Abstract:
A laminated stator for a motor includes a first plurality of stator laminations with a first electrical conductivity and a first thermal conductivity, and a second plurality of stator laminations with a second electrical conductivity and a second thermal conductivity, wherein the second electrical conductivity is lower than the first electrical conductivity, the second thermal conductivity is higher than the first thermal conductivity, and the second plurality of stator laminations are disposed throughout the first plurality of stator laminations.

Description:
BACKGROUND 
       [0001]    The subject matter disclosed herein relates to motors, and more particularly, to a stator for a motor with laminations to facilitate cooling. 
         [0002]    Environmental control systems can utilize electric motors to pressurize and move air for use within the cabin of an aircraft. The electric motor of the environmental control system, as well as other motors, may utilize air cooling to cool the motor during operation. Often air cooling may not provide for sufficient cooling of the motor during certain operating conditions. 
       BRIEF SUMMARY 
       [0003]    According to an embodiment, a laminated stator for a motor includes a first plurality of stator laminations with a first electrical conductivity and a first thermal conductivity, and a second plurality of stator laminations with a second electrical conductivity and a second thermal conductivity, wherein the second electrical conductivity is lower than the first electrical conductivity, the second thermal conductivity is higher than the first thermal conductivity, and the second plurality of stator laminations are disposed throughout the first plurality of stator laminations. 
         [0004]    According to an embodiment, an environmental control system cooled by an airflow includes a motor cooling inlet to receive the airflow, and a motor including a rotor, and a laminated stator to receive the airflow from the motor cooling inlet, including a first plurality of stator laminations with a first electrical conductivity and a first thermal conductivity, and a second plurality of stator laminations with a second electrical conductivity and a second thermal conductivity, wherein the second electrical conductivity is lower than the first electrical conductivity, the second thermal conductivity is higher than the first thermal conductivity, and the second plurality of stator laminations are disposed throughout the first plurality of stator laminations. 
         [0005]    Technical function of the embodiments described above includes a second plurality of stator laminations with a second electrical conductivity and a second thermal conductivity, wherein the second electrical conductivity is lower than the first electrical conductivity and the second thermal conductivity is higher than the first thermal conductivity. 
         [0006]    Other aspects, features, and techniques of the embodiments will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like elements are numbered alike in the FIGURES: 
           [0008]      FIG. 1  is a schematic view of one embodiment of an environmental control system; 
           [0009]      FIG. 2  is a schematic view of one embodiment of a motor stator for use with the environmental control system of  FIG. 1 ; and 
           [0010]      FIG. 3  is end view of the motor stator of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Referring now to the drawings,  FIG. 1  shows an environmental control system  100 . In the illustrated embodiment, the environmental control system  100  includes a motor  110  with a stator  112  and a rotor  114 . In the illustrated embodiment, the motor  110  can be utilized to drive a compressor in the environmental control system  100  to provide environmental air for the cabin of an aircraft. 
         [0012]    During operation, the motor  110  can generate heat. In the illustrated embodiment, airflow  102  can be utilized to air cool the motor  110 . In the illustrated embodiment, airflow  102  is received from the compressor inlet  106  and is directed to the motor cooling inlet  108 . The airflow  102  can flow through the motor stator  112  and exit through the cooling exit  104 . In certain embodiments, the amount of airflow  102  is limited by operating conditions, such as high speed, high altitude operating conditions, which may not provide adequate cooling of the motor  110 . In these operating conditions, conventional motors  110  may exceed target operating temperatures affecting reliability and performance. Advantageously, the stator  112  can include cooling lamination layers to increase heat transfer to remove heat from the stator  112 . 
         [0013]    In  FIG. 2 , the motor stator  112  is shown. In the illustrated embodiment, the motor stator  112  is a laminated motor stator with conductive lamination layers  120  and cooling lamination layers  122 . In certain embodiments, the motor  110  can be utilized with the environmental control system  100 , while in other embodiments, the motor  110  and the motor stator  112  described herein can be used for any suitable application. 
         [0014]    In the illustrated embodiment, the conductive lamination layers  120  and the cooling lamination layers  122  are stacked to form the motor stator  112 . The conductive lamination layers  120  and the cooling lamination layers  122  can be bonded together to form the laminated stator  112 . 
