JPH09180852A - Method for replacing slip ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable economical repair and improve electrical characteristics and service life of a whole slip ring. SOLUTION: In a method for replacing a slip ring of a synchronization machine, a slip ring on a shaft is first cut and processed in a radius smaller than, in particular, the nominal radius of the slip ring or, more advantageously, in a 30mm or 40mm smaller radius, without removing the slip ring from the shaft to fabricating slip ring bushes 8 and 9. Next, new slip rings 6 and 7 made of high-rigidity Cu-Ni-Be alloy is heated, these slip rings 6 and 7 are engaged on the quench engagement face of the slip ring bushes 8 and 9 from the non- drive side of a machine, and the slip ring face of the engaged new slip rings is machined in a nominal radius (rN).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for updating a slip ring of a synchronous machine.

[0002]

The slip rings of synchronous machines, such as turbogenerators, are usually formed of steel rings arranged in pairs. The slip ring is insulated and shrink-fitted onto the slip ring bushing or directly insulated onto the rotor shaft (Berlin Heidelberg New York 1967).
Currently published by Springer-Verlag, Wiedemann / Kellenberger
Author, "Konstruktion elektrischer Maschinen" 392,393
Page).

The slip rings of high speed rotating machines are forced to wear. Replacing the slip ring is relatively troublesome.

[0004]

The object of the present invention is to provide a method for renewing a slip ring which is easy to implement on the one hand and which, on the other hand, improves the service life and the current transfer characteristics of the slip ring. To provide.

[0005]

According to the present invention, the above problems have been solved by the following method steps. I) both slip rings on the shaft without removing the slip ring from the shaft in order to produce the slip ring bushing, in particular 3 more than the nominal radius of the slip ring.
Machined to a radius of 0 mm to 40 mm smaller, b) heat a new slip ring made of high strength Cu-Ni-Be alloy, then this slip ring from the non-driving side of the machine Fit on the shrink-fitted surface of the prepared slip ring bush, and c) Turn the slip ring surface of the new fitted slip ring to the nominal radius.

[0006]

The method according to the invention offers the possibility of economically renewing the slip ring and further increasing the service life of the (new) slip ring. This is because the slip ring has, in addition to a large current carrying capacity, improved running characteristics.

Further, the present invention provides the following advantages. That is, the current transmission loss is reduced and the brush life is extended.

The load capacity of the brush is increased. Therefore, the number of brushes required per polarity is reduced. by this,
Brush consumption is further reduced. This also increases the slip ring surface not covered by the carbon brush. This allows the slip ring to be cooled well and the slip ring temperature to be lowered. This further improves the operating characteristics of the slip ring.

When the slip ring is operated in a closed cooling circuit, filter contamination is reduced and thus filter life is increased due to the reduced carbon consumption.
Furthermore, due to the reduction of the total loss, the exhaust temperature is reduced and thus the recooling output is also reduced.

When installed in existing equipment, the present invention guarantees the required excitation current as high as possible.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Two slip rings 1 and 2 made of steel are insulated and fixed to a shaft 5 by interposing insulating films 3 and 4 on a shaft end NS on the non-driving side of a turbo generator. For example, it is shrink-fitted. The electrical connection to the excitation lead pin located in the shaft hole is omitted for clarity of the drawing, for example the Wied mentioned at the beginning.
It belongs to the known art as is clear from the book of emann / Kellenberger. Such slip rings are subject to wear and must be replaced at regular intervals. For this reason, slip rings 1 and 2 are conventionally used.
Was heated to a few hundred degrees Celsius and then withdrawn in the direction of the shaft end NS. Before putting on a new slip ring,
The insulating films 3 and 4 that are damaged during extraction are replaced.

On the other hand, the present invention is to achieve another method.

Attached slip rings 1, 2
Rather than removing the slip ring, this slip ring is replaced by a slip ring 6 or 7 which is newly fitted.
By a thickness (for example, 30 mm) of the slip ring to a radius r smaller than the nominal outer radius r _{N of the} slip ring. The attached slip rings are, so to speak, slip ring bushes 8 for slip rings 6 and 7 to be newly fitted.
Make 9

According to the invention, the newly slipped slip rings 6, 7 are made of a hardenable copper alloy with an alloy additive of Ni or Be. In this case, CH-6
482 Gurtnellen / Uri HOVADUR of Schmelzmetall AG
It is commercially available under the name CuNiBe (data sheet HOVA
DUR CuNiBe (without date) alloy is particularly advantageous. The copper alloy has an alloy additive of about 1.8% Ni and about 0.4% Be. Copper alloys are already in the hardened "normal state", while at the same time having good electrical and thermal conductivity,
Has high hardness and heat resistance. Further, the alloy is
In the form of heat treatment and so-called "special state"
state) ". In this supply form, the alloy has a strength value corresponding to that of steel. On the other hand, the electrical and thermal conductivity is that of copper. Equivalent to sex.

The new slip rings 6, 7 are approximately 200
It is heated to 0 ° C. and fitted over slip ring bushings 8 or 9 (see FIG. 2). Upon cooling, due to the high modulus of elasticity and high yield point of the copper alloy, the best shrink-fit engagement is obtained to withstand all operating loads. The new fitted slip rings 6, 7 are then fitted with a nominal radius r _N
To be turned.

