JPH10225029A - Turbine-generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax the concentration of an eddy current transferring between a damper bar and a solid core in the vicinity of an end section, in the axial direction of the short-sized wedge of a rotor. SOLUTION: A plurality of slots extended in an axial direction are formed to the side face of the solid core of a rotor, and field windings are wound in these slots. A plurality of short-sized wedges 3 for fixing the field windings are inserted successively to the opening section sides of each slot in the axial direction. Conductive damper bars 4 are arranged on the lower sides of a plurality of the short-sized wedges 3 in each slot. A plurality of short-sized wedges 3, the damper bars 4 and the solid core are stuck fast and fixed mutually, and the electrically unified state is also maintained. Corner sections 36 on the damper bar 4 sides at end sections 34 in the axial direction are formed in a shape rounded into a cylindrical surface shape in the short-sized wedges 3. Accordingly, electrical contacts in the vicinity of end sections 34 of the short- sized wedges 3 are made weaker than those in the other sections.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure having a rotor having a massive iron core, in which wedges for fixing field windings in the slots are fitted into openings of a plurality of slots of the massive iron core. In particular, a turbine generator having a structure in which a plurality of short wedges divided in the axial direction are used as wedges, and a conductive damper bar is interposed between the short wedges and the field winding. About the machine.

[0002]

2. Description of the Related Art A conventional turbine generator illustrated in FIG. 3 includes a rotor 2 rotatably supported in a casing 15 and a stator 1 provided around the rotor 2.
And As shown in FIG. 3, the stator 1 of the turbine generator has a field core 10 and a field winding 12.

As shown in FIG. 4, a rotor 2 of the turbine generator has a massive iron core 5 having a substantially cylindrical shape. As shown in FIGS. 4 and 5, a plurality of slots 50 extending in the axial direction are formed on the side surface of the massive iron core 5. As shown in FIG. 5, a field winding 9 is wound in a slot 50 of the massive core 5, and the field winding 9 and the massive core 5 are insulated by a ground insulating layer 8. ing.

As shown in FIGS. 4 and 5, a plurality of short wedges 3 for fixing the field winding 9 are sequentially inserted in the axial direction into the opening side of each slot 50 of the massive iron core 5. Have been.

As shown in FIGS. 5 and 6, each short wedge 3 has a substantially rectangular parallelepiped main body 30 and a pair of left and right protruding portions 32 protruding outward from both lower side surfaces of the main body 30. ing. As shown in FIG. 5, a pair of left and right concave portions 52 corresponding to the both projecting portions 32 of the short wedge 3 are formed in each slot 50 of the massive iron core 5. Further, as shown in FIG. 6, at the axial end portion 34 of the short wedge 3, a lower corner portion 35 (on the side of the damper bar 4) is formed substantially at a right angle.

A short wedge 3 is provided above the field winding 9.
A ground insulating member 6 for maintaining insulation between the side and the side is arranged.

Here, in the turbine generator, when a negative-phase current flows through the stator winding 12 shown in FIG. 3 due to a ground fault or the like, the structure of the massive iron core 5 and the short wedge 3 of the rotor 2 is reduced. An eddy current is induced in the structure, which causes heating of the structure of the rotor 2.

In recent years, in a power generation system using a gas turbine, a thyristor starting system in which a gas turbine is operated as an electric motor when starting the gas turbine has been put into practical use. In this starting method, a turbine generator is used as a variable-speed synchronous motor at the time of starting. That is, by using an inverter as a variable frequency power supply and gradually increasing the frequency of the AC power supply from 0, the rotation speed of the turbine generator (as an electric motor) is increased in synchronization with the power supply frequency.

At this time, the stator winding 12
The current supplied to the device includes a harmonic component that is not synchronized with the rotation speed, in addition to the synchronous frequency component. An eddy current is induced in the rotor 2 by the harmonic components, and the rotor 2
Cause heating of the structure.

Therefore, in order to alleviate the heating due to the eddy current as described above, as shown in FIGS. 5 and 6, in each of the slots 50 of the massive iron core 5, a conductive material is provided below the plurality of short wedges 3. Is disposed.

At the time of high rotation including the rated rotation speed of the turbine generator, the plurality of short wedges 3 and the massive iron core 5 and the damper bar 4 are brought into close contact with each other due to centrifugal force and fixed to each other. Become. However, as described above, in a thyristor-activated turbine generator, unlike a normal generator, there is an operation state in a low rotation speed region. At such a low rotation speed, the centrifugal force is small, and the short wedge 3 and the damper bar 4
Move, and the short wedge 3 and the massive iron core 5 and the damper bar 4 repeatedly contact and separate (non-contact).

