CA1087670A - Rotor structure for an air-cooled dynamoelectric machine - Google Patents
Rotor structure for an air-cooled dynamoelectric machineInfo
- Publication number
- CA1087670A CA1087670A CA293,064A CA293064A CA1087670A CA 1087670 A CA1087670 A CA 1087670A CA 293064 A CA293064 A CA 293064A CA 1087670 A CA1087670 A CA 1087670A
- Authority
- CA
- Canada
- Prior art keywords
- air
- air inlet
- rotor
- spider arms
- cover plates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Iron Core Of Rotating Electric Machines (AREA)
- Motor Or Generator Cooling System (AREA)
Abstract
A ROTOR FOR A ROTARY ELECTRIC MACHINE
ABSTRACT OF THE DISCLOSURE
A rotor structure draws surrounding air into chambers formed by adjacent pairs of spider arms through air inlet holes in cover plates enclosing the spider arms, due to the fan action of the spider arms upon rotation of the rotor. The air in the chambers then flows into the stator after cooling an annual yoke and windings. During this period, the high temperature portion of the machine is cooled by this.
According to the ventilation structure of the present invention, the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other, thus reducing windage loss and increasing cooling efficiency.
ABSTRACT OF THE DISCLOSURE
A rotor structure draws surrounding air into chambers formed by adjacent pairs of spider arms through air inlet holes in cover plates enclosing the spider arms, due to the fan action of the spider arms upon rotation of the rotor. The air in the chambers then flows into the stator after cooling an annual yoke and windings. During this period, the high temperature portion of the machine is cooled by this.
According to the ventilation structure of the present invention, the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other, thus reducing windage loss and increasing cooling efficiency.
Description
BACKGROUND OF THE INVENTION
This invention relates to the construction of a rotor for a rotary electric machine, and more particularly to a ventilation system for effectively cooling the high temperature portion of the rotor in a rotary electric machine by means of the air admitted into the rotor by the fan action of the spider arms of the rotor.
In a rotary electric machine in which the high temperature portion is cooled by air drawn into the rotor by the fan action of the spider arms of the rotor, a large volume of air flow is required for sufficient cooling. To obtain this large air flow, the fan action of the spider arms must be sufficient. However, even if sufficient air flow is obtainable, the air will not be utilized very efficiently.
The ventilation system must be such that its windage is as small as possible, while a sufficient volume of air flow for cooling is secured.
The typical ventilation system of a rotor for a conventional rotary electric machine is illustrated in U.S.
Patent 3,160,770 issued December 8, 1964 to P. Asantcheeff.
In the case of the ventilation system illustrated in such patent, the air inlet holes are disposed at a position overlapping in the axial direction two sheets of cover plates, so that there are the following shortcomings; ~1) The air flows admitted into the rotor from the respective air inlet holes run against each other in the rotor. The colliding air produces an eddy, resulting in turbulence and preventing the air from 1Owing in the rotor. As a result, sufficient air flow as needed for cooling the high temperature .
B - ~ ~:
. .
.. . .
~76~0 , portion of the machine cannot be secured.
This invention relates to the construction of a rotor for a rotary electric machine, and more particularly to a ventilation system for effectively cooling the high temperature portion of the rotor in a rotary electric machine by means of the air admitted into the rotor by the fan action of the spider arms of the rotor.
In a rotary electric machine in which the high temperature portion is cooled by air drawn into the rotor by the fan action of the spider arms of the rotor, a large volume of air flow is required for sufficient cooling. To obtain this large air flow, the fan action of the spider arms must be sufficient. However, even if sufficient air flow is obtainable, the air will not be utilized very efficiently.
The ventilation system must be such that its windage is as small as possible, while a sufficient volume of air flow for cooling is secured.
The typical ventilation system of a rotor for a conventional rotary electric machine is illustrated in U.S.
Patent 3,160,770 issued December 8, 1964 to P. Asantcheeff.
