CA1238933A - Cooling system with reduced windage loss - Google Patents
Cooling system with reduced windage lossInfo
- Publication number
- CA1238933A CA1238933A CA000470742A CA470742A CA1238933A CA 1238933 A CA1238933 A CA 1238933A CA 000470742 A CA000470742 A CA 000470742A CA 470742 A CA470742 A CA 470742A CA 1238933 A CA1238933 A CA 1238933A
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- stator
- gas
- vanes
- machine
- 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
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/10—Arrangements for cooling or ventilating by gaseous cooling medium flowing in closed circuit, a part of which is external to the machine casing
- H02K9/12—Arrangements for cooling or ventilating by gaseous cooling medium flowing in closed circuit, a part of which is external to the machine casing wherein the cooling medium circulates freely within the casing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Motor Or Generator Cooling System (AREA)
Abstract
IMPROVED COOLING SYSTEM WITH REDUCED WINDAGE LOSS
ABSTRACT OF THE DISCLOSURE
A sealed rotor motor has axially extending ventilation ducts in the poles. A first stationary set of turning vanes is disposed adjacent one end of the rotor in flow communication with the ventilation ducts to provide an initial tangential velocity to coolant gas in the direction of rotor rotation. A
second stationary set of turning vanes is disposed adjacent the opposite end of the rotor in flow communication with the ventilation ducts to receive said cooling gas which has a velocity in the direction of rotation and direct it into a circulation system for cooling and return to the first set of turning vanes. The two sets of vanes reduce the windage loss in the motor.
ABSTRACT OF THE DISCLOSURE
A sealed rotor motor has axially extending ventilation ducts in the poles. A first stationary set of turning vanes is disposed adjacent one end of the rotor in flow communication with the ventilation ducts to provide an initial tangential velocity to coolant gas in the direction of rotor rotation. A
second stationary set of turning vanes is disposed adjacent the opposite end of the rotor in flow communication with the ventilation ducts to receive said cooling gas which has a velocity in the direction of rotation and direct it into a circulation system for cooling and return to the first set of turning vanes. The two sets of vanes reduce the windage loss in the motor.
Description
~L23~3~3~
Case 27~6 IMPROVED COOLING SYSTEM WITH REDUCED WINDAGE LOSS
.
BACKGROUMD OF THE INVENTION
This invention relates to cooling systems for dynamoelectric machines, and in particular it relates to a cooling system for a sealed rotor dynamoelectric machine having reduced windage loss.
This invention is an improvement on United States Patent No. 4,233,533 - Lown, issued November 11, 1~0 and assigned to General Electric Company. In this United States patent there is described a rotor rim-ventilated generator which has at each of the opposite radially extending ends of the rotor, in adjacent stationary structure, a set of turning vanes or pre-swirl vanes. These sets of vanes both direct coolant gas into the rotor structure in such a manner that the vanes provide an initial tangential velocity to the gas to reduce the windage loss. The gas passes in a radial outward direction through passages in the rotor and then the stator.
The gas may then be cooled and is recycled back to the two sets of inlet vanes.
Although the turning or pre-swirl vanes introduce a tangential velocity to the gas entering the rotor and considerably reduce windage loss, nevertheless the gas exits the rotor into the air gap at the rapidly moving periphery of the rotor, passes ~3~93~
Case 2786 through the air gap and then enters passages extending through the stator in a radial direction. There is windage loss as the gas moves in a generally radial direction from the rotor passages through the air gap to the stator passages.
SUMMARY OF THE INVENTION
The present invention further reduces windage loss in a sealed rotor machine by having turning vanes at opposite ends of the rotor, one set of vanes is for directing gas into the rotor in a manner similar to that disclosed in the aforementioned United States Patent No. 4,233,533, and the other set of vanes for directing gas from the rotor into adjacent stationary structure for circulation.
Preferably each of the opposite generally planar walls of the rotor have an annular opening adjacent a coolant slot. The slot at one end is for introducing a coolant gas and the slot at the opposite end i9 for removing or withdrawing the coolant gas. A plurality of spaced turning vanes is mounted in each slot between annular walls. The vanes in the slot which introduces the coolant gas are disposed to turn or direct the gas in the direction of rotation of the rotor. The vanes in the slot which withdraw the coolant gas are disposed to receive the coolant gas as it moves generally in the direction of rotor rotation and to turn the gas so it moves in a yenerally axial direction. The rotor is provided with a plurality of spaced axially extending passages, the slots for introducing and withdrawing the coolant gas change the direction of gas flow from an axial direction towards the direction of rotor rotation to reduce windage loss, the coolant gas passes through the axially extending rotor passages, and the vanes in the slot which withdraws the coolant gas changes the direction of gas flow from a direction tending to follow rotor Case 2786 rotation to an axial direction, further reducing windage loss.
