SU1665469A1 - Rotor of asynchronous motor - Google Patents

Abstract

The invention relates to electrical engineering and can be applied in asynchronous motors with a short-circuited rotor for heavy and medium starting or operating conditions in repeated-short-term and moving modes. The aim of the invention is to improve the starting characteristics. The grooves of the core (C) 1 of the rotor are pear-shaped and reversed: even - narrow side to the outer surface (VP) C, odd - wide side. The core is divided in axial direction into two parts, one of which is rotated relative to the other by one dentate division. Thus, each core of a short-circuited winding (CO) consists of two sections, on one of which is wide, on the other - the narrow side of VP C. In narrow parts of CO, turned to VP C, pear-shaped grooves are made, like CO. Steel bodies are placed in the upper parts of the CO and short-circuiting rings. In the nominal mode, the engine parameters practically do not differ from the serial ones. During start-up, due to the displacement effect, the current passes through the part of the CO facing the VP C. This leads to an increase in starting torque, a decrease in starting current. 1 hp f-ly, 3 ill.

Description

The invention relates to electrical engineering and can be used in asynchronous squirrel-cage electric motors for heavy and medium starting or operating conditions in intermittent and intermittent modes.

The aim of the invention is to improve the starting characteristics.

Figure 1 shows the rotor, the cross section; Figures 2 and 3 show rotor sections along the axis of adjacent rods.

The core 1 consists of two parts 2 and 3, each of which includes one or more packages 4, recruited from electrical steel sheets. In each of the packages 4 there are grooves 5 of a pear-shaped shape, in which the short-circuited winding rods 6 are placed. In each of the parts 2, 3 half of the grooves 5 and, accordingly, of the rods 6 through one, for example odd, face the outer surface of the core 1 with a wide side; Part 3 on "DG

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vermouth relative to part 2 into one notch division so that the odd grooves 5 and the rods 6 of part 3 are aligned with the even grooves 5 and the rods 6 of part 2 and, conversely, the even grooves 5 and rods b of the part are aligned with the odd grooves 5 and the rod 6 of part 2. Thus, each rod 6 consists of two sections 7 and 8. Section 7 faces the outer side of the core 1, shown by dotted line 9. Section 8 faces the outer surface of the core 1, shown by dotted line 10. All rods 6 are connected with short-circuiting rings. 11. In the upper part of the rods 6 and the short-circuiting rings 11, steel bodies 12 are placed, for example, of a spherical shape. On sections 8 of the rods 6 are grooves 13 pear-shaped. Packages A are separated by spacers 14.

The device works as follows.

At the rated rotor speed, the effect of current displacement in rods and steel bodies 12 is negligible and the resistance of the rotor winding is close to nominal. The characteristics of the engine in this mode are practically no worse than those of a conventional engine with pear-shaped rotor slots.

When the engine is started due to the displacement effect, the current in the rods x 6 passes only through the part of the rods 6 close to the outer surface of the core 1. In section 7 the current passes through the wide part of the rod 6 with low resistance, and in section 8 through the narrow part of the rod 6 greater resistance, which increases as a result of the groove 13 being made in the rod 6 to a depth not less than the penetration depth of the current during the start. In addition, the resistance of the rods 6, as well as the short-circuiting rings 11, increases the presence of steel bodies 12 in them, the radius of which is greater than the depth of current penetration into them during start-up. In the nominal mode, the resistance of bodies 12 is comparable to the resistance of the same rod b volumes, but at start-up the current penetration depth into steel bodies 12 becomes less than their radius, the resistance of bodies 12 increases, which leads to an increase in the active resistance of rods 6 and

short-circuiting rings 11. Since during start-up, the current passes through the upper part of the rods 6, bodies 12 are placed there, for example, by centrifugally pouring the rotor winding,

Making the slots 5 and rods b alternately wide and narrowly facing the outer surface of the core 1 made it possible to increase the width of the rotor teeth in their narrowest place. This led

to some decrease in magnetizing current and increase in power factor, in particular at start-up.

The execution of the grooves 13 in the rods b, in addition to increasing the starting torque and

reducing the starting current, direct cooling of the rods 6 was achieved, which allowed in the nominal mode to reduce the temperature of the rods 6 by 5% and the power loss by 1%.

Claims (2)

1. The rotor of an asynchronous motor with a short-circuited winding, containing divided into two parts in the axial to the direction, the laminated core with pear-shaped grooves, in which the rods are placed, and short-circuiting rings, which, in order to improve the starting characteristics, in each parts of the core odd grooves and rods facing wide, and even - narrow side of the outer surface of the core, the second part of the core is rotated relative to the first one per tooth division, in The upper parts of the rods and short-circuiting rings contain steel bodies, mainly spherical. 2. A rotor according to claim 1, characterized in that in the rod facing narrowly to the outer surface of the core, a pear-shaped groove is made with a depth not less than the depth of current penetration in the rod during start-up. 21 6 01 5-B 11 1 Fig.Z