TECHNICAL FIELD
The subject matter described herein, in general, relates to an automotive alternator driven by an internal combustion (IC) engine and, in particular relates to a cooling mechanism for an automotive alternator.
BACKGROUND
Alternators are used in all types of motor vehicles, such as passenger cars and trucks, to meet the electrical power demand of the vehicles. Automotive alternators are mechanically driven using a drive belt wrapped on a pulley connected to a crankshaft of a vehicle's internal combustion engine. The belt drives the pulley which in turn rotates an internal rotor assembly of the alternator to generate alternating current (AC) electrical power from a stator winding of the alternator. This AC power is rectified to a direct current (DC) supply.
Present day requirements demand for efficient vehicle design, cost, and performance, which in turn place emphasis on having more efficient alternator designs. Further, there is also a need to increase the output of the alternator at lower speeds. Moreover, there is also a need for an improved cooling mechanism to control temperature rise of the various parts of the alternator, especially when a high electrical output is provided by the alternator. This is usually achieved by increasing the rate of flow of cooling air passing through various parts of the alternator; however, such a mechanism directly leads to an increase in operating noise.
In addition to above said challenges, there is a growing need to enhance power density of the alternator to meet the under hood packaging requirements.
Fig. 1 illustrates a sectional view of a conventional automotive alternator 100. The alternator 100 includes a rotor 105 having an exciting winding and a pair of pole cores, which are disposed circumferentially on a shaft 110. The rotor 105 is supported at two ends of the shaft 110 by a front end bracket 115 and a rear end bracket 120. The front-end bracket 115 may be a drive end bracket (hereinafter, referred to as drive end (DE) frame 115), and the rear-end bracket 120 may be a slip ring end bracket (hereinafter, referred to as slip ring end (SRE) frame 120). A stator 125 is clamped between the DE frame 115 and the SRE frame 120. The stator 125 includes a stator core, made of thin stacked laminations to form a hollow cylinder. The stator core includes numerous slots provided in an axial direction of the stator

core, disposed circumferentially in an inner circumferential side of the stator core. Coils of insulated conductors are inserted into the slots of the stator core.
In order to transmit a rotational torque from the vehicle engine to the shaft 110, a pulley 130 is assembled at the drive end or the front end of the shaft 110. The engine transmits the rotational torque to the pulley 130 by means of a belt. Slip rings for supplying current to rotor 105 are assembled on shaft 110 at the rear end. Consequently, an alternating current (AC) is generated in the stator windings and the AC current is recfified and regulated by a rectifier and regulator assembly 135 connected to the stator 125 to give a regulated DC output. The DC output is fed to the vehicle battery (not shown in the figure) thereby charging the same.
During the operation of the alternator 100, the sub-assemblies such as rotor 105, stator 125, and the rectifier and regulator assembly 135 are heated up due to losses in the sub¬assemblies such as, copper loss in stator 125 and field windings, rectification loss and switching loss in the rectifier and regulator assembly 135, and frictional losses in the front and rear bearings of the DE frame 115 and the SRE frame 120. In order to provide cooling, the DE frame 115 and SRE frame 120 are typically ventilated to allow airflow through the alternator 100. For this purpose, alternator 100 accommodates two centrifugal fans namely, a drive end (DE) fan 140A and a slip ring end (SRE) fan 1408 provided on two opposite axial ends of the rotor 105. The DE fan 140A is disposed at a front axial end of the rotor 105 and the SRE fan 140B is disposed at a rear axial end of the rotor 105.
The DE fan 140A draws air axially through air intake openings 150A and 150B provided in the DE frame 115. The air drawn from the air intake openings 150A and 150B follows a path depicted by the air flow path 145A and 145B respectively. The drawn air exits out through the air discharge apertures 155A and 155B after cooling the front end winding basket of the stator 125. The air intake openings 150A and 150B are provided on the axial side surfaces of the DE frame 115 and the air discharge apertures 155A and 155B are provided around the circumference of the DE frame 115. Additionally, the SRE fan 1406 draws air such that the drawn air follows a path depicted by the air flow path 160A and 160B to enter the SRE frame 120 through a first set of apertures including an aperture 165A and an aperture 165B. The first set of apertures 165 A and 165B may be hereinafter referred to as the first set of apertures 165. The first set of apertures 165 is provided on an axial side of the SRE