In such a state, when an eddy current is induced, pitching occurs on the contact surface between the short wedge 3 and the massive iron core 5 and the damper bar 4. When such pitching occurs every time the turbine generator is started, the contact surfaces of the short wedge 3 and the massive iron core 5 and the damper bar 4 become rough. If the contact surface becomes extremely rough, it may cause vibration or heating with a reverse-phase load during operation as a generator.

In order to suppress the movement of the short wedge 3 and the damper bar 4 in the slot 50 at the time of such low rotation, as shown in FIG. The short wedge 3 and the massive iron core 5 and the damper bar 4 are closely contacted and fixed to each other by means such as interposing a leaf spring 7 between the member 6 and the like. That is,
Regardless of the operating state of the turbine generator, the plurality of short wedges 3, the massive iron core 5, and the damper bar 4 are always in close contact with and fixed to each other, so that they remain electrically integrated.

[0014]

The conventional turbine generator as described above has the following problems. That is, since the plurality of short wedges 3 and the massive iron core 5 and the damper bar 4 always keep a state of being electrically integrated with each other, between the short wedges 3 and the massive iron core 5 and between the short wedges 3 and An eddy current that moves between the damper bar 4 and the damper bar 4 is generated. The moving eddy current tends to concentrate on the end of the short wedge 3 in the axial direction. Therefore, local heating occurs in this portion. If the heating is excessive, the rotor 2 may be damaged.

The present invention has been made in view of such a point, and reduces the concentration of the eddy current that moves between the damper bar and the massive iron core near the axial end of the short wedge of the rotor. It is an object of the present invention to provide a turbine generator capable of relaxing and preventing local heating due to eddy current concentration.

[0016]

According to the present invention, there is provided a turbine generator having a stator and a rotor, wherein the rotor comprises:
A massive iron core having a plurality of slots formed in a substantially cylindrical shape and extending in the axial direction on the side surface, a field winding wound in the plurality of slots of the massive iron core, and fixing the field winding A plurality of short wedges inserted in the axial direction on the opening side of each slot of the massive iron core, and a damper bar disposed below the plurality of short wedges in each slot of the massive iron core. And the plurality of short wedges, the massive iron core and the damper bar are electrically integrated with each other, and the short wedge has an electrical contact in the vicinity of an axial end thereof, and an electric contact in other portions. It is a turbine generator characterized by being weaker than a contact.

According to the present invention, the short wedge has weaker electrical contact in the vicinity of the axial end thereof than in the other portions. The concentration of the eddy current that moves between the damper bar and the massive iron core can be reduced.

In the present invention, since the short wedge has a shape in which the corner at the axial end is rounded, the electrical contact near the axial end of the short wedge is reduced at other portions. It can be weaker than the electrical contact.

In the present invention, by applying a paint for increasing the contact resistance near the axial end of the short wedge, the electrical contact near the axial end of the short wedge can be changed in other parts. It can be weaker than the electrical contact.

[0020]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are views showing an embodiment of a turbine generator according to the present invention. In addition,
In the embodiment of the present invention shown in FIGS.
The same components as those of the conventional example shown in FIGS. 5 to 5 are denoted by the same reference numerals, and will be described with reference to FIGS.

First, an embodiment of the present invention will be described with reference to FIG. 1 and FIGS. As shown in FIG. 3, the turbine generator of the present embodiment includes a rotor 2 rotatably supported in a casing 15 and a stator 1 provided around the rotor 2. . As shown in FIG. 3, the stator 1 of the turbine generator includes a field core 1.
0 and the field winding 12.

As shown in FIG. 4, the rotor 2 of the turbine generator has a massive iron core 5 having a substantially cylindrical shape. As shown in FIGS. 4 and 5, a plurality of slots 50 extending in the axial direction are formed on the side surface of the massive iron core 5. As shown in FIG. 5, a field winding 9 is wound in a slot 50 of the massive iron core 5, and the field winding 9 and the massive iron core 5 are insulated by a ground insulating layer 8. Have been.

As shown in FIGS. 4 and 5, a plurality of short wedges 3 for fixing the field winding 9 to the opening side of each slot 50 of the massive iron core 5 are sequentially inserted in the axial direction. ing. As shown in FIGS. 1 and 5, each short wedge 3 has a substantially rectangular parallelepiped main body 30 and a pair of left and right protruding portions 32 protruding outward from lower side surfaces of the main body 30.
Then, as shown in FIG.
A pair of left and right concave portions 52 corresponding to the both protruding portions 32 of the short wedge 3 are formed in 0.

The short wedge 3 is provided above the field winding 9.
A ground insulating member 6 for maintaining insulation between the side and the side is arranged.

Here, the thyristor starting method is adopted in the turbine generator of the present embodiment. In this starting method, a turbine generator is used as a variable-speed synchronous motor at the time of starting. That is, by using an inverter as a variable frequency power supply and gradually increasing the frequency of the AC power supply from 0, the rotation speed of the turbine generator (as an electric motor) is increased in synchronization with the power supply frequency.

