WO2014063673A2 - Electric generator for producing electricity in power plants - Google Patents

Abstract

An electric generator for producing electricity in power plants has an excitation winding (3) on the shaft (1). The turns (4) of the excitation winding (3) are each formed of two half-turns (4') which are soldered together at both ends thereof.

Description

 Electric generator for power generation in power plants

The invention relates to an electric generator for power generation in power plants according to the preamble of claim 1; the invention further relates to a method of manufacturing a conductor for the rotor of an electric generator; Finally, the invention relates to a method for refurbishing the conductors for the rotor of an electric generator.

Electric generators for power generation in power plants have a rotor. This rotor initially has a shaft. On this shaft, the two poles of the rotor are arranged. These each have a winding of several coils, each coil in turn consists of several turns. These windings are formed by electrical conductors made of copper, which are embedded in grooves. The conductors between the two winding heads extend parallel to the shaft. In addition to these axial conductors, there are also the ends of the circular, curved, tangential conductors, in which the axis of the shaft defines the center of the circle.

During operation of the generator, an electric current flows through the conductors. These electrical currents are comparatively high and cause a correspondingly high heating. This reduces the life and the mileage. For this reason, the conductors in the rotor are cooled.

Specifically, the excitation winding of generator rotors is cooled with air or hydrogen to dissipate the heat generated by the excitation current loss heat and to avoid overheating of the insulation components. There are 3 important cooling principles, which are usually used (the following sequence corresponds to the increasing effectiveness of the cooling and thus the achievable power densities of the generator):

Variant 1 is an indirect cooling by passing the cooling gas past the narrow sides of the conductors of the winding.

Variant 2 is direct cooling with flow of the cooling gas across the conductor through corresponding radial bores.

Variant 3 is also a direct cooling with flow of the cooling gas along the conductor. For variants 1 and 2, full copper profiles are used for the conductors of the windings. For variant 2, the conductors are additionally provided with radial bores for flowing through the cooling gas. For variant 3 mostly single or double hollow profiles are used.

Preferably, rotor windings are cooled either according to variant 1 or according to variant 2 or according to a combination of variants 1 and 2. Alternatively, the rotor winding is cooled according to variant 3. This allows the use of only one profile type (Volloder waveguide) and thus a minimum number of solder joints in the winding, since no different profile types must be connected together. A minimal number of solder joints is advantageous because solder joints are a mechanical weak point.

However, there are also generator rotors in which the straight, axial part of the conductor of a winding is designed as a solid profile and is mainly cooled according to variant 1 or according to variant 2 or according to a combination of these variants. The curved, tangential part of the conductor, however, is designed as a waveguide, using a cooling according to the variant 3. The two profile types can also have different widths. However, this concept requires a total of 4 solder joints per turn, namely 2 on the drive and non-drive side of the rotor to connect each 2 hollow and solid sections together to form a turn. Due to their geometric position at the transition between axial and tangential conductors, these solder joints are exposed to very high mechanical and thermally induced forces and therefore form a particular weak point.

On this basis, the invention is based on the invention to provide an electric generator for power generation in power plants, in which at a maximum cooling capacity, the conductors of the turns have as few solder joints as possible.

The technical solution is characterized by the features of claim 1.

This creates an electric generator for power generation in power plants, in which the conductors of the windings have only 2 solder joints. The cooling capacity of the cooling gas is in no way limited. The basic idea is that the turns or conductors consist of 2 half-turns or 2 half-conductors, which are connected to each other both mechanically and electrically. The generator according to the invention thus has a generator rotor winding, which can be cooled in accordance with the above-described variants 1 and / or 2 in combination with variant 3. There are 2 different conductor profiles per turn used, which, however, only one Conductor profile type can be produced. By the windings are formed as half-turns, as stated, the number of solder joints per turn can be reduced to 2 solder joints. These two solder joints can be placed in a position with low load.

Preferably, according to the embodiment in claim 2, the ends of the two half-turns or the two half-conductors are soldered together. This method of mechanical and electrical connection has proven itself.

According to the embodiment in claim 3, it is proposed that the two half-turns are C-shaped. The interface with their solder joints lies between the two C-shaped half-turns in the longitudinal center plane of the rotor, d. H. on the apex of the circular tangential ladder. Of course, it is conceivable to place the solder joints to other positions.

According to the embodiment in claim 4, the conductors of the windings in the transverse direction extending cooling channels. This concerns the axial conductors in which the cooling channels extend in bores with respect to the radial direction as bores. This passage of the cooling gas across the conductor in these axial conductor sections provides optimum cooling performance. In addition, the holes for flowing through the cooling gas are easy to introduce into the ladder.

The development according to claim 5 proposes a possibility for the direct cooling with flow through the cooling gas along through the conductor. These cooling channels are intended for the circular tangential conductor.

A preferred constructive solution for this suggests the development according to claim 6. The basic idea is that it is assumed that a solid profile for the conductor. In this solid profile initially open channels are milled, for example in U-shape. In this case, one or more of these channels can be provided. These channels are closed by applying a so-called intermediate insulation on the conductors at the top, so that thereby a cooling gas flow is realized longitudinally through the conductor. This is similar to the previous waveguide. As a result, a running in the longitudinal direction of the conductor cooling channel is created in a technically very simple manner, without having to use a special hollow profile. Because the cooling channels are created by milling out of the flat top of the ladder. Claim 7 proposes as a further technical solution a method for producing a conductor for the rotor of an electric generator for power generation in power plants.