frame 120. The axially drawn air exits out radially through a second set of apertures including an aperture 170A and an aperture 170B after cooling the rectifier and regulator assembly 135 and the rear end winding basket of stator 125. The second set of apertures 170A and 170B may be hereinafter referred to as the second set of apertures 170. Further, the second set of apertures 170 is provided on the circumference of the SRE frame 120.
In order to achieve reduction in size or compactness and to minimize losses due to heat dissipation for providing a higher output, an efficient cooling system is desired. The conventional alternator with the above construction has numerous disadvantages such as lower output at idling speed of engine, lower efficiency, and lower power density. Further, the conventional alternator suffers from the disadvantage of having a small axial inlet openings at the DE frame 115, for a given frame size, when a large drive-end bearing is used.
SUMMARY
The subject matter described herein is directed to an alternator for providing high electrical output and increased cooling of underlying parts such as the stator coil, rotor winding, and rectifier and regulator assembly. In addition, the alternator described herein is compact and has low operating noise.
According to one aspect of the present subject matter, the alternator includes a rotor supported by a DE frame and a SRE frame. In one embodiment, the rotor has a pair of Lundell-type pole cores. The alternator also includes a stator, supported by the frames, and disposed so as to cover an outer circumference of the rotor. The stator includes a cylindrical stator core in which a plurality of slots, having grooves lying in an axial direction, is disposed circumferentially so as to open onto an inner circumferential side. The stator further includes a stator coil installed in the stator core to include a predetermined winding construction.
The proposed alternator includes a first set of apertures disposed at the side surfaces i.e. the axial side surfaces of the SRE frame, and a second set of apertures disposed around the circumference of the SRE frame.
The proposed alternator further includes a third set of apertures disposed around the circumference of the DE frame. The third set of apertures performs the funcfion of air intake for radially drawing air inside the DE frame. Further, the third set of apertures also performs the function of the air discharge. For this purpose, a baffle plate is mounted on an inner side

wall of the DE frame. The baffle plate divides the third set of apertures into a first passage for drawing in air inside the DE frame, and a second passage for radially expelling hot air subsequent to cooling of alternator sub-assemblies disposed at the DE. The alternator also includes a DE fan and a SRE fan disposed at two opposite axial ends of the rotor.
In another embodiment, cooling of the alternator could be further improved by providing the multiple stator core apertures in the stator core, at predetermined intervals, extending from the inner circumferential surface of the stator core to the outer circumferential surface.
The alternator as explained herein, provides a superior cooling mechanism. The multiple set of apertures provided for air intake and air discharge provide effective air circulation thereby cooling the alternator sub-assemblies and reducing the losses owing to heat dissipation. Additionally, in one embodiment, conductors with rectangular cross-section are utilized in order to reduce the copper losses in the stator windings and to realize higher alternator efficiency with the enhanced cooling mechanism.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features, aspects, and advantages of the subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where;
Fig. 1 illustrates a sectional view of a conventional automotive alternator.
Fig. 2 illustrates a sectional view of an exemplary automotive alternator, according to a first embodiment of the present subject matter.
Fig. 3 illustrates a sectional view of an exemplary alternator, according to a one embodiment of the present subject matter.
Fig. 4 illustrates a perspective view of the stator assembly of Fig. 3, according to an embodiment of the subject matter.

Fig. 5 illustrates a perspective view of a stator core of the stator of Fig. 4, according to an embodiment of the subject matter.
Fig. 6 illustrates a perspective view of a drive end (DE) frame according to an embodiment of the subject matter.
Fig. 7 illustrates a perspective view of a baffle plate mounted on inner axial surface of the DE frame of Fig. 6, according to an embodiment of the subject matter.
DETAILED DESCRIPTION
An alternator for automobiles with an efficient cooling mechanism, higher output, and reduced noise is described herein. In one embodiment, the alternator includes a Lundell-type rotor with N and S poles formed alternately in a circumferential direction, a stator including a stator core and a poly-phase stator winding associated with the stator core, and a drive end (DE) frame and a slip ring end (SRE) frame for supporting the rotor, the stator and a rectifier and regulator assembly.
The stator core comprises laminated steel plates formed with a plurality of slots extending in the axial direction of the stator core. The stator core employs wire conductors laced into the stator core winding slots. In one embodiment, the wire conductors may have round cross-section. In another embodiment, the vvire conductors may have rectangular cross-section. In yet another embodiment, round wire conductors can be formed into rectangular sections corresponding to slot portions only.
The conductors are formed as either segmented or continuous wire conductors that allow high slot fill. This lowers the resistance of the conductors, thereby reducing copper losses. At the same time, the number of poles can be suitably increased, which helps to reduce stator winding overhang leading to reduced winding resistance and reduced leakage inductance.
In order to cool the sub-assemblies of the alternator, the SRE frame includes a first set of apertures and a second of apertures for air ventilation. Further, the DE frame includes a third set of apertures provided around circumference of the DE frame. According to an aspect of the present subject matter, a baffle plate fixed to the inner side wall of the DE frame divides the third set of apertures into a first passage and a second passage.
Accordingly, cooling air is drawn radially through the first passage by a DE fan attached to the rotor. The air drawn from the first passage is fed downwardly along the baffle