It is therefore an object of the invention to provide an improved arrangement for reducing windage loss in a sealed rotor dynamoelectric machine.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a radial cross-section of a sealed rotor dynamoelectric machine according to the invention, and Fig. 2 is a sectional view taken along lines 2-2 of Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to Figure 1, there is shown a cross-sectional view of a portion of a vertically mounted dynamoelectric machine 10 having a rotor 11 and a stator 12. While the dynamoelectric machine 10 is shown having a vertical shaft (such as is normally used in a hydrogenerator), the invention may also be used with horizontal shaft machines. An air gap 14 separates the structures of the rotor 11 and the stator 12. The rotor 11 i9 attached to a rotatable shaft 15 which is mounted in a bearing structure (not shown) to permit rotation of the shaft 15 with rotor 11. A hub member 16 is keyed or otherwise suitably secured to shaft 15. Radially extending support plates 17 extend from hub member 16 to rotor core structure 18. End plates 20 and 20a are on opposite ends of the rotor and each end plate has a respective sealing lip 21 and 21a to help confine the flow of cooling gas. Laminations 22 which comprise the rotor core carry poles 28 which have axially extending ventilation ducts or cooling ducts 23. The ducts normally extend between adjacent poles, but the ducts could be formed within a respective pole.
Adjacent one end of ventilation duct 23 is a slot defined by walls 24 and 25. Mounted between the 8~3 Case 2786 walls 24 and 25, and spaced apart around the slot, are turning vanes 26. Adjacent the other end of ventilation duct 23 is a second slot defined by walls 24a and 25a Mounted between the walls 24a and 25a, and spaced apart around the slot, are turning vanes 26a. A
lip 27, mounted at the outer edge of the rotor, opposite lip 21, helps to confine the gas flow as it leaves the slot defined by walls 24 and 25. Similarly a lip 27a, mounted at the outer edge of the rotor 11 and opposite lip 21a helps to confine the gas flow as it enters the slot defined by walls 24a and 25a.
A housing 30 extends from wall 25 around the dynamoelectric machine 10 to join wall 25a, and with a spaced inner housing 31 defines a circulation path 32 for the coolant gas.
The walls 24 and 25 and the walls 24a and 25a extend annularly around the rotor so that the respective slot defined by the walls extends annularly around the rotor. However, the housing 30 and inner housing 31 need not extend all the way around machine 10. Housing 30 and inner housing 31 are conveniently in the form of a duct which extends between walls 24,25 and walls 24a, 25a. In other words, the coolant path 32 is conveniently a duct and preferably there are a plurality o-f such ducts spaced around machine 10. A motor driven fan 33 moves the coolant gas through circulation path 32, through vanes 26, through ventilation ducts 23, through vanes 26a, back to circulation path 32, and fan 33. A
cooler 34 may be mounted in circulation path 32 to remove heat from the coolant gas.
Referring for the moment to Figure 2, there is shown a cross-sectional view with vanes 26 shown directing gas in the direction of rotation of the rotor (the direction of rotation is indicated by arrow 35), and vanes 26a are shown receiving yas ;393~
Case 2786 moving from the direction of rotation of the rotor.
The rotor i9 represented in Figure 2 by po1es 28 with ventilation ducts 23 between adjacent poles 28. It will be apparent that if the direction of rotation of the rotor should be reversed, all that is necessary to adapt the invention to reverse rotation is to reverse the direction of flow of the cooling gas. There is no need to alter the vanes or change their position.
Referring again to Figure 1, the core 36 of stator 12 has radially extending ventilation passages 37. Conductors extend through the stator core 36 and the end turns 38 of the conductors are schematically represented. A housing 40 extends from the stator forming a chamber 41. A cooler 42 is mounted in housing 40 so that a coolant gas which has passed through the passages 37 will pick up heat generated in the stator core 36, pass into chamber 41, and have heat removed as the gas passes through cooler 42. A wall 43 extends around the stator defining a plenum chamber 44. Motor driven fans 45 and 46 are mounted in openings in respective walls 47 and 48 to move the coolant gas Erom the plenum chamber 44 into chambers 50 and 51 where the coolant gas passes over end turns 38 and into air gap 14.
