Abstract:
The invention relates to an electric appliance ( 1 ) which comprises a machine module ( 2 ) provided with an electric machine ( 3 ) comprising a stator ( 4 ) and a rotor. A machine housing ( 7 ) of the machine module ( 2 ) receives the electric machine ( 3 ). A cooling module ( 19 ) comprises a cooling housing ( 21 ), which is fluidically connected to the machine housing ( 7 ) by means of a first cooling fluid connection area ( 20 ) in a housing wall ( 17 ) of the machine housing ( 7 ) and to at least one second cooling fluid connection area ( 23 ) in the housing wall ( 17 ) of the machine housing ( 7 ). The inside of the machine housing ( 7 ) can be fluidically connected to the inside of the cooling housing ( 21 ) in one section of the housing wall ( 17 ), which is oriented towards the cooling housing ( 21 ), by means of at least one third cooling fluid connection area ( 25 ) comprising at least one cooling fluid through-opening ( 26 ). Various cooling module variants can use said third cooling fluid connection area ( 25 ) when other cooling module variants, which can be used in exchange with the cooling module ( 19 ) in the machine module ( 2 ), do not use the third cooling fluid connection area ( 25 ). As a result, an electric appliance ( 1 ), a machine module ( 2 ) therefore and a set comprising a plurality of different cooling modules, which can meet altered cooling requirements having reduced structural and constructural costs, can be produced.

Description:
BACKGROUND OF THE INVENTION 
   An electrical appliance having a machine module and a cooler module, a machine module for an electrical appliance such as this, as well as a set comprising a plurality of cooler modules for assembly with a machine module such as this. 
   The invention relates to an electrical appliance. The invention also relates to a machine module for an electrical appliance and to a set comprising a plurality of cooler modules for assembly with a machine module. 
   An electrical appliance of the type mentioned initially is known from JP 60-219 939 A. There, the electrical appliance has a heat exchanger through which a flow passes along a zigzag path, starting from the first cooling fluid connection zone, to the second cooling fluid connection zone. The cooling of known electrical appliances such as these is in each case matched to the machine module that is used. As soon as it is found that a specific cooling technique is no longer adequate for the machine module, the cooling for the electrical appliance must be completely redesigned. 
   One object of the present invention is therefore to refine an electrical appliance of the type mentioned initially in such a manner that it is possible to satisfy changing cooling requirements with less construction and design effort. 
   According to the invention, this object is achieved by an electrical appliance having a) a machine module which includes an electrical machine with a stator and a rotor, a machine housing, which holds the electrical machine, and b) a cooler module, including a cooler housing which is connected for fluid flow purposes via a first cooling fluid connection zone in a housing wall of the machine housing, and at least one second cooling fluid connection zone in the housing wall of the machine housing to the interior of the machine housing, wherein the interior of the machine housing can be connected for fluid flow purposes, in a section of the housing wall which faces the cooler housing, via at least one third cooling fluid connection zone by means of at least one cooling fluid aperture opening to the interior of the cooler housing. 
   According to the invention, it has been found that different variants of the cooling air guidance in the machine housing can be provided by the specific configuration of the machine housing of the machine module with three cooling fluid connection zones. These different cooling air guidance variants can then be combined with appropriate cooler modules, so that it is possible to take account of individual cooling requirements. The electrical appliance according to the invention can thus be equipped with different cooling techniques for the respective cooler module, without any need to make any physical changes for this purpose to the machine module, in particular without having to make any physical changes to the machine housing. By way of example, the following cooling techniques can be implemented with the same machine housing, just by adaptation of the cooler module: open air cooling from both ends of the electrical machine, closed air cooling with an air-air heat exchanger from both ends of the electrical machine, closed air cooling with an air-water heat exchanger from both ends of the electrical machine, open air cooling flowing longitudinally through the electrical machine, closed air cooling flowing longitudinally through the electrical machine with an air-air heat exchanger, closed air cooling flowing longitudinally through the electrical machine with an air-water heat exchanger. The cooler module either has only the function of cooling fluid guidance or includes active cooling elements such as heat exchangers. A standardized machine housing can be used for all of these cooling techniques. An electric motor, or alternatively a generator, may be used as the electrical machine. 
   SUMMARY OF THE INVENTION 
   According to another feature of the present invention, a machine housing can hold the electrical machine in such a manner that an axial cooling fluid flow is produced between a stator casing and the housing wall. This provides effective stator cooling. 
