RU2396667C1 - Electrical machine stator - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: stator of turbine generator with gas cooling includes housing (1), core (2). Between packs (3) of the core there located are ventilation channels. In high pressure chamber (4) there arranged are air ducts (5) which are interconnected with low pressure chambers located in the area of front parts of stator winding. Ventilation channels are integrated into groups alternating relative to symmetry plane (15) of stator core. Ventilation channels of group (6) are closed on the core bore side. In the teeth area the spacers are installed with possibility of gas flow shift to the neighbouring channel via through holes (9), in the frame yoke area - with possibility of gas passage in even ventilation channels from high pressure chamber to the teeth area, and in uneven ventilation channels - from teeth area to air ducts. In ventilation channels of group (7) the spacers provide gas passage from high pressure chamber to channel (10) which has output (14) to air gap (12) on low pressure chamber side.

EFFECT: improving the cooling of winding and teeth of stator owing to decreasing gas temperature in the gap between stator and rotor of electrical machine.

1 dwg

Description

The invention relates to electrical engineering, in particular to gas-cooled electric machines, for example, turbogenerators.

The known design and gas cooling system of the stator of an electric machine, described in the invention, “A method of gas cooling of an electric machine and an electric machine” (RF patent No. 2267214, Н02К 9/04, published on 08/20/2005). In the design of the electric machine under consideration, a closed-loop ventilation system is used. The proposed design solves the problem of increasing the cooling intensity of the winding and stator core of an electric machine. The stator core consists of burst packages, between which there are radial ventilation ducts formed by distance spacers. An annular shell forming a channel is fixed on the inner surface of the bore of the stator core. The edges of the annular shell made of non-magnetic material are fixed tightly on both sides. The annular shell covers the radial ventilation channels of the middle part of the core and at least the same number of radial ventilation channels of the extreme parts of the stator core, adjacent on both sides to the middle part of the stator core. The remaining radial ventilation ducts of the extreme parts of the stator core communicate with the air gap between the stator and the rotor of the electric machine.

With this constructive solution, the cooling rate of the middle part of the core and the stator winding is reduced, since the gas flow through this core zone is reduced due to a significant increase in aerodynamic drag for gas passage. The flow of cooling gas must additionally overcome significant resistance for passage from the channel formed by the annular shell into the radial channels.

Closest to the technical nature of the claimed invention is the design described in the invention "Stator of an electric machine" (patent for the invention of the Russian Federation No. 2350006, publ. 20.03.2009, Bull. No. 8). In the present invention, the stator of an electric machine with a gas ventilation system comprises a housing, a core, ducts, low pressure chambers and a high pressure chamber. The low-pressure chambers are located in the area of the frontal parts of the stator winding, and the high-pressure chamber is located in the space between the housing and the core. The core consists of burnt bags with axial through holes made along the height of the teeth, and radial ventilation ducts that communicate with high and low pressure chambers. The ventilation ducts are formed by distance struts that are attached to the burnt core packages. All ventilation ducts are closed on the side of the bore of the stator core. Air ducts are placed in the high-pressure chamber on the outer surface of the core along its entire length in increments of one tooth division, which, on the one hand, communicate with the low-pressure chamber, and on the other hand, with the ventilation ducts of the core. In the area of the teeth of the core, distance spacers are installed to provide a displacement of the cooling gas flow in the axial direction through the through holes made in the burst package along the height of the tooth into the adjacent ventilation duct. In the core yoke zone, distance struts are installed to ensure that the flow of cooling gas from the high pressure chamber passes into the teeth zone through even ventilation channels, and from the teeth zone into air ducts through odd ventilation channels.

The proposed technical solution improves the cooling efficiency of the stator winding and core. The disadvantage of this design is the increase in the temperature of the cooling gas during operation of the electric machine in the gap between the stator and the rotor, since all the ventilation ducts of the core are closed on the bore side and the cooling gas circulates only from the rotor channels in the gap.

The problem to which the invention is directed is to improve the cooling of the stator windings and teeth by reducing the temperature of the cooling gas in the gap between the stator and the rotor during operation of the electric machine.

The specified technical result is achieved due to the fact that the stator of an electric machine with a gas ventilation system contains a housing in which a core with a laid winding is placed, a high-pressure chamber, low-pressure chambers, air ducts and radial ventilation ducts. The low-pressure chambers are located in the area of the frontal parts of the stator winding, and the high-pressure chamber is located in the space between the housing and the core. Air ducts are placed on the outer surface of the core, which, on the one hand, communicate with the low-pressure chamber. The core consists of burst packages, between which there are ventilation ducts. Ventilation ducts are formed by struts. Ventilation channels are combined into groups that alternate with each other relative to the plane of symmetry of the stator core.

One group consists of ventilation ducts that are closed on the side of the core bore. The spacers in these channels in the zone of the teeth are installed with the offset flow of the cooling gas in the axial direction to the adjacent ventilation channel through openings located along the height of the teeth. In the yoke zone, the spacers are installed with the passage of the cooling gas flow in the even ventilation ducts from the high pressure chamber to the tooth zone, and in the odd ventilation channels from the tooth zone to the air ducts.

In another group of ventilation ducts, spacers are installed to allow the passage of cooling gas from the high-pressure chamber to the channel. The channel is made in the form of an annular shell and is fixed on the inner surface of the bore of the stator core. An annular shell covers the exits of the ventilation ducts of this group. The channel has an outlet for cooling gas from the side of the nearest low-pressure chamber.