plate to cool a DE bearing housing while passing through the fins provided around the DE bearing housing. Further, the drawn air is discharged radially through the second passage after cooling a DE basket of stator assembly. In one embodiment, to minimize the temperature rise of the stator further, the stator core with multiple stator core apertures, may be employed. The multiple stator core apertures are disposed on the circumferential side of the stator core to facilitate air circulation inside the stator core.
Fig. 2 illustrates a sectional view of an exemplary automotive alternator 200 according to the first embodiment of the present subject matter. The alternator 200 includes a rotor 105 having a winding and a pair of claw shaped pole cores that are disposed circumferentially about a shaft 110. The alternator 200 includes a pair of frames such as a DE frame 115 and an SRE frame 120. The frames i.e. DE frame 115 and SRE frame 120 are typically cast from aluminum. The DE frame 115 and the SRE frame 120 together support the stator 125, the rotor 105, and other components of the automotive alternator 200.
The stator 125 acts as an armature and includes a stator core which is cylindrical and a stator coil having a predetermined winding construction. The stator core includes a number of slots having grooves, disposed on circumferential surface of the stator core, lying in an axial direction. The grooves receive a plurality of wire conductors that are either circular or rectangular in cross-section. In yet another embodiment, the conductors with circular cross-section may be formed into rectangular section for the slot portion. In such an embodiment, advantageous features of conductors with circular cross-section as well as rectangular cross-secfion are retained. The rectangular cross section of the conductors is advantageous as the slot fill factor of stator winding is enhanced by use of conductors with rectangular cross section, as compared to conductors with circular cross section, thereby reducing the copper loss of alternator. The wire conductors may be segmented and the stator winding may be formed by joining appropriate ends of the wire conductors through relevant joining process such as welding or brazing or soldering. In another embodiment, the wire conductors may be continuously wound around the stator core.
The alternator 200 further includes a pulley 130 fastened to a front end of the shaft 110 and a rectifier and regulator assembly 135 whose output is connected to a battery (not shown). Generally, the alternator 200 is driven by a crankshaft of the vehicle through a belt

passing over the pulley 130. When the crankshaft rotates, the belt drives the pulley 130, which in turn rotates the shaft 110 and the rotor 105 to generate alternating current (AC) in the stator coil. The rectifier and regulator assembly 135 then converts the generated AC into direct current (DC) and supplies DC to the battery via an electrical bus to charge the battery.
Further, in order to improve overall efficiency of the alternator 200, the temperature rise of the inner sub-assemblies such as the stator 125, the rotor 105, and the rectifier and regulator assembly 135 of the alternator 200 is controlled by cooling the sub-assemblies. In one embodiment, cooling is provided by air ventilation with the help of a drive end (DE) fan 140A and a slip ring end (SRE) fan HOB attached to rotor 105. The two fans 140A and HOB draw air into the alternator 200 and expel heat from the sub-assemblies through circulation of drawn air.
For the purpose, the SRE fan HOB draws air such that the drawn air follows the air flow path 160A and 160B to enter the SRE frame 120 through a first set of apertures including an aperture 165A and an aperture 165B, disposed at the side surface i.e. the axial side surface of the SRE frame 120. The alternator 200 further includes a second set of apertures comprising an aperture 170A and an aperture 170B, disposed around the circumference of the SRE frame 120. The first set of apertures 165A and 165B, the second set of apertures 170A and 170B and the air flow paths 160A and 160B may be hereinafter referred to as the first set of apertures 165, the second set of apertures 170 and, the air flow paths 160 respectively.
In operation, the rotation of the SRE fan HOB draws air, along air flow path 160 inside the SRE frame 120 through the first set of apertures 165. The blades of the SRE fan HOB redirect the drawn air such that the drawn air follows a radial flow, as illustrated by the air flow paths 160, and finally exit the alternator 200 through the second set of apertures 170 after cooling the rectifier and regulator assembly 135, and a SRE basket 125B of stator assembly 125.
In an embodiment of the present subject matter, for cooling the sub-assemblies provided at the DE frame 115, a third set of apertures comprising an aperture 220A and an aperture 220B is provided. A baffle plate 210, dividing the third set of apertures into a first passage and a second passage, is fixed to the inner side wall of the DE frame 115. The details