   According to another feature of the present invention, a machine housing can hold the electrical machine in such a manner that a cooling fluid flow which surrounds the stator casing is provided between the stator casing and the housing wall. This allows cooling fluid guidance in which cooling fluid is not only supplied to or carried away from the ends of the machine, but is also passed via a central section of the machine housing. The cooling fluid can be supplied to this central section of the machine housing via the circulating and tangential cooling fluid flow component. This allows on the one hand cooling from both ends, and as well as cooling which flows through the machine from one end, on the other hand to be provided with one and the same machine housing. 
   According to another feature of the present invention, the housing wall can have webs which run internally parallel to the stator axis, on which webs the stator casing rests at least in places, and which webs release aperture openings for circulating cooling fluid flow when the stator is fitted. Webs offer a simple design capability to ensure a circulating cooling fluid flow. 
   According to another feature of the present invention, through openings, called hereinafter aperture openings, can be provided in the webs to result in defined tangential cooling fluid guidance. 
   According to another feature of the present invention, air can be used as the cooling fluid. This represents the simplest variant for cooling within the machine housing. Alternatively, it is also possible to use a different cooling fluid, in particular a cooling gas other than air. In principle, it is also possible to use a cooling liquid. 
   According to another feature of the present invention, at least one axial or radial fan can be provided in the cooler housing and/or in the machine housing in order to preset an air flow direction. This is advantageous when the rotor movement itself does not preset or does not adequately preset the desired flow direction of the cooling fluid. 
   A further object of the invention is to provide a machine module which can be connected to cooler modules which use different cooling techniques without any additional complexity. According to the invention, this object is achieved by a machine module as set forth above. 
   The advantages of this machine module correspond to those which have already been described above with reference to the electrical appliance according to the invention. 
   A further object of the invention is to provide a choice of cooling variants matched to the particular application, for a machine module, without having to make any design changes to the machine module for this purpose. 
   According to the invention, this object is achieved by a set comprising a plurality of cooler modules, for assembly with a machine module with a machine housing as set forth above, and with at least two cooler modules, comprising the following cooler module variants: 
   A first cooler module variant has a first cooler housing area which is connected for fluid flow purposes via at least one inlet opening to the surrounding area, and is connected for fluid flow purposes via corresponding aperture openings to the first and to the second cooling fluid connection zone, and a second cooler housing area which is separated in a fluid-tight manner from the first cooler housing area, and is connected for fluid flow purposes via at least one aperture opening to the third cooling fluid connection zone, and is connected for fluid flow purposes via an outlet opening to the surrounding area.
 
A second cooler module variant has a first cooler housing section which is connected for fluid flow purposes via corresponding aperture openings to the first and to the second cooling fluid connection zone, a second cooler housing section which is connected for fluid flow purposes to the first cooler housing section and is connected for fluid flow purposes via at least one aperture opening to the third cooling fluid connection zone, and a heat exchanger, which makes thermal contact with the two cooler housing sections.
 
A third cooler module variant has a first cooler housing area which is connected for fluid flow purposes via at least one inlet opening to the surrounding area, and is connected for fluid flow purposes via at least one aperture opening to the first cooling fluid connection zone, a second cooling housing area which is separated in a fluid-tight manner from the first cooling housing area and is connected for fluid flow purposes via at least one aperture opening to the second cooling fluid connection zone, and is connected for fluid flow purposes via at least one outlet opening to the surrounding area, a sealing device which seals the third cooling fluid connection zone such that no cooling fluid is exchanged between the machine module and the cooler module.
 
A fourth cooler module variant has a first cooler housing area which is connected for fluid flow purposes via at least one aperture opening to the first cooling fluid connection zone, a second cooler housing section which is connected for fluid flow purposes to the first cooler housing section and is connected for fluid flow purposes via at least one aperture opening to the second cooling fluid connection zone, a heat exchanger which makes thermal contact with the two cooler housing sections, a sealing device, which seals the third cooling fluid connection zone such that no cooling fluid is exchanged between the machine module and the cooler module through the third cooling fluid connection zone.