In the case of the ventilation system illustrated in such patent, the air inlet holes are disposed at a position overlapping in the axial direction two sheets of cover plates, so that there are the following shortcomings; ~1) The air flows admitted into the rotor from the respective air inlet holes run against each other in the rotor. The colliding air produces an eddy, resulting in turbulence and preventing the air from 1Owing in the rotor. As a result, sufficient air flow as needed for cooling the high temperature .
B - ~ ~:
. .
.. . .
~76~0 , portion of the machine cannot be secured.
(2) In order to cool the hot air after it has been used to cool the high temperature portion of the machine and to discharge it therefrom, an air cooler is disposed at an air outlet of the machine. This air cooler is rather complex in its construction, so that the resistance in the path of the air is comparatively large. To obtain a cooler that operates with good cooling efficiency, the air pressure at the air inlet portion of the cooler must be high.
(3) Owing to the turbulent flow generated in the rotor, the air discharged from the rotor does not necessarily flow through the gap between the end cover and the rotor. In other words, the air drawn into the rotor is mostly discharged as it is, without being utilized for cooling. The fact that the air drawn into the rotor by the fan action of the spider arms may be discharged without having been used for cooling represents an increase of windage.
; SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to improve the cooling efficiency in a rotary electric machine by effective ventilation of the machine.
It is another object of this invention to provide a rotor for such a machine having a ventilation structure capable of securing an air flow required for cooling the high temperature portion of the machine with a minimum of windage loss.
- To this end the invention consists of a rotor for a rotary electric machine comprising: (a) a rotatable shaft, (b) radially projecting spider arms secured to said rotatable shaft, (c) an annular yoke having ducts extending in a radial direction, said yoke being mechanically coupled to radially outer ends of the spider -1'~)87670 arms, (d) cover plates defining a chamber between each pair of spider arms and an inner periphery of said annular yoke while retaining a gap between said inner periphery and outer peripheries of said cover plates, each of said cover plates having an air inlet hole through which air is drawn into the chamber by rotation of said spider arms, and (e) magnetic poles projecting from an outer periphery of said annular yoke, (f) characterized in that the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a longitudinal, partially sectional view~
of a first embodiment of a rotor having a ventilation structure in accordance with the present invention, and particularly shows the flow of air utilised for cooling during operation of the machine.
Fig. 2 shows a partial plan view of the rotor illustrated in Fig. 1.
Fig. 3 shows a characteristic diagram including a ventilation curve (Hl) and a windage curve (Wl) for a rotary electric machine having a conventional ventilation structure, as well as a ventilation curve (H2) and a windage curve (W2) for a rotary electric machine having a ventilation structure in accordance with the present invention.
Fig. 4 shows a partial plan view of a second embodiment of rotor in accordance with the present invention.
- Fig. 5 shows a partial plan view of a third embodiment of rotor in accordance with the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
In Figs. 1 and 2, the rotary electric machine comprises a rotor 4 mounted on a rotatable shaft 2 and a .
.: ~ . .
1~767t~
stator 8 fixed to a base stand 6. Each of a plurality of spider arms 10 has a predetermined width in both the axial and radial.
directions; the radially inner end of each spider arm is fixed to the shaft 2. The outer peripheral ends of the spider arms 10 are connected to an annular yoke 18 by way of cotters 16.
Numerous radial ducts 20 are formed in the annular yoke 18 spaced apart in its axial direction. Cover plates 12 and 14 supported by the spider arms 10 close the openings of the chambers formed between each adjacent pair of spider arms in the axial direction. A predetermined gap 22 or 24 is formed between the outer peripheral end of the cover plate 12 or 14 and the inner periphery of the annular yoke 18. At the outer periphery of the annular yoke 18 there are a plurality of projecting magnetic poles 26. On both sides of the projecting magnetic poles 26 there is an end ring 28 which supports both ends of a damper coil provided on the projecting magnetic poles 26. The rotor 4 is composed of the spider arms 10, the cover plates 12 and 14, the annular yoke 18 and the projecting magnetic poles 26.