It will be seen that there is a circulation of a coolant gas provided to cool the stator and another to cool the rotor. The windage loss which would otherwise be increased in the circulation of coolant gas through the rotor is reduced, according to the invention, by two sets of vanes. One set at the inlet to the rotor and the other at the outlet. It isl however, not necessary to have two completely separate circulation systems to obtain the advantages of the invention. The invention may be used in any dynamoelectric machine whare a coolant gas is introduced to a rotating component and removed from a Case 27~6 rotating component.
It is preferable, to keep losses to a minimum in the circulation path, to have the corners of the housing curved as indicated. It is also preferable that the vanes havP the configuration of a circular arc or other aerodynamic shape. Because the sets of vanes are similar and because the flow of coolant gas is easily reversed, there is no difficulty in using the invention in a d~namoelectric machine that is reversible.
It is believed that the invention and its operation will be clear and that no further description is required.
Case 27~6 IMPROVED COOLING SYSTEM WITH REDUCED WINDAGE LOSS
.
BACKGROUMD OF THE INVENTION
This invention relates to cooling systems for dynamoelectric machines, and in particular it relates to a cooling system for a sealed rotor dynamoelectric machine having reduced windage loss.
This invention is an improvement on United States Patent No. 4,233,533 - Lown, issued November 11, 1~0 and assigned to General Electric Company. In this United States patent there is described a rotor rim-ventilated generator which has at each of the opposite radially extending ends of the rotor, in adjacent stationary structure, a set of turning vanes or pre-swirl vanes. These sets of vanes both direct coolant gas into the rotor structure in such a manner that the vanes provide an initial tangential velocity to the gas to reduce the windage loss. The gas passes in a radial outward direction through passages in the rotor and then the stator.
The gas may then be cooled and is recycled back to the two sets of inlet vanes.
Although the turning or pre-swirl vanes introduce a tangential velocity to the gas entering the rotor and considerably reduce windage loss, nevertheless the gas exits the rotor into the air gap at the rapidly moving periphery of the rotor, passes ~3~93~
Case 2786 through the air gap and then enters passages extending through the stator in a radial direction. There is windage loss as the gas moves in a generally radial direction from the rotor passages through the air gap to the stator passages.
SUMMARY OF THE INVENTION
The present invention further reduces windage loss in a sealed rotor machine by having turning vanes at opposite ends of the rotor, one set of vanes is for directing gas into the rotor in a manner similar to that disclosed in the aforementioned United States Patent No. 4,233,533, and the other set of vanes for directing gas from the rotor into adjacent stationary structure for circulation.
Preferably each of the opposite generally planar walls of the rotor have an annular opening adjacent a coolant slot. The slot at one end is for introducing a coolant gas and the slot at the opposite end i9 for removing or withdrawing the coolant gas. A plurality of spaced turning vanes is mounted in each slot between annular walls. The vanes in the slot which introduces the coolant gas are disposed to turn or direct the gas in the direction of rotation of the rotor. The vanes in the slot which withdraw the coolant gas are disposed to receive the coolant gas as it moves generally in the direction of rotor rotation and to turn the gas so it moves in a yenerally axial direction. The rotor is provided with a plurality of spaced axially extending passages, the slots for introducing and withdrawing the coolant gas change the direction of gas flow from an axial direction towards the direction of rotor rotation to reduce windage loss, the coolant gas passes through the axially extending rotor passages, and the vanes in the slot which withdraws the coolant gas changes the direction of gas flow from a direction tending to follow rotor Case 2786 rotation to an axial direction, further reducing windage loss.
It is therefore an object of the invention to provide an improved arrangement for reducing windage loss in a sealed rotor dynamoelectric machine.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a radial cross-section of a sealed rotor dynamoelectric machine according to the invention, and Fig. 2 is a sectional view taken along lines 2-2 of Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to Figure 1, there is shown a cross-sectional view of a portion of a vertically mounted dynamoelectric machine 10 having a rotor 11 and a stator 12. While the dynamoelectric machine 10 is shown having a vertical shaft (such as is normally used in a hydrogenerator), the invention may also be used with horizontal shaft machines. An air gap 14 separates the structures of the rotor 11 and the stator 12. The rotor 11 i9 attached to a rotatable shaft 15 which is mounted in a bearing structure (not shown) to permit rotation of the shaft 15 with rotor 11. A hub member 16 is keyed or otherwise suitably secured to shaft 15. Radially extending support plates 17 extend from hub member 16 to rotor core structure 18. End plates 20 and 20a are on opposite ends of the rotor and each end plate has a respective sealing lip 21 and 21a to help confine the flow of cooling gas. Laminations 22 which comprise the rotor core carry poles 28 which have axially extending ventilation ducts or cooling ducts 23. The ducts normally extend between adjacent poles, but the ducts could be formed within a respective pole.