 
   The first cooler module variant allows open air cooling from both ends of the electrical machine. The second cooler module variant allows closed air cooling with a heat exchanger from both ends of the electrical machine. The third cooler module variant allows open air cooling flowing longitudinally through the electrical machine. The fourth cooler module variant allows closed air cooling flowing longitudinally through the electrical machine, with a heat exchanger. Depending on the ingress protection class of the electrical machine, it is then possible, for example to choose an open or closed type of cooling. A closed electrical machine can be operated with an air-air heat exchanger or with an air-water heat exchanger. The maximum cooling power based on VDE 0530 and thus the maximum machine power are achieved with an open machine with forced-draft ventilation and with air-water cooling. With a correspondingly reduced power, an air-air cooled machine offers the advantage of a closed type in combination with air cooling. Electrical machines are manufactured with different numbers of poles and are therefore designed for different rotation speeds. These machines can then the operated with a power supply system with a fixed rotation speed or from a converter with a variable rotation speed. Depending on the number of pole pairs and when converters are used for operation, it may also be advantageous, depending on the desired rotation-speed range, to cool the machine with the air flow from both ends, or from one end. In this case, the air resistance of the cooler module also plays an important role. Depending on the cooling type and number of pole pairs and the rotation speed it is possible according to the invention to choose the most efficient cooling variant with one and the same machine housing. Cooler modules with cooling air guides which do not require the third cooling fluid connection zone for the machine housing, seal them simply with the respective sealing device, so that the cooling air flows solely through the two remaining cooling fluid connection zones to the machine housing. 
   According to another feature of the present invention, at least one cooler module of the second and fourth cooler module variant can in each case be provided, with the cooler housing of the fourth cooler module variant being identical to the cooler housing of the second cooler module variant, apart from the additional sealing device. This refinement of cooler module variants is particularly advantageous for cost-effective production of these cooler module variants. Alternatively it is possible to provide a tube connection in order to supply cooling air to the machine housing. When air is supplied at one end, that is to say it flows longitudinally through the electrical machine, the third cooling fluid connection zone is closed with the aid of the sealing device. In the case of air cooling from both ends, the air is supplied via tube connections to the first and second cooling fluid connection zone, and the air is carried away via the tube connection to the third cooling fluid connection zone. 
   According to another feature of the present invention, the heat exchanger for the second or fourth cooler module variant can be a gas-gas heat exchanger, in particular an air-air heat exchanger. The heat exchanger for the second or fourth cooler module variant can also be a gas-liquid heat exchanger, in particular an air-water heat exchanger. Heat exchangers are adequate for many cooling requirements, even relatively demanding cooling requirements. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Exemplary embodiments of the invention will be explained in more detail in the following text with reference to the drawing, in which: 
       FIG. 1  shows a perspective view of a detail of an electrical appliance having a machine module and a first cooler module variant, which represents part of a set comprising a plurality of cooler modules for assembly with the machine module; 
       FIG. 2  shows a perspective view of a detail of a further electrical appliance having the machine module as shown in  FIG. 1  and of a second cooler module variant of the cooler module set, which has an air-air heat exchanger; 
       FIGS. 3-6  show perspective views of a detail of the machine module as shown in  FIG. 1 , with further cooler module variants, and 
       FIG. 7  shows a perspective, enlarged view, of a detail of a machine housing for the machine module. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  shows a perspective view of a detail of a drive appliance  1  as an example of an electrical appliance. This is a machine with a cooling circuit. The electrical appliance  1  has a motor module  2  illustrated at the bottom of  FIG. 1 , as an example of a machine module. This has an electric motor  3  as an example of an electrical machine of which only a stator  4  to be precise the right-hand cutaway half of it, is illustrated in  FIG. 1 . The stator  4  is in the form of a laminated core. As is known per se, the stator  4  has a plurality of aperture openings  5  through which fluid can flow radially through the stator  4 . The rotor, which is not illustrated, also has corresponding aperture openings, which are known per se. Furthermore both the stator  4  and the rotor have passages  6  which run both through the stator  4  and through the rotor in the axial direction and through which fluid can likewise flow. 
   The electric motor  3  is accommodated in a machine or motor housing  7 . The drawing shows only a vertically longitudinally sectioned rear half of this housing. The machine housing  7  has a first end wall  8 , on the left in the drawing, and a second end wall  9  on the right in the drawing. Adjacent to the first end wall  8  and at a distance from it, the machine housing  7  has a first intermediate wall  10 , in the left in the drawing. Adjacent to the second end wall  9 , the machine housing  7  has a second intermediate wall  11 , on the right in  FIG. 7 . When the electric motor is assembled, an end shield which is not illustrated, in each case seals the electric motor  3  from the end walls  8 ,  9 , such that it is not possible for any fluid to flow into or out of the machine housing  7  at the end, that is to say at the two ends of the electric motor  3 . When the electric motor  3  is assembled, a casing wall  12  of the stator  4  also rests on the intermediate walls  10 ,  11 . The stator casing is sealed on the housing walls via guide walls, which are not illustrated. When the electric motor  3  is assembled, the machine housing  7  is thus subdivided into an axial central section  13  between the two intermediate walls  10 ,  11  into a first edge section  14  which is shown on the left in the drawing between the first end wall  8  and the first intermediate wall  10 , and into a second edge section  15  which is shown on the right in  FIG. 7  between the second intermediate wall  11  and the second end wall  9 . 
