. The rotor assembly (20) includes a rotor stack (not shown), a shaft (not shown) and a plurality of rotor end plates (100).
[0017] Fig. 3 depicts a perspective view of a rotor end plate (100), according to the embodiment as disclosed herein. In an embodiment, the rotor end plate (100) includes a plurality of cooling fins (102) adapted to churn air to stator end windings (10W) to facilitate cooling of stator end windings (10W) during operation of the electric motor. The cooling fins (102) are adapted to facilitate weight balancing of the rotor assembly (20) of the electric motor. For example, the bottom portion of each cooling fin (102) is adapted to facilitate weight removal during balancing of the rotor assembly (20). For the purpose of this description and ease of understanding, the rotor end plate (100) is configured to be provided in at least an interior permanent magnet rotor assembly (20) of the electric motor. However, it is also within the scope of the embodiment herein to provide the rotor end plate (100) in any other type of electric motors, generators or any other type of electric machines without otherwise deterring the intended function of the rotor end plate (100) as can be deduced from the description and corresponding drawings.
[0018] Fig. 3 depicts a flowchart showing the steps of a method (200) for cooling stator end windings (10W) in an electric motor, according to an embodiment of the invention as disclosed herein. For the purpose of this description and ease of understanding, the method (200) for cooling stator end windings (10W) of the electric motor is explained herein with reference to an interior permanent magnet motor. It is also within the scope of the invention to practice/implement the entire steps of the method (200) or with omission of at least one step of the method (200) or with any addition of at least one step to the method (200) for cooling stator end windings in any other type of electric motors, generators, or any other type of electric machines. In an embodiment, the method (200) comprises, providing a rotor end plate (100) with a plurality of cooling fins (102), churning air to stator end windings (10W) through the cooling fins (102) to facilitate cooling of the stator end windings (10W) during operation of the electric motor and venting the hot air from the electric motor by providing a plurality of air vents on a stator housing. Further, the method (200) comprises, balancing a rotor assembly (20) of the electric motor by at least one of weight addition and weight removal with respect to the cooling fins (102) of the rotor end plate (100).
[0019] Therefore, a rotor end plate (100) for cooling stator end winding (10W) in an electric motor is provided. Further, a method (200) for cooling stator end winding (10W) in an electric motor is provided.
[0020] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.