Adjacent one end of ventilation duct 23 is a slot defined by walls 24 and 25. Mounted between the 8~3 Case 2786 walls 24 and 25, and spaced apart around the slot, are turning vanes 26. Adjacent the other end of ventilation duct 23 is a second slot defined by walls 24a and 25a Mounted between the walls 24a and 25a, and spaced apart around the slot, are turning vanes 26a. A
lip 27, mounted at the outer edge of the rotor, opposite lip 21, helps to confine the gas flow as it leaves the slot defined by walls 24 and 25. Similarly a lip 27a, mounted at the outer edge of the rotor 11 and opposite lip 21a helps to confine the gas flow as it enters the slot defined by walls 24a and 25a.
A housing 30 extends from wall 25 around the dynamoelectric machine 10 to join wall 25a, and with a spaced inner housing 31 defines a circulation path 32 for the coolant gas.
The walls 24 and 25 and the walls 24a and 25a extend annularly around the rotor so that the respective slot defined by the walls extends annularly around the rotor. However, the housing 30 and inner housing 31 need not extend all the way around machine 10. Housing 30 and inner housing 31 are conveniently in the form of a duct which extends between walls 24,25 and walls 24a, 25a. In other words, the coolant path 32 is conveniently a duct and preferably there are a plurality o-f such ducts spaced around machine 10. A motor driven fan 33 moves the coolant gas through circulation path 32, through vanes 26, through ventilation ducts 23, through vanes 26a, back to circulation path 32, and fan 33. A
cooler 34 may be mounted in circulation path 32 to remove heat from the coolant gas.
Referring for the moment to Figure 2, there is shown a cross-sectional view with vanes 26 shown directing gas in the direction of rotation of the rotor (the direction of rotation is indicated by arrow 35), and vanes 26a are shown receiving yas ;393~
Case 2786 moving from the direction of rotation of the rotor.
The rotor i9 represented in Figure 2 by po1es 28 with ventilation ducts 23 between adjacent poles 28. It will be apparent that if the direction of rotation of the rotor should be reversed, all that is necessary to adapt the invention to reverse rotation is to reverse the direction of flow of the cooling gas. There is no need to alter the vanes or change their position.
Referring again to Figure 1, the core 36 of stator 12 has radially extending ventilation passages 37. Conductors extend through the stator core 36 and the end turns 38 of the conductors are schematically represented. A housing 40 extends from the stator forming a chamber 41. A cooler 42 is mounted in housing 40 so that a coolant gas which has passed through the passages 37 will pick up heat generated in the stator core 36, pass into chamber 41, and have heat removed as the gas passes through cooler 42. A wall 43 extends around the stator defining a plenum chamber 44. Motor driven fans 45 and 46 are mounted in openings in respective walls 47 and 48 to move the coolant gas Erom the plenum chamber 44 into chambers 50 and 51 where the coolant gas passes over end turns 38 and into air gap 14.
It will be seen that there is a circulation of a coolant gas provided to cool the stator and another to cool the rotor. The windage loss which would otherwise be increased in the circulation of coolant gas through the rotor is reduced, according to the invention, by two sets of vanes. One set at the inlet to the rotor and the other at the outlet. It isl however, not necessary to have two completely separate circulation systems to obtain the advantages of the invention. The invention may be used in any dynamoelectric machine whare a coolant gas is introduced to a rotating component and removed from a Case 27~6 rotating component.
It is preferable, to keep losses to a minimum in the circulation path, to have the corners of the housing curved as indicated. It is also preferable that the vanes havP the configuration of a circular arc or other aerodynamic shape. Because the sets of vanes are similar and because the flow of coolant gas is easily reversed, there is no difficulty in using the invention in a d~namoelectric machine that is reversible.
It is believed that the invention and its operation will be clear and that no further description is required.