of the baffle plate 210 are later elaborated in Fig. 7. The apertures 220A and 220B may be hereinafter referred to as the third set of apertures 220. In the DE frame 115, the third set of apertures 220 are formed in a radial direction, which extends over the DE basket 125A of the stator 125 from the sides of the DE frame 115.
In one embodiment, the baffle plate 210 forms the first passage between the baffle plate 210 and the inner side wall of the DE frame 115, and the second passage between the baffle plate 210 and a side surface of the rotor 105 to which the DE fan 140A is attached. The first passage serves as an air intake passage for radially drawing air inside the DE frame 115. The second passage serves as the air discharge passage for radially discharging hot air subsequent to cooling of alternator sub-assemblies provided on the DE frame 115. Thus, the third set of apertures 220 in the DE frame 115 performs both the functions of air intake and air discharge.
The rotation of the DE fan 140A, attached to the front axial end of the rotor 105, draws air inside the DE frame 115 through the first passage provided inside the third set of apertures 220. The air is drawn through the first passage such that the drawn air follows air fiow paths 280A and 280B. The air fiow paths 280A and 280B may collectively referred to as the air flow paths 280.
As the drawn air is fed downwardly from the first passage along the baffle plate 210, a plurality of fins 250 attached to the inner circumference of the DE frame 115, direct the air to impinge on a bearing housing 260 that holds the drive-end bearing 270. This results in minimizing the bearing temperature. The fins 250 and the bearing housing 260 have been depicted clearly in Fig. 6. Further, the drawn air is discharged through the second passage after cooling the DE basket 125A of the stator 125.
Fig. 3 illustrates a sectional view of an exemplary alternator 300, according to one embodiment of the present subject matter. The alternator 300 resembles the construction and working of the alternator 200 as described with respect to Fig. 2. The alternator 300 includes a stator 305 having a stator core and multiple stator core apertures 310A and 310B, collectively referred to as the stator core apertures 310, disposed on the circumferential side of the stator core.

As explained previously, when the shaft 110 and the SRE fan 1408 are rotated, the air is drawn, along the air flow path 160, axially through the first set of apertures 165 of the SRE frame 120 and the drawn air is discharged out of the SRE frame 120 through the second set of apertures 170 in a radial direction.
Further, the rotation of the DE fan 140A draws air, along the air flow path 280, inside the DE frame 115 through the first passage of the third set of apertures 220, in a radial direction. The drawn air is then redirected to follow a radial flow, as illustrated by the air flow path 280, by the DE fan 140A. The redirected air is finally discharged through the second passage formed inside the third set of apertures 220 in the radial direction. In said embodiment, additional air along the air flow paths 315A and 315B, also referred to as the air flow paths 315, is drawn radially through the stator core apertures 310. The drawn air is redirected to follow a radial flow by the fans 140A and 1406. The air drawn through the stator core apertures 310 finally exits through second set of apertures 170 provided on the SRE frame 120 and the second passage of the third set of apertures 220 provided on the DE frame 115. The circulation of the air through the stator core apertures 310 provides efficient cooling of the stator 305 thereby providing high alternator efficiency.
Fig. 4 illustrates a perspective view of the stator 305 of the Fig. 3, according to an embodiment of the present subject matter. The stator 305, according to the embodiments described with respect to Fig. 3 of the alternator 300, includes a stator core 405 and a stator coil 410. The stator coil 410 includes a predetermined winding construction. The stator coil 410 can be formed by conductors 415 that are either segmented or continuous. The conductors 415 are wound around the inner circumferential side of the stator core 405. The stator core 405 includes a number of slots extending from the first end of the cylindrical stator core 405 to the second end of the stator core 405. The slots are disposed on the circumferential side of the stator core 405, in an axial direction and have grooves. The grooves receive a plurality of conductors 415 that are either circular or rectangular in cross-section.
The stator core 405 includes stator core apertures 310 on the circumferential side of the stator core 405 to facilitate the flow of air through the stator core 405. The construction of the stator core 405 with stator core apertures 310 is elaborated in the description of Fig. 5.

