JPS59162753A - Lumped rotor of induction machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to a block rotor of an induction machine, particularly an inverter-driven induction machine, in which a round bar is arranged in a drill hole as a conductor of a squirrel cage winding. .

[Prior art and its problems]

In induction machines, in order to reduce slippage and rotor loss during rated operation, it is generally known that a round bar made of an appropriate conductive material is used as a short-circuit winding of the rotor. In block rotors, drilling holes for round rods is easier to machine than, for example, grooves for wedge-shaped rods. In such known squirrel cage windings made of round bars, the bars are kept at a distance from the rotor surface.

In recent years, the stator windings of induction machines are often powered via inverters, the stator current containing very large harmonic components. Such stator currents result in excessive temperature rises on the rotor surface, which in some cases may exceed permissible limits and lead to a reduction in the efficiency of the induction machine.

[Purpose of the invention]

The object of the invention is to achieve attenuation of harmonic currents in the block rotor of an induction machine of the above-mentioned type with as little expense as possible.

[Summary of the invention]

This purpose is to provide a block rotor for an induction machine based on this invention, in which the cylindrical rotor surface is made by turning the rotor core together with the round bar conductor, so that the surface of the round bar and the block rotor are alternately formed along the circumference. This is achieved by making the height of the remaining round bar in the rotor radial direction smaller than the diameter of the round bar but larger than the radius of the round bar. By doing this, a sufficiently large portion of the rotor surface is constructed of electrically conductive material, thereby avoiding unacceptably large temperature increases that would otherwise be caused by harmonics in the stator current. Such a structure can be obtained by simply turning a block rotor into which round rods are inserted, so that the additional expense in manufacturing the rotor is small. The height of the remaining bar in the rotor radial direction is selected in such a way that the secure retention of the bar in the block rotor against centrifugal loads is not impaired.

Such a block rotor of an induction machine is manufactured by first drilling a drill hole to accommodate a round bar placed on a diameter sufficiently far from the cylindrical rotor surface before turning, and then inserting the round bar into this drill hole. and then fabricated by turning the block rotor core together with the round bar until the rotor radial height of the remaining round bar is smaller than the diameter of the round bar but larger than the radius of the round bar. It's good. In this way, first of all, the drill holes for accommodating the round rods can be machined at a sufficient distance from the rotor surface, similar to the well-known ordinary squirrel cage windings using round rods. The advantage is that the drill is given a resistance that is as uniform as possible in all directions along its circumference and that deflection of the drill hole is avoided even when the block rotor is relatively long. After inserting the round rod, the block rotor core is then turned together with the round rod until the height of the round rod in the rotor radial direction reaches the desired value (less than the diameter of the tip rod, but larger than the radius of the round rod), thus Alternating surfaces along the rotor surface are obtained consisting of the material of the block rotor core and the conductive material of the round rods.

[Embodiments of the invention]

Next, the present invention will be explained in detail with reference to drawings showing embodiments of a block rotor based on the present invention.

FIG. 1 is a partial sectional view after turning of a block rotor of an induction machine driven by an inverter. ing. The round bar 2 is arranged such that a cylindrical rotor surface 3 is assembled alternately along the circumference from a surface 4 of the block rotor core 1 and a surface 5 of the round bar 2, with this surface 4 and 5 are made by turning the rotor core 1 together with the round bar 2. In this way, the remaining round bar 20 has a height of 6 in the radial direction of the rotor.
is smaller than the diameter 7 of the round bar, but thicker than the radius of the round bar. Therefore, a sufficiently large part of the rotor surface 3 is made of conductive material, i.e. each surface 5, and the border edges 8 of the surfaces 4 remaining on both sides and towards the center of the round bar, when subjected to a centrifugal load, 2 is sufficient to prevent displacement of the round bar 2, so that the retention of the round bar 2 within the massive rotor core 1 is not compromised.

Such a rotor conducts rotor currents due to harmonic currents in the stator windings with low losses.

FIG. 2 shows the block rotor before turning. Initially, a drill hole 9 for accommodating the round bar 2 was formed in the block rotor core 1, which had a diameter larger than the diameter of the rotor surface 3 after turning. This provides a sufficient spacing 10 between the original rotor surface 11 and the drill hole 9 during drilling, thereby avoiding deflection of the drill hole 9. Then, the round rod 2 is inserted into the drill hole 9. The block rotor core 1 is then turned together with the inserted round rods 2 until the desired diameter of the final rotor 3 is obtained. The height of the remaining round bar 2 in the rotor radial direction is smaller than the diameter of the round bar, but larger than its radius.

〔Effect of the invention〕

In accordance with this invention, in particular, in a block rotor of an induction machine driven by an inverter, the cylindrical rotor surface is formed by turning the rotor core together with the round bar conductor, so that the surface of the round bar is alternately formed along the circumference. and the surface of the blocky rotor core, and the height of the remaining round rod in the rotor radial direction is smaller than the diameter of the round rod, but thicker than the radius of the round rod. Since a sufficiently large portion of the rotor surface is made of conductive material, the harmonic current induced in the rotor by harmonic components contained in the stator current mainly affects the rotor surface portion made of conductive material with low resistance. flow, causing a large rotor loss (attenuation). Therefore, a large temperature rise on the rotor surface is not caused, and a decrease in efficiency of the induction machine is also prevented. In addition, such a structure is simply a round bar. This is obtained by turning a block-shaped rotor into which the rotor is inserted, so there is little additional expense when manufacturing the rotor.At this time, the height of the rotor in the radial direction of the remaining nine It is chosen in such a way that reliable retention of the round rod in the block rotor is avoided.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of an embodiment of the block rotor of an induction machine according to the present invention, and FIG. 2 is a partial sectional view of the block rotor shown in FIG. 1 before turning. In the drawings, 1 is a block rotor core, 2 is a round bar, 3 is a rotor surface, 9 is a drilled hole, and 11 is a rotor surface before turning. % Jヱ人I1s士 Yamaguchi Fl (3'I IO2

Claims (1)

[Claims] 1) In a block rotor of an induction machine, particularly an induction machine of continuous overnight drive, in which a round bar is placed as a conductor of a squirrel cage winding in a drill hole, the cylindrical rotor surface is By turning the rotor core into a round bar conductor, the surface of the round bar and the surface of the block rotor core are assembled alternately along the circumference, and the rotor radial direction of the remaining round bar is Block rotor 02 for an induction machine, characterized in that the height of the block is smaller than the diameter of the round bar, but larger than the radius of the round bar, in the block rotor according to claim 1, the cylinder before turning A drill hole is first drilled to accommodate a round rod placed on a diameter sufficiently far from the rotor surface of the shape, then the round rod is inserted into this drill hole, and then the remaining round rod characterized in that the blocky rotor core ~ is turned together with the round bar (2) until the rotor radial height of the rotor is smaller than the diameter of the round bar and the force/flexure is greater than the radius of the round bar. Block rotor of induction machine.