SU1654935A1 - Rotor of asynchronous motor - Google Patents

Abstract

The invention relates to electrical engineering and can be applied in asynchronous electric motors with a short-circuited rotor for heavy and medium starting or operating conditions in intermittent and moving modes. The purpose of the invention is to improve the starting characteristics. The grooves of the core (C) of the rotor are pear-shaped and face: even - narrow side to the outer surface (VP) C, odd - wide The invention relates to electrical engineering, in particular to asynchronous electric motors with a short-circuited rotor winding. The aim of the invention is to improve the starting characteristics. Figure 1 shows the core of the rotor, the cross section; figure 2 - section aa in figure 1; on fig.Z - section bb in figure 1. by the side. C is divided axially into two parts, one of which is turned relative to the other by one dentate division. So each short-circuited winding rod (S) consists of two sections, one of which is wide, on the other - the narrow side of the CW S. The CO consists of three conductors - copper, pear-shaped, steel-enclosing copper, also pear-shaped, and placed in the upper part of the groove narrow side to the EP C, and aluminum, occupying the rest of the groove. In the nominal mode, the engine parameters practically do not differ from the serial ones. During start-up, as a result of the displacement effect, the current passes through the part of the CO facing the VP C. The resistance of the narrow parts of the CO is quite significant due to the coverage of the copper conductor with steel, which enhances the effect of the displacement. This leads to an increase in the starting torque by 5 ... 15%, a decrease in the starting current to 10%. 3 hp f-ly, 3 ill. The core of the rotor 1 consists of two parts 2 and 3, assembled from electrical steel sheets. In each of the parts 2, 3 there are 4 grooves of a pear shape, each of which contains three conductors that form a short-circuited winding rod: copper conductor 5 of a pear shape, with its narrow side facing the outer surface of the heart (Leo Sp X X) GO

Description

Nick 1, steel conductor 6, which is a pear-shaped tube, covering copper conductor 5, located in the upper part of groove 4 also narrow side to the outer surface of core 1, conductor 7 made of aluminum or its alloy, which occupies the rest of the groove,

Steel conductor 6 can be made wound from a tape, conductor 7 - by pouring. In each of the parts 2, 3 half of the grooves 4 through one, for example, odd, face the wide side to the outer surface of the core 1, the second half of the grooves 4 through one, for example, even, face the narrow side to the outer surface of the core 1, Part 3 is rotated relative to parts 2 into one tooth division in such a way that the odd grooves of the 4 part 3 are aligned with the even grooves of the 4 part 2, and vice versa, the even grooves of the 4 part 3 are aligned with the odd grooves of the 4 part 2. At the same time with the conductors 7, the short-locking rings 8 .

Thus, each rod consists of two sections 9 and 10, Section 9 with a wide side facing the outer surface of the core 1e cht indicated by position 11 of the cross section of the rod, section 10 facing the narrow side of the outer surface of the core 1, indicated by position 12. Shape and section of copper 5 and steel 6 conductors in sections 9 and 10 are unchanged, only the configuration of aluminum conductor 7 is changed.

The wall thickness of the steel conductor tube 6 takes at least 1 mm since the penetration depth of a current of 50 Hz for most grades of steel is less than 1 mm. In this case, in the starting mode, the current passes through only a small part of the cross section of the conductor 6, which contributes to an increase in the starting resistance of the rotor winding and, accordingly, the starting torque.

The height of the copper conductor 5 is not less than the penetration depth of the current in the aluminum conductor 7 at the start. This ensures the maximum starting resistance of the aluminum conductor 7 in section 10. Since the depth of penetration of alternating current into copper is less than

aluminum, the resistance of the copper conductor 5 in the starting mode also increases.

The cross section of the copper conductor 5 is determined from the ratio

0

five

0

five

0

five

0

five

where s

; m sc PM / RF-AI

5 „/ 1Л

rlcro

cross section of copper 5 and steel 6 conductors, respectively; the resistivity of copper 5 and aluminum 7 conductors, respectively.

In this case, the resistance of the copper conductor 5 is not greater than the resistance of the conductor made of aluminum, occupying the same volume as the copper conductor 5 with steel 6. As a result, the resistance of the rotor winding in nominal mode is not greater and the efficiency is not less than that of the serial engine.

The device works as follows.

At the rated rotor speed, the effect of current displacement in conductors 5-7 is negligible and the resistance of the rotor winding is equal to nominal. The characteristics of the engine in this mode are practically not worse than t than the serial engine.

During start-up, due to the effect of current displacement, the resistance of copper conductor 5 increases 1.5 times or more, and steel 6 increases several times. The resistance of aluminum conductor 7 in section 10 increases many times, since it is almost completely located below the depth of current penetration into aluminum. Thus, the starting resistance of the rotor winding is much greater than if it consisted only of aluminum. This leads to an increase in starting torque by 5 ... 15% and a decrease in starting current up to 10%,

Making the grooves 4 alternately facing the wide and narrow sides of the outer surface of the core 1 makes it possible to increase the width of the rotor teeth in their most narrow place and to slightly increase the power factor, especially at the start.

The use of the proposed rotor in asynchronous electric motors allows, in comparison with the prototype, to reduce: starting current up to 10%, time

acceleration - by 4 ... 12%, increase: starting torque by 5 ... 15%, efficiency - by Z., 10%, power factor by 0.5 ... 1%, and also slightly improve engine parameters in nominal mode.

Claims (3)

1. Rotor of an asynchronous electric motor with a short-circuited winding, containing a axially divided laminated core with pear-shaped grooves and rods in them, short-circuiting rings, half of the adjacent grooves facing wide, and the other half with a narrow side to the outer surface of the core, which differs In order to improve the starting characteristics, one part of the core is placed offset from the other part by one tooth division, the grooves are made of the same shape and size, each stage rzhen made up of three conductors, copper, pyriform steel as a tube pyriform covering copper and disposed at the top of the narrow side of the groove to the outer surface of the core, and aluminum five or aluminum alloy placed in the rest of the groove, and the length of the copper and steel conductors is equal to or greater than the sum of the lengths of the aluminum conductor and the double width of the shorting ring. 2. A rotor according to claim 1, characterized in that the wall thickness of the tubular steel conductor is not less than the depth of current penetration into the steel conductor, and the cross section of the copper conductor is determined by the ratio SM Sc / M / pq-pM) five 0 where s m S, rm, pa cross-section of copper and steel conductors, respectively the resistivity of copper and aluminum conductors, respectively. 3. A rotor according to claim 1, characterized in that the height of the copper conductor is not less than the depth of penetration of the current in the aluminum wire when the engine is started. 4 "Rotor according to claim 1, characterized in that the steel conductor is made twisted from a tape. 1 2. 5-5 eight Fig.Z