   In the area of the central section  13 , the machine housing  7  has an octagonal cross section at right angles to its longitudinal axis. In the central section  13 , the casing wall  12  of the stator  4  rests on the machine housing  7  via webs  16  which run axially between the intermediate walls  10 ,  11  and are firmly connected to a housing casing wall  17  of the machine housing  7 . The external circumference of the stator  4  is fixed to the webs  16 . The webs  16  have fluid aperture openings  18  at right angles to their extent direction and parallel to the adjacent section of the housing wall  17 . In the illustrated exemplary embodiment, six aperture openings  18  are provided for each web  16 . 
   In  FIG. 1 , a cooler module  19  of the electrical appliance  1  is arranged above the machine housing  7  and is firmly connected to the machine module  2 . The interior of a cooler housing  21  of the cooler module  19  is connected for fluid flow purposes to the first edge section  14  of the machine housing  7  via a first cooling fluid connection zone  20  in an upper section in the drawing, of the housing wall  17  which faces the cooler module  19  and is formed at the cooler end by a cooling fluid supply opening. For this purpose, the cooler housing  21  has an aperture opening  22  in the bottom face in  FIG. 1 , which is aligned with the first cooling fluid connection zone  20  of the machine housing  7 . Furthermore, the machine housing  7  has a second cooling connection zone  23 , which is likewise formed on the motor side by a cooling fluid aperture opening in that housing wall section of the machine housing  7  which faces the cooler module  19 . The second edge section  15  of the machine housing  7  is connected for fluid flow purposes to the cooler housing  21  via the second cooling fluid connection zone  23 . For this purpose, the cooler housing  21  has a further aperture opening  24 , on the bottom face on the right in  FIG. 1 . Furthermore, the machine housing  7  has a third cooling fluid connection zone  25  in the housing wall section which faces the cooler module  19 . This is located between the first two cooling fluid connection zones  20 ,  23 . The third cooling fluid connection zone is formed on the motor side in the upper wall section in the drawing, that is to say the wall section facing the cooler housing  21 , of the central section  13  which has an octagonal cross section, of the machine housing  7  and is subdivided into a plurality, in the illustrated exemplary embodiment into a total of 18, square aperture openings  26  arranged in a grid. 
   The central section  13  is connected for fluid flow purposes to the interior of the cooler housing  21  via the third cooling fluid connection zone  25 . For this purpose, on the bottom face, the cooler housing  21  has a central aperture opening  27  between the aperture openings  22  and  24 . 
   The interior of the cooler housing  21  is subdivided into a first cooler housing area  28 , that is to say the upper cooling housing area in  FIG. 1  and into a second cooler housing area  29  which is illustrated centrally at the bottom in  FIG. 1 . The two cooling housing areas  28 ,  29  are separated from one another in a fluid-tight manner by a partition wall  30  in the form of a platform. The latter extends from a bottom intermediate web of the cooler housing  21  which is arranged between the aperture openings  22  and  27 , to a further bottom intermediate web of the cooler housing  21  between the aperture openings  27  and  24 . The first cooler housing area  28  is connected for fluid flow purposes on the one hand by the aperture openings  22  and  24  to the first cooling fluid connection zone  20 , and on the other hand to the second cooling fluid connection zone  23 . The second cooler housing area  29  is connected for fluid flow purposes via the aperture opening  27  to the third cooling fluid connection zone  25 . The first cooler housing area  28  is connected for fluid flow purposes to the area surrounding the cooler module  19  via inlet openings  31 ,  32  which are arranged opposite one another at the ends. The second cooler housing area  29  is connected to the area surrounding the cooler module  19  via a bottom outlet opening  33 . The outlet opening  33  is aligned with a cutout  34  in the housing section of the machine housing  7  facing the cooler module  19 , with this resulting from the octagonal cross section of the central section  13 . 
