RU2485659C2 - Nonsalient pole rotor of synchronous electric machine - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: nonsalient pole rotor of synchronous electric machine contains a shaft with flux core having channels for excitation winding, exiting coils laid in channels of the flux core, rings aligning with axial ventilation channels, retaining rings and banding insulation. In pursuance of the present invention retaining rings and banding insulation are made with tangential-oriented radial slots located along length of retaining rings located in several rows preferably opposite gaps between end parts of exciting coils.

EFFECT: improved cooling of front parts of excitation coils located in channels of the core of nonsalient pole rotor of synchronous electric machine.

3 dwg

Description

The invention relates to the field of electrical engineering.

Implicit pole rotors of a synchronous electric machine are known, where special measures for cooling the frontal parts of the field winding coils are not provided. The heat from the frontal parts of the coils in such rotors is to some extent transferred to the cooling medium through the retaining rings from their outer surface, but mainly flows into the grooved parts of the winding and is transferred to the cooling medium along with the heat released in the grooved part of the rotor winding (see ., for example, E. Videman, V. Kellenberger. Designs of electrical machines. Energy, Leningrad Branch, 1972, p. 116, second paragraph above).

The disadvantage of the design is the low efficiency of use of the material of the field winding of the rotor.

Implicit-pole rotors of synchronous electric machines are known where flow cooling of the frontal parts of the field winding coils is used (see the mentioned monograph, p.116, fig. 3-30a, 3-30b). In these cases, the cooling medium is supplied to the area of the frontal parts of the field winding coils through the axial ventilation channels in the centering rings near the rotor shaft. In the design variant in Figs. 3-30b, the cooling medium washes mainly the lower turns of the field winding coils and is diverted into the gap between the stator core and the rotor of the electric machine through inclined holes in the rotor’s magnetic barrel.

The design drawback is the low cooling efficiency of the frontal parts of the field winding coils.

In the design variant of Figs. 3-30a adopted as a prototype, the cooling medium washes both the lower turns of the field coil coils and the sides of the coils and leaves the chambers of the frontal parts of the field coil coils through radial holes in the retainer rings of the rotor.

The disadvantages are that in the area of the frontal parts of the field winding coils, in order to avoid displacement of the coil conductors during operation of the electric machine, the entire coil height is wedged by numerous distance spacers with the sides of the coils forming and the distance spacers themselves of the numerous “chambers” closed from the top with retaining rings, having blown cooling medium the sides of the coils is possible only if radial holes are made in the retaining rings opposite, if not every such "chamber", then at least a large number of them, which is extremely difficult, especially considering that the corresponding holes must be made in the bandage insulation.

Radial holes in the retaining rings are powerful concentrators of mechanical stresses in the rings, which can make it difficult to make retaining rings with the necessary margin of mechanical strength.

The task of the invention is to improve the cooling of the frontal parts of the coils of the excitation winding of the implicit pole rotor of a synchronous electric machine.

The technical result is achieved by the fact that in an implicit pole rotor of a synchronous electric machine containing a shaft with a magnetically conductive core (barrel) of the rotor, field winding coils laid in the grooves of the magnetically conductive core (barrel) of the rotor, rings centering with axial ventilation channels in the area of their inner diameter, rings bandage as well as bandage isolation, retaining rings and elements of bandage isolation are made with tangentially oriented radial slots located along the length of the ring preferably in several rows opposite axial spacing between the end portions of the field winding coils.

The invention is illustrated by drawings, where Fig. 1 shows a longitudinal section, Fig. 2 is a cross section (along A-A in Fig. 1), Fig. 3 is a view of a retaining ring (according to B in Fig. 2).

The implicit pole rotor of a synchronous electric machine comprises a shaft 1 with a magnetically conducting core (barrel) 2, in the grooves of which are placed 3 coils of the field winding. The frontal parts of the coils 3 are protected from destruction by centrifugal forces during operation of the electric machine with retaining rings 4, which are mounted on centering rings 5, having axial ventilation ducts 6 in the area of their inner diameter 6. The retaining rings 4 are made with several rows of tangentially oriented radial slots 7 separated by each other from each other in each row with jumpers 8.

Figure 1 shows an embodiment of an implicit pole rotor of a synchronous electric machine with a discharge ventilation system. The cooling medium (its movement is shown by arrows) from the pressure zone at the outer ends of the centering rings 5 through axial ventilation channels 6 enters the frontal area of the field coil 3 coils, passes under the field coil 3 coils along shaft 1, branches into axial gaps 9 between the end parts of the coils 3 of the field winding, in the axial spaces 10 and 11 between the coils 3 of the field coil and centering rings 5 on one side and between the coils 3 of the field coil and the ends of the magnetically conductive core (barrels) 2 on the other hand, as well as in the intervals 12 between the lateral sides of the rectilinear departures of the coils 3 of the field winding from the magnetically conducting core (barrels) 2. Then through tangentially oriented radial slots 7 in the retaining rings 4 and in the elements of the bandage isolation (in the figure not shown) is ejected from the zones of the frontal parts of the coils 3 of the field winding.

Improving the cooling of the frontal parts of the winding coils is achieved due to the fact that tangentially oriented radial slots 7 in the retaining rings 4 of the present invention provide:

- large total cross-section for the passage of the cooling medium;

- reduced aerodynamic resistance of the zones of the frontal parts of the coils 3 of the field winding;

- increased flow rate of the cooling medium through the zones of the frontal parts of the coils 3;

- intensive blowing of the sides of the coils 3, especially since these radial slots 7 in the retaining rings 4 “open” if not all, then the vast majority of the “chambers” mentioned above, formed by the sides of the coils 3 and the distance spacers between them.

The number of slots 7 in each row, the number of rows of slots 7, the dimensions of the jumpers 8 between the slots 7 in each row, the axial dimensions of the slots 7 (their width) can be chosen constructively and quite arbitrarily. The mechanical strength of the retaining rings 4 is almost always decisive in such designs. It should be noted in this connection that the tangentially oriented radial slots 7 are not powerful stress concentrators, like cylindrical holes in the retaining rings of the prototype rotor. Therefore, mechanical stresses in the retaining rings 4 of the proposed rotor can be provided at a sufficiently low level.

The advantages of the proposed design include the fact that in some cases the retaining rings 4 with tangentially oriented radial slots 7 can be used as fans with blades in the form of jumpers 8, which provide the necessary flow rate of the cooling medium. At the same time, individual fans become unnecessary, which simplifies and reduces the cost of both the implicit pole rotor and the electric machine as a whole.

The claimed invention is used in synchronous machines of the SDP, SDR, TGG-2500 series.

Claims (1)

An implicit pole rotor of a synchronous electric machine, comprising a shaft with a magnetically conducting rotor core (barrel), field winding coils laid in the grooves of the magnetically conducting rotor core (barrel), centering rings with axial ventilation channels in the area of their inner diameter, retaining rings, and also bandage isolation, characterized in that the retaining rings and the elements of the bandage insulation are made with tangentially oriented radial slots located along the length of the rings in several rows of predominantly Significantly opposite the axial gaps between the end parts of the field coil coils.

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