The core idea is that it is assumed that a conductor full profile, which has the same cross-sectional profile in the initial state over the entire length. It is thus assumed that a solid profile with the length of half a turn and with the cross-sectional dimensions of the largest necessary profile cross-section for the head. This is the wider profile of the previously commonly used profile (usually the hollow profile). The solid profile according to the invention is correspondingly reduced in the area in which a narrower profile is required (the earlier narrower profile) by machining in the width. There is thus an adaptation to the desired profile or cross-sectional profile by removing material. At the point where the solder joint between the two different profiles formed a right angle earlier, according to the invention, the conductor is now transformed by suitable methods into a 90 ° bend. The cooling according to the above-described variant 3 in the region of the tangential conductor is - as stated - realized by milling one or more, open at the top channels along the Volleiters. As a result, overall a tangential conductor is created, more or less in the manner of a waveguide, which starts from a standard conductor full profile.

Claim 8 proposes, as a further technical solution, a method for refurbishing the conductors for the rotor of an electric generator for generating electricity in power plants. Thus, it is possible to rehabilitate existing electric generators for power generation in power plants, namely their conductors by the old, above-described conductors are replaced by inventive conductors or turns.

An embodiment of an electric generator for power generation in power plants will be described below with reference to the drawings. In these shows: perspective view of the electric generator

(but without the end caps);

2 shows a detail of the end region of the generator in FIG.

 1, but with only a single turn;

3a is a side view of a half-conductor of the half-turn; Fig. 3b is a plan view of the half-conductor of the half-turn in Fig.

 3a;

Fig. 4a is a perspective view of the winding consisting of two half-turns before the brazing of these half-turns;

Fig. 4b shows the situation in Fig. 4a after the brazing of the two

 Half-turns;

Fig. 5 is a schematic sectional view through the winding.

The electric generator for power generation in power plants, as shown in Fig. 1, has a shaft 1 with rotor 2 located thereon. This rotor 2 is formed by a field winding 3, which define the two poles. The excitation winding 3 consists of several turns 4, these turns 4 each consist of several electrical conductors 5.

The conductors 5 of the windings 4 are designed as C-shaped half-conductors 5 '(FIGS. 3a and 3b). These two half conductors 5 'are joined together to form the overall conductor 5 and are connected to each other at the end via a solder joint 6. The interface between the two half-conductors 5 'of the conductor 5 lies on the longitudinal center plane of the shaft 1. The interface can also be elsewhere. The half-conductors 5 'form in their entirety the half turns 4', which are then connected to the full turn 4.

The special feature is the formation of the conductor 5 or half-conductor 5 'for the windings 4:

It is assumed in the production of the conductor 5 or half-conductor 5 'of a solid profile of copper, in particular with a flat, rectangular cross-section. This solid profile is bent by appropriate mechanical measures to a C-shape, as shown in Figs. 3a and 3b.

The half-conductors 5 'have cooling channels 7 in the straight axial region. These are introduced through slot-like holes in the material.

A second type of cooling channels 8 is provided in the arcuate tangential region of the semiconductors 5 '. The basic principle here is that in the upper-side flat side of the half-conductor 5 'channels are milled, for example, in a U-shape. This can be a or more of these channels may be provided. Specifically, these cooling channels 8 are realized in such a way that the flat sides of the conductors 5 are stacked with the interposition of a flat insulator 9. However, this means that the milled-in channels are closed at the top by the interposed insulator 9, so that a cooling gas flow is realized longitudinally through the conductor 5 in the form of a cooling channel 8.

As stated, in the production of the conductor 5 or half-conductor 5 'is assumed by a solid profile, which has a same cross section in the initial state over the entire length. In the areas where this cross section is too large, there is a corresponding removal of material, so that the desired cross section or the desired profile is created.

wave

 rotor

 Exciter turn turn 'half turn

 ladder

'Half-ladder

 Soldering Cooling channel Cooling channel Isolator

Claims

Claims 1. Electric generator for power generation in power plants,  with a, a shaft (1) having rotor (2) and  with a, on the shaft (1) arranged exciter winding (3),  the excitation winding (3) consisting of several windings (4) and the windings (4) each consisting of a plurality of conductors (5),  characterized ,  that the turns (4) each consist of two half-turns (4 ') which are electrically and mechanically connected to each other at its two corresponding free ends. 2. Electric generator according to the preceding claim,  characterized,  that the ends of the two half-turns (4 ') are soldered together. 3. Electric generator according to one of the preceding claims,  characterized,  that the two half-turns (4 ') are C-shaped. 4. Electric generator according to one of the preceding claims,  characterized,  in that the axial conductor sections of the conductors (5) of the windings (4) have transverse cooling channels (7) in the form of bores. 5. Electric generator according to one of the preceding claims,  characterized,  in that the circular tangential conductors of the conductors (5) of the windings (4) have cooling channels (8) extending in the longitudinal direction of the conductor (5). 6. Electric generator according to claim 5,  characterized,  that the conductors (5) of the windings (4) are formed as flat solid profiles,  that open channels are formed on the flat side of these solid profiles and  that with interposition of a flat insulator (9), the conductor (5) with their Flat sides abut each other while defining the cooling channels (8) between them. 7. A method for producing a conductor (5) for the rotor (2) of an electric generator for power generation in power plants according to one of claims 1 to 6, characterized  that is assumed that a full conductor profile, which has the same cross-sectional profile over the entire length, and  in that, to create the predetermined cross-sectional profile, the conductor full profile is processed in areas by material removal,  wherein this processing is performed after or before bending the conductor (5) into the desired shape. 8. A method of rehabilitating the conductors (5) for the rotor (2) of an electric generator for power generation in power plants,  characterized,  that the existing conductors or turns  be replaced by conductor (5) or windings (4) according to one of claims 1 to 6 or  be replaced by conductors (5) or windings (4), which are made according to claim 7.