Fig. 5 illustrates a perspective view of the stator core 405 of the stator 305, according an embodiment of the present subject matter. The stator core 405 as shown in Fig. 5 includes the multiple stator core apertures 310 on the circumferential side of the stator core 405 to facilitate the flow of air through the stator core 405. The stator core 405 includes a plurality of stack of punchings 505 packed in annular arrays of layer. The annular layer includes a predetermined number of punchings 505 arranged in a common plane. The annular layer of 505 is held between core stacks 510A and 510B to form the stator core 405, This kind of an arrangement facihtates gaps between adjacent stacks of punchings 505 thereby forming the stator core apertures 310. The stator core apertures 310 facilitate air circulation across the stator 305 resulting in cooling the stator 305.
In another embodiment, it is also possible to repeat the annular layers at multiple axial positions of the stator core 405 to optimize the cooling performance.
In the above described embodiments, the conductors for the stators 125 and 305 are made of copper. Mowever, depending on preferences of a user, aluminium or copper clad aluminium wire conductors may also be used. Further, it is also possible to use complex conductors comprising both rectangular conductor portion and round conductor portion or round conductor portion with any other conductor portion that suits the slot profile of the stators 125 and 305.
Fig. 6 illustrates a perspective view of the DE frame 115 indicating the fins 250 provided on inner surface of the DE frame 115. The third set of apertures 220 as depicted in the fig. are provided on the circumferential surface of the DE frame 115, according to an embodiment of the subject matter.
Fig. 7 illustrates a perspective view of the baffle plate 210 mounted on inner axial surface of the DE frame 115, according to an embodiment of the subject matter.
As previously explained, fresh air is drawn inwardly through the first passage and the drawn air gets directed along the fins 250 to impinge on the bearing housing 260, in order to cool the bearing housing 260. The second passage serves as the air discharge passage for radially discharging hot air subsequent to cooling of alternator sub-assemblies provided on the DE frame 115. The baffle plate 210 prevents the mixing of freshly drawn air through the first passage with the hot air expelled out through the second passage. Thus, owing to deployment

of the baffle plate 210, the third set of apertures 220 performs both the functions of air intake and discharge. Additionally, the baffie plate 210 serves as a shroud for the DE fan 140A.
The previously described versions of the subject matter and its equivalent thereof have many advantages, including those, which are described below. The subject matter described herein provides an alternator with an efficient cooling mechanism for enhancing the power output of the alternator. The air drawn from multiple sets of apertures provided at the SRE frame 120 and a DE frame 115 effectively cool the alternator sub-assemblies.
Additionally, stator core apertures 310 provided on the stator core 405 facilitate air circulation through the stator core 405 thereby cooling the same. As a consequence of air circuladon through the various sub-assemblies, temperature rise across the sub-assemblies is minimized. Advantageously, the proposed alternator is compact in size, provides high electrical output and is efficient.
While certain features of the claimed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the claimed subject matter.

lAVe claim:
1. An automotive alteator (200) comprising:
a rotor (105) mounted on a shaft (110);
a sLIring end (SRE) frame (120) coupled to said rotor (105) at a rear end for supporting said rotor (105), wherein said SRE frame comprises:
a first set of apertures (165) disposed on an axial side of said SRE frame (120); and
a second'set of apertures (170) disposed around the circumference of said SRE frame (120);
a drive end (DE) frame (115) coupled to said rotor (105) at a front end for supporting said rotor (105);
a stator (125) supported by said DE; frame (115) and said SRE frame (120), said stator (125) being disposed so as to cover an outer circumference of said rotor (105), said stator (125) comprising,
a cylindrical stator core wherein a plurality of slots extend from a first end of said stator core to a second end of said stator core in an axial direction, said slots being disposed circumferenfially; and
stator coils installed in said stator core to form a predetermined winding construction;
a pulley (130) fastened to a front end of said shaft (110); a rectifier and regulator assembly (135) disposed in said SRE frame (120); a DE fan (140A) disposed at a front axial end of said rotor (105); and a SRE fan (1408) disposed at a rear axial end of said rotor (105), wherein upon operafion of said SRE fan (HOB), air is drawn axially inside said SRE frame (120) through said first set of apertures (165), and wherein said air drawn through said first set of aperture (165) is discharged radially through said second set of apertures (170); characterized in that, said DE frame (115) comprises,
a third set of apertures (220) disposed around the circumference of said DE frame (115); and

