Prime-mover dynamo plants – Plural prime mover – Plural prime movers with fluid interconnection
Reexamination Certificate
1999-10-29
2001-07-10
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Plural prime mover
Plural prime movers with fluid interconnection
C310S232000, C290S052000
Reexamination Certificate
active
06259166
ABSTRACT:
The present invention relates to a generator with double driving machinery. This application claims priority under 35 U.S.C. §§119 and/or 365 to 198 50 052.1 filed in Germany on Oct. 30, 1998; the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
Generators with double driving machinery are known, for example, from “Allianz Report,” February, 1998, page 72, and are used in power plant installations. The generator is typically arranged in what is called a single-shaft system between a gas turbine and a steam turbine, as shown in FIG. 1.2 of the cited document. The generator also includes a slip ring unit electrically connected with it, which is located on the same shaft as the generator. In such single-shaft systems, static excitation devices are installed starting with an excitation current of greater than 2000 amps, whereby the static excitation devices supply the generator rotor winding via the slip ring unit with an excitation current of up to 7000 amps. Up to an excitation current of about 2000 amps, either static excitation devices or brushless excitation machines may be used on the generator shaft.
At least on one side or on both sides of the generator shaft, the generator is connected via a transmission gear with the gas turbine and the steam turbine. Such a transmission gear in this case functions, for example, as a frequency converter to adapt 60 Hz turbines (speed: 3600 rpm) to 50 Hz generators (speed: 3000 rpm), or as a converter that converts from a supersynchronous to a synchronous speed. In addition, an SSS coupling can be used between the steam turbine and the generator, whereupon a coupling of both machines will only be possible after they reach their operating speed.
It was found that in such conventional single-shaft systems with transmission gears, the performance is limited with respect to the mechanical and electrical design. The slip ring device or the slip ring shaft cannot be constructed with a desired diameter size, since the peripheral speed of the brush face at the slip rings is limited to approximately 80 m/s. Up to 80 m/s, a good contact with the brushes for transmitting the excitation current can be ensured. For a 60 Hz generator with 2-pole design, this limit of 80 m/s is reached with a slip ring diameter of 400 mm. A slip ring diameter of 400 mm permits a slip ring shaft diameter of approximately 290 mm. But the shaft diameter of 290 mm limits the maximum mechanical power transfer to approximately 100 MW turbine power if the shaft is manufactured from a steel suitable for generator rotors. This power transmission limit takes into account both the permanent moments to be transmitted by the shaft, and interference forces, such as missynchronizations and short-circuit cutoff.
Single-shaft systems of the known type require a special mechanical design of the shaft bearing which directly adjoins the slip ring unit. The entire torque of the steam turbine is transmitted via this shaft bearing to the generator, whereby the slip ring unit represents only a comparatively small weight load, and the shaft bearing therefore requires a correspondingly complex design.
In addition, a conventional slip ring shaft has, on one side, a coupling flange that has been worked in one piece from this shaft, and, on the other side, a welded-on or shrunk-on coupling that is attached to the slip ring shaft after the slip rings have been installed. The slip rings cannot be installed on a slip ring shaft over a coupling flange.
SUMMARY OF THE INVENTION
It is an object of the present invention to further develop a generator with double driving machinery of the initially mentioned type, in such a way that greater mechanical power can be transmitted from the driving machines to the generator shaft than is possible with previously known generators.
In particular, an object is to create a generator with double driving machinery in which greater mechanical power can be transmitted on the generator shaft on the side of the slip ring unit, and whereby the slip ring shaft and its bearing can be designed in a simpler manner.
According to the invention, the objects of the invention can be realized by providing a generator with double driving machinery that has between the generator shaft and the slip ring shaft a first gear shaft of a transmission gear, and that a driving machine on the side of the slip ring unit is, via a second gear shaft of the transmission gear, connected with the generator shaft.
It is especially advantageous if the torque transmitted by the driving machine on the side of the slip ring unit is delivered to the generator shaft without mechanical stress on the slip ring shaft. The dimensions of the slip ring shaft and of the slip rings themselves are, therefore, only subject to the electrical conditions for the various peripheral speeds. Furthermore, the slip ring shaft only has a coupling flange on one side, which makes slip rings easier to uninstall and reinstall.
It is particularly advantageous if the transmission gear is designed only for the mechanical torque transmission—and is in no way related to the electrical design of a slip ring unit.
With the transmission gear provided according to the present invention, between the generator and the slip ring unit, it is possible to markedly increase the mechanical power transmitted by a driving machine on the side of the slip ring unit, compared to the state of the art, without mechanically stressing the slip ring shaft.
Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of embodiments, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3585473 (1971-06-01), Huxtable
patent: 3697763 (1972-10-01), Middlebrook
patent: 3799284 (1974-03-01), Heder
patent: 4484083 (1984-11-01), Jefferies
patent: 4769993 (1988-09-01), Kawamura
patent: 4814699 (1989-03-01), Koziel et al.
patent: 4862009 (1989-08-01), King
patent: 5739618 (1998-04-01), Kleinburger et al.
patent: 5886505 (1999-03-01), Giberson
patent: 6098735 (2000-08-01), Sadarangani et al.
“Entwicklung der Getriebe bei zu erwartenden Leistungssteigerungen”,Allianz Report, Feb. 1998, pp. 72-78.
Gard, Manfred, “Kombinierte Gasturbinen-Dampfturbinen-Kraftwerke”,Techn. Mitt. AEG- Telefunken 61, 1971, vol. 3, pp. 149-153.
Asea Brown Boveri AG
Burns Doane Swecker & Mathis L.L.P.
Ponomarenko Nicholas
LandOfFree
Generator with double driving machinery does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Generator with double driving machinery, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Generator with double driving machinery will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2493492