A stator yoke 30 is provided with numerous ducts 34 in extending the radial direction and face the projecting magnetic poles 26 across a small gap 32. An armature coil 36 is disposed on the outer periphery of the stator yoke 30 facing the projecting magnetic poles 26. The stator yoke 30 is fixed to the base stand 6 by means of a stator frame 38. Two end covers 40 and 42 are mounted on the stator frame 38 so as to cover the stator yoke 30 and the armature coil 36. Formed between the rotor 4 and each of the end covers 40 and 42 are :
gaps 44 and 46 through which cooling air flows into the end -covers 40 and 42. Disposed on the stator frame 38 is an air cooler 48 for cooling the hot air after it has been utilized ~ -- ` 10876'70 for cooling the high temperature portion of the machine.
In respective cover plates 12 and 14, a number of air inlet holes 50 and 52 are disposed. The holes 50 in the plate 12 and the holes 52 in the plate 14 are staggered so as not to be aligned in the axial direction. There is only one air inlet hole 50 or 52 between each ad~acent pair of spider arms 10.
Arrows shown in Fig. 1 represent the flow of air during operation of the rotor 4. Air drawn into the chamber of the rotor 4 from the outside of the machine through the inlet holes 50 and 52 by the fan action of the spider arms 10 passes into the region of the stator 8 through the ducts 20 on one hand, and simultaneously into the end covers 40 and 42 through the gaps 44 and 46 after having passed through the gaps 22 and 24.
Air discharged from the ducts 20 to the gap 32 flows in the stator frame 38 through the ducts 34.
Air admitted into the end covers 40 and 42 flows in the gap 32 due to the fan action of the projecting magnetic poles 26 and then is divided into two groups. One flows in the stator frame 38 through the ducts 34 and the other flows in the stator frame 38 through the end portion of the ~5 armature coil 36.
All the air flowing in these different routes comes together at the stator frame 38 and is then discharged to the outside of the machine, after having been cooled by the air coolers 48 mounted on the stator frame 38.
Since the air inlet hole 50 on the cover plate 12 and the air inlet hole 52 on the cover plate 14 are staggered, air currents admitted into the chamber of the rotor 4 will not ~
collide with each other in the chamber. Thus turbulence is ~ ~ -- 6 - ~
: . - - . ............ - . . .
- . : . . :
10876t70 eliminated or reduced in the chamber of the rotor 4. Air in this chamber can readily flow in the ducts 20 of the annular yoke 18 and out of the gaps 22 and 24 to the outside of the chamber. As a result, a sufficient air flow into the chamber through the air inlet holes 50 and 52 to refrigerate the high temperature portion of the machine is ensured. In addition, the air, once it has passed through the gaps 22 and 24, flows into the end covers 40 and 42 through the gaps 44 and 46 without flowing back into the chamber through the air inlet holes 50 and 52. The air in the end covers 40 and 42 is used to cool the annular yoke 18, the projecting magnetic poles 26, the stator yoke 30 and the armature coil 36. In short, the air drawn into the chamber due to the fan action of the spider arms 10 is virtually 100% used for cooling. Accordingly, cooling of the machine can be achieved without increasing the windage, and this corresponds to a substantial improvement in cooling efficiency.
The action and effect of the present arrangement will now be explained by referring to Fig. 3 which relates to a 225 MVA rotary electric machine to which a ventilation structure in accordance with the present invention has been applied. The ventilation curve Hl and the windage curve Wl show the relationship between the amount of air flow Q(m3/S) and the air pressure H (mm Ag) and the relationship between the amount of air flow Q and the windage W (KW), respectively, in the vicinity of the air inlet of the air cooler 48.when the respective air inlet holes on two cover plates are aligned in the axial direction. On the other hand, the ventilation curve H2 and the windage curve W2 show the relationship between the amount of air flow Q and the air pressure H and the relationship between the amount of air flow Q and the 1~8767~
, windage W, respectively, in the vicinity of the air inlet of the air cooler 48 for a machine having the ventilation structure in accordance with the present invention; i.e.
staggered air inlet holes.
