SU957358A1 - Electric machine core - Google Patents

Description

(5) CORE ELECTRIC MACHINE

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FIELD OF THE INVENTION The invention relates to electrical engineering, in particular to the design of electrical cores in Korea. Machines of predominantly medium and high power with axial ventilation.

A core core is known, consisting of stamped sheets connected in a bag, the ventilation holes of which form axial conveying channels lj.

This design is characterized by an insufficient degree of turbulization of the air flow in the channel due to the relatively smooth heat-generating surface of the channels - and their great length compared with transverse dimensions, which contributes to the laminarization of the flow and, accordingly, leads to a decrease in the Lortdach tagline along the channel. In addition, the heat-transfer surface is insufficient. Increasing the same transverse dimensions or increasing the number

A series of channels leads to a decrease in the active cross section of the core, an increase in the magnetic resistance and an increase in the dimensions of the core.

Closest to the present invention is the core of the electric machine, consisting of stamped sheets assembled in alternating bags with air vents of different diameters, forming axial channels with a stepped surface 2.

Claims (2)

A disadvantage of the known device is that the magnetic resistance of the packages of core sheets in connection with different diameters of the axial ventilation holes is different, which leads to the appearance of a transverse flow between adjacent packages, i.e. flow perpendicular to the surface of the sheets. This flow is motionless in space (with motionless bands). The rotation of the core in a motionless magnetic flux causes the appearance of eddy currents and additional losses. The purpose of the invention is to reduce losses. The goal is achieved by the fact that each sheet is made with alternating holes with different diameters along the circumference, and the bags are arranged offset by the angular step of the holes. FIG. 1 shows the core, general view; FIG. 2 shows a section along the A-A. The core core is assembled from alternating packets 1 and 2, having different diameters of the air vents and collecting axial ventilation channels 3 with a stepped heat transfer surface of an increased area. The calculated diameter of the axial ventilation duct is equal to the average sign of the diameter of the air vents of the alternating bags in the case of the same width of the bags. In principle, the width of the packages can be different, for example, to provide a greater degree of surface finning, and the distribution of packages with different diameter of holes along the length of the core can be different, for example, to provide a greater degree of finning of the surface of the core channels on the outlet side of the heated cooling air. In order to ensure equality of the magnetic resistances of the backs of the RMA packages 1 and 2, the core core is made up of alternating packages 1 and 2, the pressed sheets of which are made with alternating ventilation openings of different diameters in the same row, collecting axial ventilation channels 3 with stepwise heat dissipation Tsei the surface of the increased area. The device works as follows. During axial ventilation of the machine, the cooling air washes over the internal stepped surface of the axial ventilation ducts. Gradation of the surface throughout the axial channel causes additional turbulence (turbulence of the D-air flow and accordingly leads to an increase in the heat transfer coefficient in the channel. Additionally, an increase in the channel heat-transfer surface due to the addition of subsurfaces due to the gradation without increasing the calculated average channel diameter increases the heat transfer; duct capacity. Thus, due to these two factors, the efficiency of axial ventilation ducts is increased. Lagging device increases the efficiency of heat transfer from the axial channels in the core of the core by increasing the degree of turbulence in the air flow and increasing the heat transfer surface. the surface increases by a factor of 2. An increase in the heat transfer coefficient due to the gradation of the channel surface will also be significant and can be determined by experimentally for konkreggeometricheskih sizes. The invention The core of an electric machine, consisting of stamped sheets assembled in alternating packages, with air vents of different diameters, forming axial channels with a stepped surface, characterized in that, in order to reduce losses, each sheet is made with alternating circumferentially holes of different diameters, and the packages are located offset by the angular step of the holes. Sources of information taken into account in the examination 1. P. S. Sergeev and others. Designing electrical machines. I., Energie, 19b9, p. 2. USSR author's certificate H “77503, cl. H 02 K 1/32, 1972. / / ///// L u ///////. w //// In ////// A C fff.f AA