   Open air cooling of the electric motor  3  at both ends in the electrical appliance  1 , as shown in  FIG. 1 , operates as follows: 
   Air is sucked in via the inlet openings  31 ,  32  into the first cooler housing area  28  of the cooler housing  21 , as indicated by the flow direction arrows  35 ,  36  in  FIG. 1 . A suction effect which results in this inward suction, is created by the rotation of the rotor on the electric motor  3  in the stator  4 . The air that is sucked in passes through the first cooling fluid connection zone  20  and the second cooling fluid connection zone  23 , that is to say on the one hand it enters the first edge section  14  of the machine housing  7  via the aperture openings  22  and  20 , and on the other hand enters the second edge section  15  of the machine housing  7  via the aperture openings  24  and  23 . As indicated by the direction of the flow arrows  37 ,  38 , the cooling air enters the central section  13  of the machine housing  7  from there. In this case, the air flows from both ends of the electric motor  3  through the corresponding aperture openings and passages in the rotor and through the aperture openings  5  and the passages  6  in the stator  4 . This therefore represents double-ended cooling of the electric motor  3 . Furthermore, for example, the cooling air which emerges from the stator  4  passes over the outside of the casing wall  12  of the stator  4 . The casing wall  12  is separated from the housing wall  17  by the webs  16 , so that fluid can flow between the casing wall  12  and the housing wall  17 . This provides efficient air-cooling for the rotor and the stator  4 . In the central section  13 , the cooling air can flow through the aperture openings  18  in the webs  16  to the aperture openings  26  in the third cooling fluid connection zone  25 , as indicated by the flow direction arrows  39 ,  40 . The aperture openings  18  in the webs  16  therefore allow for circulating and tangential cooling air flow between the casing wall  12  and the housing wall  17 . The cooling air which transports the waste heat away enters the second cooling housing area  29  from the third cooling fluid connection zone  25  and flows out to the exterior again from the outlet opening  33 , from this area, via the cutout  34 . 
     FIG. 2  shows the machine module  2  with a second variant of a cooler module  41 . The latter will be described in the following text only where it differs from the cooler module  19 . Components which correspond to those which have already been explained above with reference to  FIG. 1  have the same reference numbers and will not be discussed in detail again. 
   A cooler housing  42  of the cooler module  41  is subdivided into a first cooler housing section with two edge sections  43 ,  44  on the one hand, and the second cooler housing section  45  on the other hand. The edge sections  43 ,  44  of the cooler housing  42  are arranged above the edge sections  14 ,  15  of the machine housing  7  in  FIG. 2 . The edge section  43  is connected for fluid flow purposes via the aperture opening  22  to the aperture opening in the first cooling fluid connection zone  20  in the machine housing  7 . The edge section  44  is connected for fluid flow purposes via the aperture opening  24  to the aperture opening in the second cooling fluid connection zone  23  of the machine housing  7 . The second cooler housing section  45  is connected for fluid flow purposes via the aperture opening  27  to the aperture openings  26  in the third cooling fluid connection zone  25  of the machine housing  7 . 
   Three supporting walls  48 ,  49 ,  50  are arranged parallel to end walls  46 ,  47  of the cooler housing  42 , which are shown on the left and right in  FIG. 2  in the interior of the cooler housing  42 . The first supporting wall  48 , which is shown on the left in  FIG. 2 , is mounted at the bottom on a supporting web of the cooler housing  42 , which is arranged between the aperture openings  22  and  27 . The supporting wall  48  separates the edge section  43 , on the left in  FIG. 2 , from the second cooler housing section  45 . This separation is not complete, since the supporting wall  48  does not extend as far as the housing wall of the cooler housing  42  shown at the top in  FIG. 2 . The second supporting wall  49  is mounted on the wall of the cooler housing  42  shown at the top in  FIG. 2 , in the second cooler housing section  45 . The second supporting wall  49  does not extend as far as the bottom of the cooler housing  42 , so that the supporting wall  49  in the second cooler housing section  45  does not represent a barrier for cooling fluid. The third supporting wall  50  is mounted on a bottom supporting web of the cooler housing  42  which is arranged between the aperture openings  27  and  24 , and its extend corresponds to that of the first supporting wall  48 . Like the first supporting wall  48 , the third supporting wall  50  represents a subdivision, which can be overcome for cooling fluid between the second cooler housing section  45  and the edge section  44  on the right in  FIG. 2 . 
   Cooling air tubes  51  for secondary cooling air are supported by the end walls  46 ,  47  and the supporting walls  48  to  50  and passed through the cooler housing  42  parallel to the axis of the electric motor  3 . In the exemplary embodiment shown in  FIG. 2  there are a total of eighty cooling air tubes  51 . These form an air-air heat exchanger  52 . 