In order to be able to easily push the inner slip ring 7 through the slip ring bushing 8 of the outer slip ring 1, the outer slip ring 1 advantageously has a radius smaller by the dimension δ. The thickness of the slip ring 6 that has been turned and then fitted again is large by the difference dimension δ (see FIG. 2). In this case, the difference dimension δ is 1 mm to 2 mm.

The slip rings of the medium and large turbo generators have an axial width of 200 mm to 400 mm. The narrow ring made of the copper alloy mentioned above (the ring is usually made from the material by forging) is more economical to make than the wide ring, and the narrow ring is easier to handle during assembly. . For this reason, it is advantageous if the (new) slip ring is made up of a number of single rings 6a, 6b or 7a, 7b which fit together, and in FIG. 3 a slip consisting of two single rings. The ring is shown.

In this case as well, the radius r of the outer slip ring bush 8 is made smaller than the inner slip ring bush 9 by the dimension δ, and the thickness of the two single rings 6a, 6b is correspondingly dimensioned. It is advantageous if δ is large.

In the embodiment shown in FIG. 4, the shrink-fitting surfaces of both slip ring bushings 8, 9 and the corresponding shrink-fitting surfaces of the inner peripheral surface of the slip ring 6 or 7 are correspondingly stepped. Is formed. Each radius is r ₁ ,
r ₂ , r ₃ and r ₄ , in which case r ₁ > r in order to be able to cover the inner slip ring 7 via the outer slip ring bushing 8.
_{2> r} 3> _{r 4} are true. With such a step, the slip rings 6 and 7 can be additionally secured in the axial direction and the assembly becomes easy. Because, depending on the step,
This is because an axial stopper at the time of fitting is obtained.

The embodiment of FIG. 4 can also be used for a single ring 6a, 6b or 7a, 7b as shown in FIG. In FIG. 5, the single rings 6a, 6b or 7a, 7b have radii r ₁ , r ₂ , r ₃ and r _{4 respectively.}
Is seated on the stepped shrink-fitting surface with, in this case the tensions r ₁ > r ₂ > r ₃ > r ₄ apply.

Of course, the invention is not limited to the replacement of slip rings that are directly shrink fitted on the rotor shaft. Naturally, the invention also applies in the case of a slip ring device in which the steel slip ring is shrink fitted to a slip ring bush or a pre-shrink fitting ring (see for example the Wiedemann / Kellenberger book mentioned at the beginning, page 392, FIG. 386 or 388). Applicable.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a shaft end on a non-driving side of a turbo generator having two slip rings made of steel.

2 is a longitudinal sectional view of the shaft end on the non-driving side of the turbogenerator according to FIG. 1 after turning the steel slip ring and fitting it with a new slip ring.

3 shows the variant embodiment of FIG. 2 with slip rings each consisting of two single rings.

FIG. 4 is an enlarged view of the variation of FIG. 2 having a stepped shrink fit surface.

FIG. 5 is a book with a slip ring formed from two single rings each having different shrink-fitting surfaces and fixed to the shrink-fitting surface of a steel ring which is stepped in conformity with said shrink-fitting surface. FIG. 1 shows a particularly advantageous embodiment of the invention.

[Explanation of symbols]

 1,2,6,7 Slip ring 3,4 Insulating film 5 Shaft 6a, 6b, 7a, 7b Single ring 8,9 Slip ring bush d Thickness NS Shaft end r radius rN Nominal radius δ Difference size

Claims (5)

[Claims] 1. A method for renewing a slip ring of a synchronous machine, comprising: (a) both slip rings on the shaft without removing the slip ring from the shaft to make a slip ring bush (8, 9); In particular, a new slip ring (6, 7, 6a, 6b, 7a) made of a Cu-Ni-Be alloy of high strength, which is machined to a radius that is preferably 30 mm to 40 mm smaller than the nominal radius of the slip ring, , 7b) and then this slip ring is connected to the non-drive side of the machine (N
From S), the slip ring bushes (8, 9) prepared in step a) above are fitted onto the shrink fitting surfaces, and c) the slip ring surface of the new fitted slip ring is changed to the nominal radius (r _N ). Method for updating a slip ring of a synchronous machine, characterized by turning. 2. In the step a), the non-driving side slip ring (1) is replaced with another slip ring (2).
2. The method according to claim 1, wherein the diameter is smaller than that, preferably by 2 to 3 mm. 3. In the step b), a large number of single rings (6a, 6a) closely contacting each other for each slip ring.
b, 7a, 7b) is used. 4. In said step a), the remaining slip ring bushes (8, 9) have different radii (
r ₁ , r ₂ , r ₃ or r ₄ ) is subjected to cutting so that a slip ring (6, 7) to be shrink-fitted is subjected to the cutting process so as to form a stepped shrink-fitted surface. With a stepped inner surface that matches the fitting surface, the outer diameter of the largest shrink fitting surface of the non-driving side slip ring bush (8) is the outer diameter of the smallest shrink fitting surface of the adjacent slip ring bush (9). The method according to claim 2, wherein the diameter is smaller than the diameter. 5. In the step a), the remaining slip ring bushes (8, 9) have different radii (
r _1, as _{r 2, r 3, r 4} ) shrink-fit face which is stepped with a is formed, performs cutting, single pieces ring (6a to be shrink fitted, 6b, 7a, 7b) to An inner surface adapted to the stepped shrink fitting surface, and a maximum shrink fitting surface outer diameter of the slip ring bush (8) on the non-driving side is set to a minimum shrink fitting surface of the adjacent slip ring bush (9). The method according to claim 2, wherein the diameter is smaller than the outer diameter.