As the result of experiments, it was found that an air flow of at least 150 m3/S is necessary to cool the high temperature portion of the 225 MVA machine. According to Fig. 2, in the oase of a machine having a ventilation structure wherein the air inlet holes are aligned in the axial direction, it was found that, for an air flow of 150 m3/S, the windage Wl corresponds to 820 KW and the air pressure Hl in the vicinity of the air inlet of the air cooler corresponds to 15 mm Ag. On the other hand, for the machine having a ventilation structure wherein the air inlet holes 50 and 52 on the cover plates 12 and 14 are not aligned and for an air flow of 150 m3/S, the windage W2 stands at 680 KW and the air pressure in the vicinity of the air inlet in the air cooler 48 stands at 23 mm Ag. This means that the windage is improved by 17% and the air pressure is elevated by 53%. In short, according to the present invention, the air flow required for cooling can be obtained with a minimum of windage, and the air pressure in the uicinity of the air inlet of the air cooler is greatly elevated.
The second embodiment of the present invention will be explained by referring to Fig. 4. In the first embodiment mentioned above, only one air inlet hole is provided to each chamber. However, in the case of the second embodiment, two air inlet holes 54 and 56 are provided to each chamber in such ~-a manner that they are not aligned in the axial direction. In each chamber formed between the cover plates 12 and 14, an ad~acent pair of spider arms 10 and the annular yoke 18, the ' ~
.'. . ' . ~; - ' '~ '' ' ' ~ ' 1~7670 air inlet hole 54 is formed in the cover plate 12 and the air inlet hole 56 in the cover plate 14. The air inlet holes 54 and 56 are arranged at different positions in the circumferential direction so as not be be aligned in the axial direction.
The third embodiment of the present invention will be explained by referring to Fig. 5. In the second embodiment illustrated in Fig. 4, the air inlet hole 54 in the cover plate 12 and the air inlet hole 56 in the cover plate 14 are arranged at the different positions in the circumferential direction. In the case of the third embodiment illustrated in Fig. 5, the air inlet hole 58 in the cover plate 12 and the air inlet hole 60 in the cover plate 14 are arranged at the different positions in the radial direction.
In the second embodiment illustrated in Fig. 4, as well as the third embodiment illustrated in Fig. 5, the air is inhaled from both air inlet holes into each chamber formed by the cover plates 12 and 14, the spider arms 10 and the annular yoke 18. However, since the air inlet holes 54 and 58 in the cover plate 12 and the air inlet holes 56 and 60 in the cover plate 14 are not aligned with each other, being staggered either in the circumferential or the radial direction, the air currents do not collide in the chamber. The formation of eddies or turbulence is thus reduced.
; SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to improve the cooling efficiency in a rotary electric machine by effective ventilation of the machine.
It is another object of this invention to provide a rotor for such a machine having a ventilation structure capable of securing an air flow required for cooling the high temperature portion of the machine with a minimum of windage loss.
- To this end the invention consists of a rotor for a rotary electric machine comprising: (a) a rotatable shaft, (b) radially projecting spider arms secured to said rotatable shaft, (c) an annular yoke having ducts extending in a radial direction, said yoke being mechanically coupled to radially outer ends of the spider -1'~)87670 arms, (d) cover plates defining a chamber between each pair of spider arms and an inner periphery of said annular yoke while retaining a gap between said inner periphery and outer peripheries of said cover plates, each of said cover plates having an air inlet hole through which air is drawn into the chamber by rotation of said spider arms, and (e) magnetic poles projecting from an outer periphery of said annular yoke, (f) characterized in that the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a longitudinal, partially sectional view~
of a first embodiment of a rotor having a ventilation structure in accordance with the present invention, and particularly shows the flow of air utilised for cooling during operation of the machine.
Fig. 2 shows a partial plan view of the rotor illustrated in Fig. 1.