Claims (9)
1. A sealed rotor dynamoelectric machine comprising a stator member, a rotor member mounted concentrically with said stator member for rotation within said stator member on an axially extending shaft, said rotor having spaced apart radially extending first and second ends and a plurality of peripherally located poles each extending between said first and second ends, a plurality of spaced apart ventilation ducts each extending between said first and second ends in a substantially axial direction, first means disposed adjacent said first end for admitting cooling gas flow to said rotor and turning said gas flow in the direction of rotor rotation, and second means disposed adjacent said second end for receiving cooling gas flow from said rotor and turning said gas flow from the direction of rotor rotation, said first and second means being in flow communication with said ventilation ducts.
2. A machine as defined in Claim 1 in which said first means is a first set of spaced apart turning vanes.
3. A machine as defined in Claim 2 in which said second means is a second set of spaced apart turning vanes.
4. A machine as defined in Claim 3 in which the vanes comprising said first and second set of turning vanes each has a similar configuration of a curved aerodynamic shape.
5. A sealed rotor dynamoelectric machine comprising a stator, a rotor mounted concentrically within said stator for rotation within said stator on an axially extending shaft, said rotor and stator defining an air gap therebetween, said rotor having a rotor core and axially spaced apart and radially extending first and second ends, a plurality of peripherally located pole members on said rotor between said first and second ends, a plurality of spaced apart ventilation ducts each extending between said first and second ends with first openings in said first end and second openings in said second end to provide passages for the flow of a coolant gas to remove heat from said pole members and adjacent rotor core, a housing extending around said stator and having an annular inlet slot adjacent said first end of said rotor opposite said first openings of said ventilation ducts and an annular outlet slot adjacent said second end of said rotor opposite said second openings, said housing forming a passage for coolant gas between said outlet slot and said inlet slot, a first set of turning vanes mounted in said inlet slot to direct gas from said passage in the direction of rotor rotation, a second set of turning vanes mounted in said outlet slot to receive gas tending to move with said rotor on the direction of rotor rotation and turn it in a generally axial direction, and fan means mounted in said passage for moving a coolant gas from said outlet slot to said inlet slot and through said ventilation ducts.
6. A machine as defined in Claim 5 in which the vanes of said first and second set of turning vanes have a cross-section which is generally that of a portion of a circle.
7. A machine as defined in Claim 6 in which said fan means is reversible for reversing the direction of flow of said coolant gas when the direction of rotor rotation is reversed.
8. A machine as defined in Claim 7 and further comprising cooling means mounted to said housing within said passage.
9. A machine as defined in Claim 7 in which said stator has radially extending cooling ducts
9. A machine as defined in Claim 7 in which said stator has radially extending cooling ducts
Claim 9 continued:
therethrough, and further comprising an inner housing having a first portion extending from said stator and defining a chamber for receiving coolant gas which has passed through said cooling ducts, and inner housing also having a second portion around said first portion defining a plenum chamber communicating with said chamber and with said air gap, and fan means for circulating coolant gas from said plenum chamber, through said air gap and cooling ducts into said chamber and then to said plenum chamber.
therethrough, and further comprising an inner housing having a first portion extending from said stator and defining a chamber for receiving coolant gas which has passed through said cooling ducts, and inner housing also having a second portion around said first portion defining a plenum chamber communicating with said chamber and with said air gap, and fan means for circulating coolant gas from said plenum chamber, through said air gap and cooling ducts into said chamber and then to said plenum chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470742A CA1238933A (en) | 1984-12-20 | 1984-12-20 | Cooling system with reduced windage loss |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000470742A CA1238933A (en) | 1984-12-20 | 1984-12-20 | Cooling system with reduced windage loss |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238933A true CA1238933A (en) | 1988-07-05 |
Family
ID=4129424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470742A Expired CA1238933A (en) | 1984-12-20 | 1984-12-20 | Cooling system with reduced windage loss |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1238933A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5065058A (en) * | 1988-12-22 | 1991-11-12 | General Electric Canada Inc. | Shroud for dynamoelectric machine |
| US6552452B2 (en) | 2000-10-26 | 2003-04-22 | General Electric Canada Inc. | Dynamoelectric machine rotor ventilation |
-
1984
- 1984-12-20 CA CA000470742A patent/CA1238933A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5065058A (en) * | 1988-12-22 | 1991-11-12 | General Electric Canada Inc. | Shroud for dynamoelectric machine |
| US6552452B2 (en) | 2000-10-26 | 2003-04-22 | General Electric Canada Inc. | Dynamoelectric machine rotor ventilation |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |