SU381136A1 - ASYNCHRONOUS MACHINE WITH INTERNAL CASCADE - Google Patents

Description

one

This invention relates to asynchronous machines with an internal cascade.

Known asynchronous machines with an internal cascade, and the other, two windings on the stator and on the rotor, performed on a different number of poles.

A disadvantage of the known machines is the low-tech manufacturing of the rotor windings.

The purpose of the invention is to simplify the manufacture of rotor cascade asynchronous machines.

This goal is achieved by the fact that the rotor winding, made by pouring aluminum in two layers, contains rods extending along the entire rotor package, each of which is connected in series in the end portions of the rotor with two rods of the upper layer having a length of less than half the rotor length , short-circuited in the middle part of the package and shifted to mutually opposite sides with respect to the rod of the lower layer by the part of the greatest pole division.

FIG. 1 shows the rotor in general form, shows cast rings 1, 2 and the length of the rods of the outer layer a; in fig. 2 shows the end of the rotor, shows the rods of the upper layer 3 and the lower layer 4; in fig. 3 is given a section along LL in FIG. one; in fig. 4 - section

in fig. 5 - section along

in FIG. one; B - B in FIG. one.

From the drawings, it follows that the winding can be obtained by pouring rotary slots in liquid aluminum, forming two layers — an outer and an inner one. The rotor rods located in the upper groove layer occupy less than half

length of the rotor package. In the middle part of the rotor package, each of the rotor rods of the upper layer is closed by a corresponding shorting ring, and at the ends it is connected (obtained by pouring liquid

aluminum intermediate parts) with the corresponding core of the lower layer, shifted around the circumference of the rotor by the magnitude of the part (in this case, the third part) pole division of the stator winding with the smallest number of poles. The length of the rotor rods, located in the lower groove layer, is equal to the full length of the rotor steel package. Along the ends, each of these rotor rods of the lower groove layer is connected to two other short rotor rods of the upper groove layer a, located on opposite sides of it (see Fig. 1). Three types of rotor sheets are used for this. This embodiment of the rotor winding

allows it to simultaneously perform the functions of two separate windings for odd-numbered polarities.

As a result of the spatial displacement of the rods of the outer layer relative to the rods of the inner layer, the magnetizing force in each three-rod group of the rotor winding is distributed in such a way that its harmonic composition has 1, 3, 7 ... components.

Consequently, the rotor winding creates magnetic fields with the numbers of the pole pairs P, Zp, 7p, QP, 5p, etc., each of which can induce an EDS stator winding, whose frequency will be proportional to the speed of rotation of the rotor. Such a connection between the input and output frequencies is characteristic of a cascade of two machines or of a single machine with a so-called internal cascade.

The difference between the induction machine proposed here and the known cascade motors is that if the rotary windings in the known cascade machines have to be performed with relatively thin wires with groove and inter-turn insulation, then, with the rotor winding offered by the proposed machine, the rotary slots are filled with liquid aluminum. package.

On the stator, it is proposed to arrange either two separate multiphase windings with the same numbers of poles (in particular, when the ratio of the numbers of pole pairs of windings is three, either nine or fifteen), or one winding that performs the properties of the two windings on a different number of pole pairs ( for example, I, 1 and P2 7).

To eliminate the direct magnetic coupling between the input and output circuits, the stator winding pitch for the smallest number of poles is chosen shortened by an amount inversely proportional to the multiplicity of poles of the output and input circuits.

The proposed induction machine can be used as:

a) asynchronous frequency converter;

b) the main part of the tachometer device for measuring both very low and very high speeds or for oscillography of the mechanical characteristics of an asynchronous short-circuited motor during its take-off run, if the voltage from the output winding part to a greater number of poles is pre-input to the multiphase bridge semiconductor rectifier; Such a tachometer device allows to obtain a minimum frequency of the output voltage pulsation several times higher than the frequency of the power supply network, which allows to significantly improve the accuracy

measurements, especially at very low measured speeds;

B) an asynchronous frequency-controlled electric motor with two-way power supply, etc.

Subject invention

Claims (2)

1. An asynchronous machine with an internal cascade containing two windings on the stator for different numbers of pairs of poles and a squirrel-cage rotor, characterized in that, in order to simplify manufacturing and increase reliability, the rotor winding, made by pouring aluminum in two layers, contains rods running along the entire rotor package, each of which is connected in series in the end portions of the rotor with two rods of the upper layer having a length less than half the length of the rotor, short-circuited in the middle part of the package and displaced in mutually opposite sides relative to the rod of the lower layer to the part of the greatest pole division. 2. An asynchronous machine according to claim 1, characterized in that each group consisting of upper layer rods connected in series with the lower layer rods at one end of the rotor is short-circuited by a separate cast ring. / Fig 2 Aa Fig.Z b- Q Bb Rag 4 Rig 5