Fig. 3 shows a characteristic diagram including a ventilation curve (Hl) and a windage curve (Wl) for a rotary electric machine having a conventional ventilation structure, as well as a ventilation curve (H2) and a windage curve (W2) for a rotary electric machine having a ventilation structure in accordance with the present invention.
Fig. 4 shows a partial plan view of a second embodiment of rotor in accordance with the present invention.
- Fig. 5 shows a partial plan view of a third embodiment of rotor in accordance with the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
In Figs. 1 and 2, the rotary electric machine comprises a rotor 4 mounted on a rotatable shaft 2 and a .
.: ~ . .
1~767t~
stator 8 fixed to a base stand 6. Each of a plurality of spider arms 10 has a predetermined width in both the axial and radial.
directions; the radially inner end of each spider arm is fixed to the shaft 2. The outer peripheral ends of the spider arms 10 are connected to an annular yoke 18 by way of cotters 16.
Numerous radial ducts 20 are formed in the annular yoke 18 spaced apart in its axial direction. Cover plates 12 and 14 supported by the spider arms 10 close the openings of the chambers formed between each adjacent pair of spider arms in the axial direction. A predetermined gap 22 or 24 is formed between the outer peripheral end of the cover plate 12 or 14 and the inner periphery of the annular yoke 18. At the outer periphery of the annular yoke 18 there are a plurality of projecting magnetic poles 26. On both sides of the projecting magnetic poles 26 there is an end ring 28 which supports both ends of a damper coil provided on the projecting magnetic poles 26. The rotor 4 is composed of the spider arms 10, the cover plates 12 and 14, the annular yoke 18 and the projecting magnetic poles 26.
A stator yoke 30 is provided with numerous ducts 34 in extending the radial direction and face the projecting magnetic poles 26 across a small gap 32. An armature coil 36 is disposed on the outer periphery of the stator yoke 30 facing the projecting magnetic poles 26. The stator yoke 30 is fixed to the base stand 6 by means of a stator frame 38. Two end covers 40 and 42 are mounted on the stator frame 38 so as to cover the stator yoke 30 and the armature coil 36. Formed between the rotor 4 and each of the end covers 40 and 42 are :
gaps 44 and 46 through which cooling air flows into the end -covers 40 and 42. Disposed on the stator frame 38 is an air cooler 48 for cooling the hot air after it has been utilized ~ -- ` 10876'70 for cooling the high temperature portion of the machine.
In respective cover plates 12 and 14, a number of air inlet holes 50 and 52 are disposed. The holes 50 in the plate 12 and the holes 52 in the plate 14 are staggered so as not to be aligned in the axial direction. There is only one air inlet hole 50 or 52 between each ad~acent pair of spider arms 10.
Arrows shown in Fig. 1 represent the flow of air during operation of the rotor 4. Air drawn into the chamber of the rotor 4 from the outside of the machine through the inlet holes 50 and 52 by the fan action of the spider arms 10 passes into the region of the stator 8 through the ducts 20 on one hand, and simultaneously into the end covers 40 and 42 through the gaps 44 and 46 after having passed through the gaps 22 and 24.
Air discharged from the ducts 20 to the gap 32 flows in the stator frame 38 through the ducts 34.
Air admitted into the end covers 40 and 42 flows in the gap 32 due to the fan action of the projecting magnetic poles 26 and then is divided into two groups. One flows in the stator frame 38 through the ducts 34 and the other flows in the stator frame 38 through the end portion of the ~5 armature coil 36.
All the air flowing in these different routes comes together at the stator frame 38 and is then discharged to the outside of the machine, after having been cooled by the air coolers 48 mounted on the stator frame 38.
Since the air inlet hole 50 on the cover plate 12 and the air inlet hole 52 on the cover plate 14 are staggered, air currents admitted into the chamber of the rotor 4 will not ~
collide with each other in the chamber. Thus turbulence is ~ ~ -- 6 - ~
: . - - . ............ - . . .