   Closed air-circuit cooling is provided at both ends for the electrical appliance  1  shown in  FIG. 2  as follows: 
   Primary cooling air enters the machine housing  7  via the first cooling fluid connection zone  20  and the second cooling fluid connection zone  23 , as indicated by flow direction arrows  53 ,  54  in  FIG. 2 . The further cooling air flow in the machine housing  7  in the electrical appliance  1  as shown in  FIG. 2  corresponds to the cooling air flow for the cooling of the electrical appliance  1  shown in  FIG. 1  as indicated by the flow direction arrows  39 ,  40 . After passing through the third cooling fluid connection zone  25 , the cooling air which transports the heat away enters the second cooler housing section  45  of the cooler housing  42 , as indicated by flow direction arrows  55 . In the second cooler housing section  45  and in the two edge sections  43 ,  44  of the first cooler housing section of the cooler housing  42 , heat is now exchanged from the heat-emitting primary cooling air to the heat-receiving secondary cooling air which flows through cooling air tubes  51 . The primary cooling air in this case bypasses the separating walls  48 ,  50  and once again flows in the direction of the first cooling fluid connection zone  20  on the one hand, and the second cooling fluid connection zone  23  on the other hand, as indicated by flow direction arrows  56 ,  57 . This completes the cooling circuit of the primary cooling air. The flow direction of this cooling circuit results from the suction effect of the electric motor  3 . 
   A further variant of a cooler module  58  will be described in the following text with reference to  FIG. 3 . The description covers only the differences between the cooler module  58  and the cooler module  41  shown in  FIG. 2 . Components which correspond to those which have already been explained above with reference to  FIGS. 1 and 2  have the same reference numbers and will not be discussed in detail again. 
   Instead of an air-air heat exchanger, the cooler module  58  has an air-water heat exchanger  59 . This has two laminate modules  60 ,  61 , which are illustrated schematically in  FIG. 3  as blocks with a rectangular cross section. As is known, for example, from motor vehicle radiators, the cooling laminates of the laminate modules  60 ,  61  through which cooling water flows are in the form of flat structures, which are all aligned essentially parallel to the main extent plane. This main extent plane is at the same time at right angles to the bottom of a cooler housing  62  of the cooler module  58 , and on the other hand is at right angles to end walls  63 ,  64  of the cooler housing  62  with these being shown on the left and right in  FIG. 3 . This alignment of the laminate results in the flows of the primary cooling air being impeded as little as possible. The water heat exchanger  59  is supported by a supporting wall  65  in the form of a platform. A contact wall  66  of the supporting wall  55  on which the water heat exchanger  59  rests is designed such that air can pass through it, that is to say it has aperture openings for the primary cooling air. 
   These aperture openings distinguish the supporting wall  65  from the separating wall  30  in the cooler housing  21  of the cooler module  19  shown in  FIG. 1 . Otherwise, the form and the installation of the supporting wall  65  correspond to those for the separating wall  30 . The supporting wall  65  separates a first cooler housing section of the cooler housing  62  with the edge sections  43 ,  44  from the second, central cooler housing section  67 , which is bounded at the top by the supporting wall  65  in  FIG. 3 . 
   Closed air-water cooling at both ends for the cooler module variant shown in  FIG. 3  operates as follows: 
   The primary cooling air flow in the machine housing  7  corresponds to that which has been described in conjunction with the cooler module  41  shown in  FIG. 2 . The heated cooling air enters the second cooler housing section  67  of the cooler housing  62  from the third cooling fluid connection zone  25 , from where it enters the laminate modules  60 ,  61  through the contact wall  66  as indicated by flow direction arrows  68 ,  69 . In the laminate modules  60 ,  61 , the cooling air emits its heat to the cooling water of the water heat exchanger  59  as it flows through the laminates. From the laminate modules  60 ,  61  the cooling air that has been cooled down flows into the edge sections  43 ,  44  of the cooler housing  62  from where it once again flows in the direction of the aperture openings  22 ,  24  as indicated by flow direction arrows  70 ,  71 . 
   A third variant of a cooler module  72  will be described in the following text with reference to  FIG. 4  in which case this third variant can be mounted on the machine module  2  in order to complete an electrical appliance  1  instead of the cooler modules  19 ,  41  and  58 . Components of the cooler module  72  which correspond to those which have already been explained above in conjunction with  FIGS. 1 to 3  have the same reference numbers and will not be discussed in detail again. A cooler housing  73  of the cooler module  72  is subdivided into a first, bottom cooler housing area  74  and a second, cooler housing area  75 , which is essentially arranged above it. The two cooler housing areas  74 ,  75  are separated from one another in a fluid-tight manner via a separating wall  76  within the cooler housing  73 . 
   The first cooler housing area  74  is connected for fluid flow purposes to the area surrounding the cooler module  72  via an inlet opening  77 . The size and arrangement of the inlet arrangement  77  correspond to those of the outlet opening  33  of the cooler module  19  shown in  FIG. 1 . The first cooler housing area  74  is connected for fluid flow purposes to the second cooling fluid connection zone  23  via the aperture opening  24 . 