New in the claimed design is the alternation between each other, relative to the plane of symmetry of the stator core, of two groups of ventilation ducts:

- in one group, the passage of cooling gas through the ventilation ducts of the stator of an electric machine is organized according to the invention described in RF patent No. 2350006;

- in another group of ventilation ducts, the spacers are installed with the passage of cooling gas from the high-pressure chamber to the channel formed by an annular shell fixed on the inner surface of the core bore, tightly closed on only one side, with an exit to the air gap between the stator and the rotor from the nearest low pressure chambers and covering the outlets of these ventilation ducts.

The claimed design uses the advantages of cooling the windings and teeth of the stator core of an electric machine, which is organized according to the invention according to the patent of the Russian Federation No. 2350006, in conjunction with the advantages of cooling, in which the cooling gas from the ventilation channels of the stator goes into the channel on the bore formed by the annular shell, and further into the air gap between the stator and the rotor. In this case, the channel is tightly closed only on one side and has access to the air gap between the stator and the rotor from the side of the low pressure chamber closest to it. The use of such a channel allows us to solve the problem of isolating oncoming gas flows exiting the stator and rotor channels into the air gap between the stator and the rotor. Thus, in the air gap between the stator and the rotor, cooling gas circulates not only from the ventilation ducts of the rotor, but also from the ventilation ducts of the stator. Due to this, a decrease in the temperature of the cooling gas in the gap between the stator and the rotor is achieved.

In General, the invention allows to solve the problem of improving the cooling efficiency of the windings and stator teeth of an electric machine by reducing the temperature of the cooling gas in the air gap between the stator and the rotor during operation of the electric machine.

The drawing shows a longitudinal section of the active zone of the stator of an electric machine for one of the alternation of groups of ventilation channels relative to the plane of symmetry of the stator core.

The stator of the electric machine contains a housing 1, in which the core 2 is placed. The core 2 consists of burdened packets 3 and radial ventilation ducts. In the space between the housing 1 and the core 2, which is the high-pressure chamber 4, air ducts 5 are placed that occupy part of the height of the high-pressure chamber 4. Air ducts 5 are connected by input windows to the surface of the core 2 and communicate with the low-pressure chamber located in the zone of the frontal parts of the winding (not shown in the drawing). The ducts 5 have a length equal to the length of the core 2, and their side walls forming the input windows are placed along the symmetry axes of the adjacent teeth of the core 2 through one tooth division. Between the packages 3 of the core 2 are located radial ventilation ducts, which are formed by distance spacers. Ventilation ducts are grouped into groups 6 and 7.

The ventilation ducts of group 6 communicate with the high-pressure chamber 4 and through ducts 5 with the low-pressure chamber (not shown in the drawing). The ventilation ducts of group 6 are closed from the side of the core bore 2 by tangential struts 8. In the area of the teeth, the distance struts are installed to provide a cooling flow of the cooling gas in the axial direction to the adjacent ventilation duct through the through holes 9, which are distributed along the height of the teeth. In the yoke zone, distance spacers are installed to ensure the passage of cooling gas flow in the even ventilation ducts from the high pressure chamber 4 to the tooth zone, and in the odd ventilation channels from the tooth zone to the air ducts 5. Patent RF invention examples can be found in the invention No. 2350006.

The ventilation ducts of group 7 communicate with the high-pressure chamber 4 and with the duct 10. The duct 10 is an annular shell 11 made of non-magnetic material and fixed to the inner surface of the bore of the core 2. In the electric machine, the duct 10 is located in the air gap 12 between the core 2 and rotor 13. The channel 10 is closed on one side, and on the other hand has an outlet 14 into the air gap 12. The outlet 14 is located on the side of the nearest low-pressure chamber.

Along the length of the stator core 2, the ventilation ducts of groups 6 and 7 alternate with each other with respect to the plane of symmetry 15 of the stator core.

During the operation of the electric machine, the flow of cooling gas from the stator coolers enters the high pressure chamber 4, and from the high pressure chamber 4 passes between the air ducts 5 into the even ventilation ducts of group 6 and into the ventilation ducts of group 7. From the even ventilation ducts of group 6 through axial through holes 9, the cooling gas enters the adjacent (odd) ventilation ducts of group 6. Next, the cooling gas moves through the odd ventilation ducts of group 6 and enters the low-pressure chamber through air ducts 5 ia (not shown in the drawing). And from the ventilation channels of group 7, the cooling gas enters the channel 10 formed by the annular shell 11, and then through the outlet 14 into the air gap 12. From the air gap 12, the cooling gas enters the low pressure chamber closest to the outlet 14 from the channel 10. From the low-pressure chamber, cooling gas enters the stator and rotor coolers.

Claims (1)

The stator of an electric machine with a gas ventilation system, characterized in that it contains a housing in which a core consisting of burdened packages with a winding laid in it is placed, a high pressure chamber located in the space between the housing and the core, low pressure chambers located in zones frontal parts of the stator winding, air ducts located on the outer surface of the stator core and communicating with low-pressure chambers, as well as ventilation ducts, which are formed by remote spores and are located between the core packets, while the ventilation ducts form groups alternating with respect to the plane of symmetry of the stator core, in one of which the ventilation ducts are closed from the side of the core bore, and the distance spacers in the tooth zone are mounted to allow the cooling gas flow to move axially to the adjacent the ventilation duct through openings distributed along the height of the teeth, and in the yoke zone distance spacers are installed to ensure the passage of flow cooling gas in even ventilation ducts from the high pressure chamber to the tooth zone, and in odd ventilation ducts from the tooth zone to air ducts, in another group of ventilation ducts, distance struts are installed to allow the cooling gas to pass from the high pressure chamber to the channel made in the form of a shell, fixed on the inner surface of the core bore and covering the ventilation channels of this group, the channel has an outlet from the side of the nearest low-pressure chamber.