JPS5841202A - Apparatus for supplying electric power to turning shaft - Google Patents

Abstract

PURPOSE:To feed electric power to a turning shaft in a contactless manner and to thereby ensure safe and reliable operation of a steam turbine, by providing a primary and a secondary coils for feeding electric power to a heating means which is inserted into a hollow space formed in a turning shaft of a steam turbine. CONSTITUTION:A heating member 5 is fixed to one end of a rotor 1 of a steam turbine and a heating member fixing means 4 is inserted into the rotor 1. The fixing means 4 is formed in a triple structure consisting of the heating member 5, a heating member fixing section and a heat conductive member 13. Further, a secondary coil 8 for feeding electric power to the heating member 5 is disposed on the side of an inlet opening from which the fixing means 4 is inserted into the rotor 1, so that electric power can be supplied from a primary coil by way of electromagnetic induction without causing any contact with turning parts of the turbine. With such an arrangement, electric power can be supplied to a hollow space in the rotor 1 in a contactless manner and the rotor 1 can be heated from the inside. Thus, since wear of contacts can be eliminated, it is enabled to enhance reliability and safety of operation of the turbine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for supplying electric power to a rotating shaft without contact with the rotating shaft, and in particular, to a rotating shaft most suitable for use in a hollow rotating shaft such as a steam turbine rotating shaft. This invention relates to a power supply device for a shaft.

Conventionally, steam turbine rotors have been heated and cooled unidirectionally from the surface to the inside. For this reason.

When a steam turbine suddenly starts, stops, or changes in load, the temperature difference between the rotor surface and the inside becomes large, and operation has to be limited by the thermal stress generated at this time.

Normally, it is necessary to avoid mechanical damage caused by the generation of such thermal stress in steam turbines, so a method has been adopted in which the temperature of the metal parts is gradually increased over a long period of time. This method often has the problem that it takes a long time to reach the rated rotational speed, and that sudden changes must be avoided even when the load fluctuates.

As a method to solve this problem, there is a device that attaches a ring to the coupling part and heats not only the surface of the turbine rotor but also the inside of the rotor by supplying all the electric power to the hollow part inside the rotor using brushes. However, since this method supplies the staining force to the contact between the ring and the brush, it may cause wear of the contact point and short circuits due to contact between the rotor metal part and the brush or ring.

This included problems such as decreased reliability because the movable part was in contact with the L brush (ring). Furthermore, the contact method requires machining of the existing rotor, which causes problems such as generation of stress.

The purpose of the present invention is to eliminate wear and short circuits caused by contact between fixed parts (brushes, etc.) and rotating parts (su/g), which are the drawbacks of the prior art described above, and to alleviate thermal stress generated in the rotating shaft. Another object of the present invention is to provide a device that supplies power to a rotating shaft in a non-contact manner.

The present invention relates to an apparatus for supplying force to the inside of a hollow rotating shaft of a steam turbine without contacting the hollow rotating shaft and controlling the internal temperature, and one embodiment thereof will be described below.

FIG. 1 shows an example in which the present invention is implemented in a steam turbine. A steam turbine rotor 1 having a hollow interior is supported by a bearing portion 2 .

The steam turbine 3 is also connected to a generator via a coupling part 10, and has a heating material fixing device 4 for fixing the heating material 5 from the other end and simultaneously supplying power to the heating material 5. Then, fix it inside the hollow part of the rotor 1.

The heating material fixing device 4 includes a 770 heating material 5. The fixed part 6 and the heat conduction medium 13 have a triple structure, which allows radiation.

The rotor is configured to supply heat to the inner surface of the rotor by conduction. A secondary coil 8 for supplying power to the heating material 5 is attached to the end on the inlet side, and the primary coil 7 is connected to the primary coil fixing part 9 without contacting the rotating part. It is fixed in position and is supplied with power from a power source 12. Figure 2 shows an example of a non-contact power supply system. The secondary output 15 supplied by the primary coil 7 is connected to the heating material 5 through the secondary output supply section 14 .

Here, the structure of the secondary side output supply tfls 14 is hole-shaped in this example, but even if it is sealed to seal the inside of the heating material fixing device 14, its shape may change. However, this does not change the essence of the present invention.

FIG. 3 is a radial sectional view of the rotor l of FIG. 5g2.

As described above, electric power can be supplied to the hollow interior of the rotor l without contact, and heating can be performed from the inside.

The internal surface temperature is determined by installing a temperature sensing element 42 in the heating material fixing device 4.
#) It can be easily obtained by using an FM telemeter or the like or by estimating it from the primary side supply power 11. Next, from the internal surface temperature and external surface temperature,
By determining the common supply power, the primary side supply power 11i is controlled.

The essence of the present invention does not change whether the control amount is a current flow, a voltage with one frequency, or the like.

The present invention does not require any modification of the conventional steam turbine rotor and coupling portion, so it can be easily installed. However, the coupling part for power supply,
Even if other parts are processed or the heating material fixing device is processed, the essence of the present invention is not changed and the present invention can be easily carried out. Further, the same effect can be obtained even if the power supply is changed to DC, three-phase, etc.

By implementing the present invention, the following effects can be obtained.

(1) Reliability and safety are greatly improved because the contacts do not wear out unlike contact methods.

(2) Since there is no need for special machining of the rotating shaft, stress concentration and deterioration due to machining can be avoided.

and can be easily installed.

(3) In the contact method, the multiple contacts shift due to the extension of the turbine rotating shaft, so the short Is? Although there is a high possibility that it will occur, 1
The present invention can prevent short circuit accidents.

(4) To heat from the external and internal surfaces of the rotating shaft,
The thermal stress generated can be significantly reduced, allowing rapid startup and shutdown, and rapid and large load changes.

(5) The life consumption rate t-@ of the turbine rotating shaft can be reduced.

(6) As a result of the above, the reliability and safety of the turbine and the entire plant are improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing a non-contact power supply section, and FIG. 3 is a sectional view of FIG. 2.

Claims (1)

[Claims] 1. A heating means installed in a hollow part within the rotating shaft, a secondary coil on the rotating shaft for feeding the heating means, and a primary coil installed at a position facing the secondary coil. A device for supplying power to a rotating shaft, comprising: a source for fully energizing the next coil;