- . : . . :
10876t70 eliminated or reduced in the chamber of the rotor 4. Air in this chamber can readily flow in the ducts 20 of the annular yoke 18 and out of the gaps 22 and 24 to the outside of the chamber. As a result, a sufficient air flow into the chamber through the air inlet holes 50 and 52 to refrigerate the high temperature portion of the machine is ensured. In addition, the air, once it has passed through the gaps 22 and 24, flows into the end covers 40 and 42 through the gaps 44 and 46 without flowing back into the chamber through the air inlet holes 50 and 52. The air in the end covers 40 and 42 is used to cool the annular yoke 18, the projecting magnetic poles 26, the stator yoke 30 and the armature coil 36. In short, the air drawn into the chamber due to the fan action of the spider arms 10 is virtually 100% used for cooling. Accordingly, cooling of the machine can be achieved without increasing the windage, and this corresponds to a substantial improvement in cooling efficiency.
The action and effect of the present arrangement will now be explained by referring to Fig. 3 which relates to a 225 MVA rotary electric machine to which a ventilation structure in accordance with the present invention has been applied. The ventilation curve Hl and the windage curve Wl show the relationship between the amount of air flow Q(m3/S) and the air pressure H (mm Ag) and the relationship between the amount of air flow Q and the windage W (KW), respectively, in the vicinity of the air inlet of the air cooler 48.when the respective air inlet holes on two cover plates are aligned in the axial direction. On the other hand, the ventilation curve H2 and the windage curve W2 show the relationship between the amount of air flow Q and the air pressure H and the relationship between the amount of air flow Q and the 1~8767~
, windage W, respectively, in the vicinity of the air inlet of the air cooler 48 for a machine having the ventilation structure in accordance with the present invention; i.e.
staggered air inlet holes.
As the result of experiments, it was found that an air flow of at least 150 m3/S is necessary to cool the high temperature portion of the 225 MVA machine. According to Fig. 2, in the oase of a machine having a ventilation structure wherein the air inlet holes are aligned in the axial direction, it was found that, for an air flow of 150 m3/S, the windage Wl corresponds to 820 KW and the air pressure Hl in the vicinity of the air inlet of the air cooler corresponds to 15 mm Ag. On the other hand, for the machine having a ventilation structure wherein the air inlet holes 50 and 52 on the cover plates 12 and 14 are not aligned and for an air flow of 150 m3/S, the windage W2 stands at 680 KW and the air pressure in the vicinity of the air inlet in the air cooler 48 stands at 23 mm Ag. This means that the windage is improved by 17% and the air pressure is elevated by 53%. In short, according to the present invention, the air flow required for cooling can be obtained with a minimum of windage, and the air pressure in the uicinity of the air inlet of the air cooler is greatly elevated.
The second embodiment of the present invention will be explained by referring to Fig. 4. In the first embodiment mentioned above, only one air inlet hole is provided to each chamber. However, in the case of the second embodiment, two air inlet holes 54 and 56 are provided to each chamber in such ~-a manner that they are not aligned in the axial direction. In each chamber formed between the cover plates 12 and 14, an ad~acent pair of spider arms 10 and the annular yoke 18, the ' ~
.'. . ' . ~; - ' '~ '' ' ' ~ ' 1~7670 air inlet hole 54 is formed in the cover plate 12 and the air inlet hole 56 in the cover plate 14. The air inlet holes 54 and 56 are arranged at different positions in the circumferential direction so as not be be aligned in the axial direction.
The third embodiment of the present invention will be explained by referring to Fig. 5. In the second embodiment illustrated in Fig. 4, the air inlet hole 54 in the cover plate 12 and the air inlet hole 56 in the cover plate 14 are arranged at the different positions in the circumferential direction. In the case of the third embodiment illustrated in Fig. 5, the air inlet hole 58 in the cover plate 12 and the air inlet hole 60 in the cover plate 14 are arranged at the different positions in the radial direction.
