JPH03261340A - Rotor for electric rotating machine - Google Patents

Abstract

PURPOSE:To prevent heating of rotor by fixing a low resistance damper bar, extending in the axial direction, at the rising parts of a plurality of cross slots. CONSTITUTION:A winding 12 is wound in the slot 11 of a rotor 10 and secured by means of a wedge 16. A round damper slot 20a is made in the axial direction in the rising part 13a of the cross slot 13 in the rotor 10, and the damper bar 21a of a damper winding is inserted into the damper slot 20a. The damper winding is made of low resistance material such as copper or aluminum alloy which causes low heat loss due to current and low temperature rise. End of the damper bar 21a is connected with a short circuit board 22 and supported firmly on the outer circumferential section through a supporting ring 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention]' (Industrial Field of Application) The present invention relates to a rotor for a rotating electrical machine, and particularly to a rotor for a rotating electrical machine provided with a plurality of cross slots.

(Prior Art and Problems to be Solved by the Invention) Generally, a rotor 10 of a turbine generator or the like is configured to be long in the axial direction as shown in FIG. Or wrapped. This rotor 10 is
Usually, it rotates at a high speed of several thousand revolutions per minute and generates electricity. Therefore, a plurality of cross slots 13 in the shape of an arc orthogonal to the axial direction are provided at appropriate intervals on the outer circumferential portion of the rotor 10 so as to eliminate unbalanced rotor rigidity. Improvements in cooling technology have improved the steady-state cooling performance of such rotors, resulting in smaller equipment and increased single-machine capacity.

By the way, if a failure or accident such as a line-to-line short circuit or line-to-line ground fault occurs in the equipment or system in the rotor 10, a large unbalanced negative sequence current will flow through the stator to the surface 10a of the rotor 10 and the windings. A current flowing through the wire 12, the retaining ring 14, etc. and having a period twice the power supply frequency is induced in the rotor 10. This unbalanced component due to the negative phase current is absorbed by the damper winding 15 wound within the slot 11 of the rotor 10. but,
Since this damper winding 15 is located inside the slot 11 below the surface 10a of the rotor 10, it does not serve as a current path for the negative phase current, but flows on the surface 10a of the rotor 10. Therefore, this current passes through the complicated surface parts of the slot 11, wedge 16, cross slot 13, etc., and is particularly concentrated in a relatively large amount between the cut-up part 13a of the cross slot 13, which has not been cut, and the slot 11, etc. (See Figure 7)
. Due to this current, the area between the cut-up portion 13a and the slot 11 etc. is locally overheated in a short time. Although this overheating has improved in cooling technology, the rotor 10 is designed in a steady state.
Not only are these surfaces 10a unable to be cooled sufficiently, but there are also problems such as cracks occurring on the surfaces 10a due to overheating.

Furthermore, the area between the cut-up portion 13a and the slot 11, etc. is a place where mechanical centrifugal force and bending stress are high, and if cracks occur due to overheating, there is a problem that the rotor cannot be continuously operated.

In order to solve the above-mentioned problem, the present invention provides a rotor for a rotating electric machine in which a low resistance damper bar is provided at the cut-out portion of the cross slot to prevent overheating of the rotor.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a rotating device that has a slot for winding a winding wire and a plurality of cross slots that are orthogonal to the axial direction at appropriate intervals on the outer periphery. In the child, a low resistance damper bar extending in the axial direction is attached to the cut-up portions of the plurality of cross slots.

(Function) When a failure or accident occurs in a device or system, such as a line-to-line short circuit or a line-to-line ground fault, a large unbalanced current flows on the surface of the rotor, windings, retaining ring, etc. This current tends to concentrate between the cut-up portion of the cross slot and the slot, but this current flows to the low resistance damper bar and prevents heat generation on the surface of the rotor.

(Example) An example of a rotor of a rotating electrical machine of the present invention will be described below with reference to the drawings.

In the drawings, the same parts as in FIGS. 6 and 7 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, a winding 1 is inserted into a slot 11 of a rotor 10.
2 is wound and fixedly supported by a wedge 16. A round damper slot 20a extending in the axial direction is formed in the cut-up portion 13a of the cross slot 13 of the rotor 10 (see FIGS. 4 and 5(a)), and the damper winding is connected to the damper slot 20a. 21 damper bars 21a are inserted. The damper winding 21 is made of a low-resistance material such as copper or aluminum alloy, and is designed to have low heat loss due to current and little temperature rise.

As another method, this damper winding 21 has a trapezoidal damper slot 20b formed in the rotor 10 to adjust the current distribution according to the magnitude of the negative sequence current, and a trapezoidal damper bar 21b is used in the damper slot 20b. (Fig. 5(b)). In this way, the damper slot 20
b and damper bar 21b can be easily processed.

In addition, the round damper slot 20a and the trapezoidal damper slot 20b are arranged so that the damper slot 20a and the trapezoidal damper slot 20b can be
, ') 11) does not jump out.

The end of the damper bar 218 is connected to the shorting plate 22, and the end of the damper bar 21a and the shorting plate 22 are firmly held from the outer periphery by the retaining ring 14.

Note that 23 is a retaining ring keyway provided at the end of the rotor 10, and 23a is a retaining ring key for fixedly supporting the retaining ring 14 on the rotor 10.

In this way, even if there is an unbalanced current due to an abnormal current, the unbalanced current is absorbed by the damper winding 20 and is not affected by the generator. Furthermore, even if this unbalanced current concentrates between the cut-up portion 13a and the slot 13, most of it flows to the damper bar 21a and the rotor 10 between the two
This prevents heat generation on the surface. Therefore, an unbalanced current flows through the rotor 10, preventing a local temperature rise and preventing the rotor 10 from rising in temperature.
0 with confidence.

〔Effect of the invention〕

According to the rotor of the rotating electrical machine of the present invention, since the damper bar extending in the axial direction of the rotor and having low resistance is provided at the cut-out portion of the cross slot, the surface of the rotor is locally heated when abnormal current occurs. You can drive with confidence without having to worry about it.

- slot, 21... damper winding m, 21 a +
21b...damper bar, 22... shorting plate, 23.
・Retaining ring.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the main parts of the rotor of a rotating electrical machine;
The figure is a perspective view of the end structure of a part of the rotor shown in Figure 1,
Fig. 3 is a sectional view of the end structure of the rotor shown in Fig. 1, Fig. 4 is a sectional view showing the main part when damper windings are attached to the rotor, and Fig. 5(a) is a sectional view of the end structure of the rotor shown in Fig. 1. 4 is a partially enlarged view, FIG. 5(b) is a partially enlarged view of another damper winding, FIG. 6 is a perspective view showing the main part of a rotor of a conventional rotating electric machine, and FIG. 7 is a partially enlarged view of another damper winding. FIG.

Claims (1)

[Claims] In a rotor that has slots for winding windings and a plurality of cross slots perpendicular to the axial direction at appropriate intervals on the outer periphery, a rotor that extends in the axial direction at the cut-up portion of the plurality of cross slots. A rotor for a rotating electric machine characterized by having a low-resistance damper bar attached.