RU2824178C1 - Electrical machine stator - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: stator of electric machine includes core from sheet electrical steel and slots for arrangement of windings. Invention is characterized by the fact that the sheets of electrical steel on the side opposite to the slots have protrusions directly in contact with the coolant. At the same time tops of protrusions are connected to each other by bandage tape, threads or other composite material.

EFFECT: higher efficiency of cooling.

5 cl, 14 dwg

Description

The invention relates to the field of electrical engineering, in particular, to electrical machines of wide application. The problem solved by the present invention is to increase the efficiency of cooling of the stator of an electrical machine.

Cooling systems for electrical machines are known in which the coolant is supplied to the copper of the stator and rotor windings. This system is effective, but structurally complex and can be used in the largest electrical machines (A.I. Moskvitin. Direct Cooling of Electrical Machines. - M. Publishing House of the USSR Academy of Sciences, 1962, pp. 10-34).

The design of the asynchronous motor AO-82 is also known (Design of electrical machines. Ed. P.S. Sergeev - M.: Energiya, 1969, pp. 182-184, Fig. 9.9 and 9.9a). This design is accepted as a prototype.

The main disadvantages of the prototype: the heat generated in the stator winding is transferred to the stator core, made of sheet steel, combining with the heat generated in the core, and then this total heat overcomes 2 more obstacles: the connection of the core to the housing and the thermal resistance of the housing, before reaching the coolant (air blowing around the housing).

The purpose of the invention is to increase the energy efficiency of cooling, simplify the design, reduce the weight and dimensions, increase the efficiency and improve the reliability of the electric machine by changing the design of the stator.

The stated goal is achieved by the fact that, unlike the prototype, the last two obstacles are removed: the connection of the core with the housing and the housing, and the core protrusions form ribs that directly contact the coolant.

Fig. 1 shows a sheet 1 of electrical steel with grooves 2 for placing the winding and protrusions 3.

Fig. 2 shows a cross-section of core 4 (shaded), Fig. 3 shows its longitudinal section (along A-A in Fig. 2), and Fig. 4 shows view B in Fig. 3. Section B-B in Fig. 3 corresponds to view in Fig. 2.

The core consists of sheets 1, pressure rings 5 and tie rods 6.

Fig. 5 shows a sheet 7 of electrical steel with openings 8 for tie rods 6 and slots 9, which prevent the magnetic flux from closing around the rods and thus prevent the occurrence of currents in the tie rods. Similar openings are made in the pressure rings. This solution allows the pressure rings to be made according to the profile of sheet 7 and thereby maximally increase the windows in the core for the passage of cooling air in the axial direction, as well as reduce the mass of the rings.

Similarly, sheets 10 for tie rods 6 between the projections can be made with the same holes 8 and slots 9, as shown in Fig. 6.

This type of stud placement in axonometric projections is shown in Fig. 7 (corresponds to the sheet of Fig. 5) and Fig. 7a (corresponds to the sheet of Fig. 6). The arrows in these figures conventionally indicate the direction of movement of air cooling the core.

Figures 1-7a show the simplest version of stator cooling. It can be effective for electric machines located on moving products: on subway cars, electric trains, trains, airplanes and other aircraft, on water transport.

It is also possible to increase the cooling efficiency, for example, by installing a blower fan on the shaft of the electric machine (as shown in the prototype - p. 182, Fig. 9-9) or a separate fan or compressor.

Fig. 8 shows a variant where a cylinder 11 is installed on the surface of projections 3, forming axial channels for the coolant with the projections. This cylinder can be made of aluminum, titanium, steel or other metals and their alloys, as well as composite and other structural materials.

Fig. 9 shows an axonometric projection of the core, and the arrows conventionally indicate the direction of movement of the coolant in the axial channels.

Fig. 10 shows a variant where the tops of the projections 3 are connected to each other by a composite material 12, for example, a bandage tape, carbon or other high-strength threads. In this case, it is possible to impregnate and bake the entire stator with the winding, core, composite bandage with an insulating compound to create a lightweight monolithic high-strength structure.

This design with a pre-glued core and pressure rings made of insulating material, such as fiberglass, can be made without tie rods.

Cooling is carried out similarly to the variant in Fig.9.

Fig. 11 shows a variant where the stator sheet is made with crossbars 13 between the tops of the protrusions in which the tie rods 6 are placed.

In this case, the cellular structure of the core acquires high rigidity.

At present, inverted electric machines are becoming increasingly widespread - with an external rotor in relation to the stator (for example, patent RU 2458446 C1).

For such a design of the electric machine, Fig. 12, 13, 14 shows a sector of the stator sheet 1, in which the slots 2 for the winding are located outside the stator, and the projections 3, blown by the coolant, are inside.

To increase the blowing speed (and, consequently, increase the cooling intensity), a cylinder 11 can be used, which forms axial channels 14 (Fig. 13) with protrusions 3 and sheets 1, blown with coolant using a fan or compressor.

If the cavities of channels 14 are sealed (for example, with a compound that impregnates the stator winding and core), then cooling liquid (water, antifreeze, oil) can be supplied through these channels, which will dramatically increase the cooling efficiency of the stator and the entire electric machine.

The same liquid cooling system can be used for the non-reversible electric machine described earlier (Fig. 1-11).

Fig. 14 shows a variant with jumpers 13 between the tops of the projections 3 - similar to Fig. 11 for a non-reversed electric machine.

Claims (5)

1. A stator of an electric machine having a core made of sheet electrical steel and slots for accommodating windings, characterized in that the sheets of steel on the side opposite the slots have projections that are in direct contact with the coolant, and the tops of the projections are connected to each other by a bandage tape, threads or other composite material. 2. The stator according to item 1, characterized in that pins are placed in the depressions between the projections, which tighten the sheets and form a core together with the sheets and pressure rings. 3. The stator according to item 1, characterized in that the tie rods are placed in projections with holes. 4. The stator according to item 1, characterized in that the slots for the winding are located inside the stator, and the projections in contact with the coolant are located outside. 5. The stator according to item 1, characterized in that the slots for the winding are located on the outside of the stator, and the projections in contact with the coolant are located on the inside.