In the second embodiment illustrated in Fig. 4, as well as the third embodiment illustrated in Fig. 5, the air is inhaled from both air inlet holes into each chamber formed by the cover plates 12 and 14, the spider arms 10 and the annular yoke 18. However, since the air inlet holes 54 and 58 in the cover plate 12 and the air inlet holes 56 and 60 in the cover plate 14 are not aligned with each other, being staggered either in the circumferential or the radial direction, the air currents do not collide in the chamber. The formation of eddies or turbulence is thus reduced.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A rotor for a rotary electric machine comprising:
(a) a rotatable shaft, (b) radially projecting spider arms secured to said rotatable shaft, (c) an annular yoke having ducts extending in a radial direction, said yoke being mechanically coupled to radially outer ends of the spider arms, (d) cover plates defining a chamber between each pair of spider arms and an inner periphery of said annular yoke while retaining a gap between said inner periphery and outer peripheries of said cover plates, each of said cover plates having an air inlet hole through which air is drawn into the chamber by rotation of said spider arms, and (e) magnetic poles projecting from an outer periphery of said annular yoke, (f) characterized in that the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other.
(a) a rotatable shaft, (b) radially projecting spider arms secured to said rotatable shaft, (c) an annular yoke having ducts extending in a radial direction, said yoke being mechanically coupled to radially outer ends of the spider arms, (d) cover plates defining a chamber between each pair of spider arms and an inner periphery of said annular yoke while retaining a gap between said inner periphery and outer peripheries of said cover plates, each of said cover plates having an air inlet hole through which air is drawn into the chamber by rotation of said spider arms, and (e) magnetic poles projecting from an outer periphery of said annular yoke, (f) characterized in that the air inlet holes in the cover plates are out of alignment with each other so that air currents passing through them do not collide with each other.
2. The rotor defined in claim 1, wherein said air inlet holes are staggered in the radial direction.
3. The rotor defined in claim 1, wherein said air inlet holes are staggered in the circumferential direction.
4. The rotor defined in claim 2, wherein the respective air inlet holes in each pair of cover plates open into the same chamber.
5. A rotor for a rotary electric machine comprising (a) a rotatable shaft, (b) radially projecting spider arms secured to said rotatable shaft, (c) an annular yoke having ducts extending in a radial direction, said yoke being mechanically coupled to radially outer ends of the spider arms, (d) cover plates defining a chamber between each pair of spider arms and an inner periphery of said annular yoke while retaining a gap between said inner periphery and outer peripheries of said cover plates, each of said cover plates having an air inlet hole through which air is drawn into the chamber by rotation of said spider arms, and (e) magnetic poles projecting from an outer periphery of said annular yoke, (f) characterized in that a first said chamber has an air inlet hole in a first said cover plate and a second chamber has an air inlet hole in a second said cover plate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP151784/1976 | 1976-12-16 | ||
| JP15178476A JPS5375402A (en) | 1976-12-16 | 1976-12-16 | Rotor of rotary electric machinery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1087670A true CA1087670A (en) | 1980-10-14 |
Family
ID=15526214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA293,064A Expired CA1087670A (en) | 1976-12-16 | 1977-12-14 | Rotor structure for an air-cooled dynamoelectric machine |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5375402A (en) |
| CA (1) | CA1087670A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112332569A (en) * | 2020-10-29 | 2021-02-05 | 佛山科学技术学院 | Rotor structure of brushless DC motor |
-
1976
- 1976-12-16 JP JP15178476A patent/JPS5375402A/en active Pending
-
1977
- 1977-12-14 CA CA293,064A patent/CA1087670A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112332569A (en) * | 2020-10-29 | 2021-02-05 | 佛山科学技术学院 | Rotor structure of brushless DC motor |
| CN112332569B (en) * | 2020-10-29 | 2022-02-25 | 佛山科学技术学院 | Rotor structure of brushless DC motor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5375402A (en) | 1978-07-04 |
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| JPS6137856B2 (en) |
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