a baffle plate (210) attached to an inner side wall of said DE frame (115), wherein said baffle plate (210) divides said third set of apertures (220) into a first passage formed between said baffle plate (210) and said inner side wall of said DE frame (115), and a second passage formed between said baffle plate (210) and a side surl^ce of said rotor (105), and wherein upon operafion of said DE fan (140A), air is drawn radially inside said DE frame (115) through said first passage and wherein said air drawn through said first passage is discharged radially through said second passage.
2. The automotive alternator (200) as claimed in claim 1, wherein one or more fins (250) attached to an inner circumference of said DE frame (115), direct air drawn through said first passage to impinge on a bearing housing (260) such that said drawn air cools said bearing housing (260).
3. An automotive alternator (300) comprising:
a rotor (105) mounted on a shaft (llO);
a slip ring end (SRE) frame (120) coupled to said rotor (105) at a rear end for supporting said rotor (105), wherein said SRE frame comprises,
a first set of apertures (165) disposed on an axial side of said SRE frame (120); and
a second set of apertures (170) disposed around the circumference of said SRE frame (120);
a drive end (DE) frame (115) coupled to said rotor (105) at a front end for supporting said rotor (105);
a stator (125) supported by said DE frame (115) and said SRE frame (120), said stator (125) being disposed so as to cover an outer circumference of said rotor (105), said stator (125) comprising,
a cylindrical stator core (405) wherein a plurality of slots extend from a first end of said stator core (405) to a second end of said stator core (405) in an axial direction, said slots being disposed circumferenfially;
a plurality oi stator core apertures (310) disposed in said stator core (405) at predetermined intervals extending from an inner circumferential

surface to an outer circumferential surface of said stator core (405) to radially draw air inside the stator core (405); and
stator coils (410) installed in said stator core (405) to form a predetermined winding construction; a pulley (130) fastened to a front end of said shaft (110); a rectifier and regulator assembly (135) disposed at said SRE frame (120); a DE fan (140 A) disposed at a front axial end of said rotor (105); and
a SRE fan (HOB) disposed at a rear axial end of said rotor (105), wherein upon operation of said SRE fan (HOB), air is drawn axially inside said SRE frame (120) through said first set of apertures (165) and wherein said air drawn through said first set of aperture (165) is discharged radially through said second set of apertures (170); characterized in that, said DE frame (115) comprises:
a third set of apertures (220) disposed around the circumference of said DE frame (115); and
a baffle plate (210) attached to an inner side wall of said DE frame (115), wherein said baffle plate (210) divides said third set of apertures (220) into a first passage formed between said baffle plate (210) and said inner side wall of said DE frame (115) and a second passage formed between said baffle plate (210) and a side surface of said rotor (105). and wherein upon operation of said DE fan (140A), air is drawn radially inside said DE frame (115) through said first passage and wherein said air drawn through said first passage is discharged radially through said second passage, and
wherein upon operation of said SRE fan (HOB) and DE fan (HOA) air drawn through said stator core apertures (310) along radial direction is discharged through said third set of apertures (220) and said second set of apertures (170). 4. The automotive alternator (200) as claimed in claim 3, wherein one or more fins (250) attached to an inner circumference of said DE frame (115), direct air drawn through said first passage to impinge on a bearing housing (260) such that said drawn air cools said bearing housing (260).

5. The automotive alternator as claimed in any of the preceding claims, wherein said
predetermined winding is formed of continuous or segmented conductors.
6. The automotive alternator as claimed in any of the preceding claims, wherein said
predetermined winding is formed of conductors having one or more of round or
rectangular cross section.