   A section of the second cooler housing area  75  on the left in  FIG. 4  is connected for fluid flow purposes to the first cooling fluid connection zone  20  of the machine housing  7  via the aperture opening  22 . The second cooler housing area  75  is connected to the area surrounding the cooler module  72  via an outlet opening  78 . The size and arrangement of the outlet opening  78  correspond to those of the inlet opening  32  of the cooler housing  21  shown in  FIG. 1 . 
   The separating wall  76  has a first separating wall section  79 , which is mounted on a bottom supporting web of the cooler housing  73  between the aperture opening  22  and the inlet opening  77 , and rises steeply from the bottom, so that the second cooler housing area  75  initially widens continuously, starting from the aperture opening  22 . A second separating wall section  80  of the separating wall  76  is adjacent to the first separating wall section  79 . This is arranged such that it falls away slightly in the cooler housing  73  so that the second cooler housing area  75  widens continuously towards the outlet opening  78 , starting from the connection between the two separating wall sections  79 ,  80 . 
   Apart from the bottom openings  22 ,  24  and  77 , the bottom of the cooler housing  73  is in the form of a plate through which no fluid can pass. In particular, a sealing plate  81  is arranged above the third cooling fluid connection zone  25  of the machine housing  7 . The latter represents a sealing device which seals the third cooling fluid connection zone  25  in such a manner that no fluid can be exchanged between the machine module  2  and the cooler module  72  through this cooling fluid connection zone  25 . 
   Open air cooling of the electrical appliance  1  at one end with the cooler module  72  operates as follows: 
   Cooling air is sucked into the first cooler housing area  74  from the outside via the inlet opening  77 . The suction effect is once again produced by rotation of the rotor in the stator  4 . Alternatively, this suction effect can be produced or assisted by a fan. No such fan is illustrated in  FIG. 4  but, for example this may be in the form of a radial fan arranged in the first edge section  14  of the machine housing  7 . Alternatively, an axial fan can also be provided. A flow direction arrow  82  indicates the entry of the cooling air into the inlet opening  77 . From the inlet opening  77 , the cooling air initially flows through the first cooler housing area  74  as indicated by a flow direction arrow  83 , and from there through the aperture opening  24  and the second cooling fluid connection zone  23  into the second edge section  15  of the machine housing  7 , as indicated by a flow direction arrow  84 . In  FIG. 4 , the cooling air then flows from the right into the electric motor  3 , and flows through the aperture openings and passages in the rotor on the one hand as well as the aperture openings  5  and the passages  6  in the stator  4  on the other hand, as described in conjunction with the cooling air flow for cooling in  FIG. 1 . Since the cooling air cannot escape upward through the third cooling fluid connection zone  25 , the cooling air flows completely through the electric motor  3  axially from right to left in  FIG. 4  as indicated by flow direction arrows  85 ,  86  and  87 . This thus represents cooling of the electric motor  3  from one end. From the central section  13 , the cooling air then flows into the first edge section  14  of the machine housing  7 , and from there via the first cooling fluid connection zone  20  and the aperture opening  22  into the second cooler housing area  75  of the cooler housing  73 , as indicated by a flow direction arrow  88 . The heated cooling air then flows from the aperture opening  22  through the continuously widening second cooler housing area  75  to the junction between the separating wall sections  79 ,  80  as indicated by a flow direction arrow  89 , to the outlet opening  78 , and from there out of the cooler housing  73 . 
     FIG. 5  shows the electrical appliance  1  of a fourth variant of a cooler module  90 , which can be mounted on the machine module  2 . The design of the cooler module  90  will be described in the following text only where it differs from the design of the cooler module  41  shown in  FIG. 2 . Components which correspond to those which have already been explained with reference to  FIGS. 1 to 4 , have the same reference numbers and will not be discussed in detail again. A cooler housing  91  of the cooler module  90  does not have the aperture opening  27 , but is closed by a sealing plate  92 . The latter therefore represents a sealing device which seals the third cooling fluid connection zone  25  of the machine housing  7 , so that no fluid can be exchanged between the machine module  2  and the cooler module  90  through the third cooling fluid connection zone  25 . 
   A closed cooling air circuit from one end for primary cooling air has the following profile in the cooler module  90 : 
   The cooling air profile in the machine housing  7  in the embodiment of the electrical appliance  1  as shown in  FIG. 5  corresponds to that in the embodiment shown in  FIG. 4 , as indicated by the flow direction arrows  85 ,  86  and  87 . 