         [0015]    In the illustrated embodiment, the conductive lamination layers  120  allow for normal electromagnetic operation of the motor stator  112 . In the illustrated embodiment, a plurality of conductive lamination layers  120  can be layered or stacked to form the stator  112 . Generally, the conductive lamination layers  120  have a high electrical conductivity and a relatively low thermal conductivity relative to the cooling lamination layers  122 . In the illustrated embodiment, the conductive lamination layers  120  can be electrical steel, such as Arnon, or other suitable materials for forming a motor stator  112 . During operation, the conductive lamination layers  120  can generate heat due to the electrical energy passing through the conductive lamination layers. In the illustrated embodiment, the conductive lamination layers  120  may conduct some heat to be removed by the airflow  102 , however during typical operation the use of the conductive lamination layers  120  introduces additional heat into the stator  112 . 
         [0016]    In the illustrated embodiment, the cooling lamination layers  122  can transfer and dissipate heat generated by the motor stator  112 , and in particular the heat generated by the conductive lamination layers  120 . In the illustrated embodiment, the cooling lamination layers  122  can be formed from annealed pyrolytic graphite. Advantageously, annealed pyrolytic graphite has a relatively high thermal conductivity (1700 W/m-K). Further, annealed pyrolytic graphite can provide generally anisotropic heat transfer. In other embodiments, the cooling lamination layers  122  can be formed from any suitable material with a low electrical conductivity and a high thermal conductivity relative to the conductive lamination layers  120 . The heat generated by the conductive lamination layers  120  can be dissipated and moved out to the fins  124 ,  126  (as shown in  FIG. 3 ) or otherwise to the edges or outermost surfaces of the cooling lamination layers  122  to facilitate heat transfer with the airflow  102 . In the illustrated embodiment, it is desired for the cooling lamination layers  122  have a low electrical conductivity compared to the conductive lamination layers  120  to prevent from the cooling lamination layers  122  from introducing heat into the stator  112 . Therefore, in certain embodiments, a greater amount of heat is removed from the cooling lamination layers  122  than is generated by the cooling lamination layers  122 , allowing for effective cooling of the stator  112 . 
         [0017]      FIG. 3  shows an end view of the stator  112  illustrating a lamination shape  123 . In certain embodiments, both the conductive lamination layers  120  and the cooling lamination layers  122  can have the lamination shape  123  shown. In the illustrated embodiment, a cooling lamination layer  122  is shown the with the lamination shape  123 . In certain embodiments, the lamination shape  123  can have any suitable shape. In the illustrated embodiment, the lamination shape  123  can include inner motor teeth  126  and outer fins  124  to facilitate cooling of the stator  112 . The inner motor teeth  126  can conduct heat towards the outer fins  124 , and the outer fins  124  can increase surface area of both the conductive lamination layers  120  and the cooling lamination layers  122 . 
         [0018]    In the illustrated embodiment, the conductive lamination layers  120  and the cooling lamination layers  122  can have the same lamination shape  123 . Advantageously, since the conductive lamination layers  120  and the cooling lamination layers  122  have the same lamination shape  123  ease of processing and assembly can be facilitated. After assembly, the conductive lamination layers  120  and the cooling lamination layers  122  can be glued and or bonded to form the stator  112 . 
         [0019]    In certain embodiments, the ratio of conductive lamination layers  120  to cooling lamination layers  122  can be twenty conductive lamination layers  120  to one cooling lamination layer  122 . Based on a twenty to one ratio of conductive lamination layer  120  and the cooling lamination layer  122 , this results in equivalent radial direction thermal conductivity of 113.2 W/m-K. In other embodiments, the ratio can be any suitable ratio to allow for suitable electrical and thermal performance of the stator  112 . In certain embodiments, the thickness of each of the conductive lamination layers  120  and the cooling lamination layers  122  can be selected for desired thermal and electrical characteristics. In the illustrated embodiment, the length of the stator  112  is affected by the number of cooling lamination layers  122  in the stator  112 . The introduction of cooling lamination layers  122  may lengthen the stator  112 . 
         [0020]    In the illustrated embodiment, the introduction of cooling lamination layers  122  allows for more effective cooling of motors  110  utilizing air cooling from an airflow  102 . In certain embodiments, such as a motor  110  for use in an environmental control system  100 , operating temperatures have been reduced from 236.9 C to 211 C, for worst case cooling and electrical load conditions, allowing for greater reliability of the motor  110 . 
         [0021]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. While the description of the present embodiments has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications, variations, alterations, substitutions or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the embodiments. Additionally, while various embodiments have been described, it is to be understood that aspects may include only some of the described embodiments. Accordingly, the embodiments are not to be seen as limited by the foregoing description, but are only limited by the scope of the appended claims.