   Heated cooling air then enters the edge section  43  on the left in  FIG. 5 , of the cooler housing  91  via the first cooling fluid connection zone  20  and the aperture opening  22 . Heat is initially exchanged between the heated primary cooling air and the secondary cooling air in the edge section  43 , which secondary cooling air flows through the cooling air tubes  51  of the air heat exchanger  52  of the cooler module  90 . A flow direction arrow  93  indicates the heated cooling air entering the edge section  43 . 
   The cooling air which has been cooled down then bypasses the supporting wall  48  as indicated by a flow direction arrow  94 , flows through the second cooler housing section  45 , as indicated by a flow direction arrow  95 , and then bypasses the supporting wall  50  as indicated by a flow direction arrow  96 , with the cooling air that has now been cooled down flowing into the edge section  44  on the right in  FIG. 5 . The cooling air that has been cooled down therefore then once again flows through the aperture opening  24  and the second cooling fluid connection zone  23  into the machine housing  7 , thus closing the primary air circuit. 
     FIG. 6  shows a further variant of a cooler module  97  for mounting on the machine module  2 . Components which correspond to those which have already been explained above with reference to  FIGS. 1 to 5  have the same reference numbers and will not be discussed in detail again. An air-water heat exchanger  99  is arranged in a cooler housing  98  of the cooler module  97 , centrally and parallel to the end wall of the cooler housing  91 , as shown on the left and right in  FIG. 6 . The air-water heat exchanger  99  has two laminate modules  100 ,  101 . Air flows through the laminates of the laminate modules  100 ,  101 . This cooling air itself exchanges heat with the cooling water which is flowing through cooling water tubes which are accommodated in the laminate modules  100 ,  101 . These modules have laminates through which cooling water flows corresponding to the laminates in the water heat exchanger  59  in the embodiment shown in  FIG. 3 . The main extent plane of the laminates of the water heat exchanger  99  in this case corresponds to that of the water heat exchanger  59 . In principle, the embodiment of the water heat exchanger  59  shown in  FIG. 3  can also be used instead of the water heat exchanger  99 . 
   The water heat exchanger  99  subdivides the interior of the cooler housing  98  into a first cooler housing section  102 , shown on the left in  FIG. 6 , and a second cooler housing section  103 , shown on the right in  FIG. 6 . The first cooler housing section  102  is connected for fluid flow purposes via the aperture opening  22  to the first cooling fluid connection zone  20  of the machine housing  7 . The second cooler housing section  103  is connected for fluid flow purposes via the aperture opening  24  to the second cooling fluid connection zone  22  of the machine housing  7 . A fluid connection is provided between the two cooler housing sections  102 ,  103  via the water heat exchanger  99 . 
   At the bottom, the cooler housing  91  of the cooler module  90  has a sealing plate  104  between the aperture openings  22  and  24 . The latter represented a sealing device, which seals the third cooling fluid connection zone  25  of the machine housing  7 , such that no fluid can be exchanged between the machine module  2  and the cooler module  97  through the third cooling fluid connection zone  25 . 
   Air-water circuit cooling from one end is provided with the cooler module  97  for the electrical appliance  1  shown in  FIG. 6  as follows: 
   The air flow in the machine housing  7  in the embodiment shown in  FIG. 6  corresponds to that in the embodiment shown in  FIGS. 4 and 5 , as indicated by the flow direction arrows  85 ,  86  and  87 . The heated cooling air enters the first cooler housing section  102  from the first edge section  14  via the first cooling fluid connection zone  20  and the aperture opening  22 , as indicated by a flow direction arrow  105 . From the first cooler housing section  102 , the cooling air passes through the water heat exchanger  99 , during which process it is cooled down by exchanging heat with the cooling air and the water, which is flowing through the laminate modules  100 ,  101 . The cooling air that has been cooled down then flows from the second cooler housing section  103  through the aperture opening  24  and the second cooling fluid connection zone  23  into the second edge section  15  of the machine housing  7 . This completes the cooling circuit for the primary cooling air. 
   The various variants of cooler modules  19 ,  41 ,  58 ,  72 ,  90 ,  97  represent a set, in which case, optionally a cooler module  19 ,  41 ,  58 ,  72 ,  90 ,  97  forming this set can be mounted on the machine module  2 , whose design on the housing side is always the same, depending on the cooling requirements and the existing circumstances. 
   Wherever an aperture opening for connection to the outside is provided for the primary cooling air guides as described above, this can be designed such that it is protected against the ingress of water and dust. 
   As an alternative to or in addition to the aperture openings  18  in the webs  16 , a tangential flow of cooling fluid between the stator casing  12  and the housing wall  17  can be achieved by the webs  16  being shaped such that the stator casing  12  rests on it only in places, so that intermediate spaces are created between the stator casing  12  and the webs  16 , allowing a tangential flow through them.