At this time, the stator winding 12
The current supplied to (see FIG. 3) includes, in addition to the synchronous frequency component, a harmonic component that is not synchronized with the rotation speed. Then, an eddy current is induced in the rotor 2 by the harmonic components, which causes the structure of the rotor 2 to be heated. Therefore,
As shown in FIGS. 1 and 5, a conductive damper bar 4 is arranged below each of the plurality of short wedges 3 in each slot 50 of the massive iron core 5 in order to alleviate heating due to such eddy current. Have been.

Here, the thyristor-activated turbine generator has an operating state in a low rotation speed region unlike a normal generator. For this reason, even if the centrifugal force is small at such a low rotation, the short wedge 3 and the damper bar 4
Of the plurality of short wedges 3, the massive iron core 5, and the damper bar 4 must be kept in close contact with each other and fixed. Therefore, as shown in FIG. 5, the short wedge 3, the massive iron core 5 and the damper bar 4 are interposed between the damper bar 4 and the ground insulating member 6 on the field winding 9 by means of a leaf spring 7 or the like. 4 and 4 are brought into close contact with each other and fixed.

That is, irrespective of the operating state of the turbine generator, the plurality of short wedges 3, the massive iron core 5, and the damper bar 4 are closely adhered and fixed to each other so as to maintain an electrically integrated state. It has become. As shown in FIG. 5, a ground insulating layer 8 provided around the field winding 9 is provided.
Extends upward to the bottom of the short wedge 3 and
Also, insulation between the leaf spring 7 and the massive iron core 5 is maintained.

Next, in the present embodiment, as shown in FIG. 1, the short wedge 3 has a shape in which a corner 36 on the damper bar 4 side at an axial end 34 is rounded into a cylindrical shape. No. As a result, the short wedge 3 has weaker electrical contact in the vicinity of the end 34 than in other portions.

Next, the operation and effect of this embodiment having the above configuration will be described. According to the present embodiment, the short wedge 3 has weaker electrical contact in the vicinity of the axial end portion 34 thereof than in other portions. The concentration of the transfer current between the damper bar 4 and the massive iron core 5 can be reduced. For this reason, in the rotor 2, it is possible to prevent local heating due to eddy current concentration near the axial end 34 of the short wedge 3.

Next, another embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2, in the present embodiment, a corner 3 on the damper bar 4 side at an end 34 of each short wedge 3 is used.
5 is formed at a substantially right angle, and the surface around the corner 35 is coated with a paint 38 for increasing the contact resistance, unlike the above embodiment shown in FIG. 1 and the above embodiment shown in FIGS. 3 to 5.

Each short wedge 3 has an end portion 34 formed by applying a paint 38 for increasing contact resistance to a surface around a corner 35 on the damper bar 4 side at an end portion 34 in the axial direction. The electrical contact in the vicinity is weaker than the electrical contact in other parts. Therefore, according to this embodiment, the same operation and effect as those of the above embodiment can be obtained.

The range of application of the paint 38 in the present embodiment is not limited to the range shown in FIG. 2, but can be changed as needed. In addition, by combining this embodiment with the above-described embodiment, a paint 38 for increasing contact resistance is applied to the surface of the corner portion 36 of the short wedge 3 shown in FIG. You may.

[0034]

According to the present invention, the electrical contact near the axial end of the short wedge is weaker than the electrical contact at other portions, and therefore, the electrical contact near the axial end of the short wedge is reduced. In this case, the concentration of the eddy current moving between the damper bar and the massive iron core can be reduced. For this reason, in the rotor, local heating due to eddy current concentration near the axial end of the short wedge can be prevented.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a short wedge and a damper bar of a rotor in one embodiment of a turbine generator according to the present invention.

FIG. 2 is a partial perspective view showing a short wedge and a damper bar of a rotor in another embodiment of the turbine generator according to the present invention.

FIG. 3 is a view partially showing a conventional turbine generator, in which an upper half is shown in a longitudinal section and a lower half is shown in a side view.

FIG. 4 is a perspective view showing the rotor of the turbine generator shown in FIG. 3 in a partially broken manner.

FIG. 5 is a view showing a slot portion of the rotor shown in FIG. 4 in a cross section of the rotor.

FIG. 6 is a partial perspective view showing a short wedge and a damper bar in a conventional turbine generator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Short wedge 4 Damper bar 5 Lumped iron core 9 Rotor field winding 10 Stator field iron core 12 Stator winding 34 End of short wedge (axial direction) 35 End of short wedge A substantially right-angled corner on the lower side 36 A corner rounded into a cylindrical surface below the end of the short wedge 38 Paint for increasing contact resistance

Claims (3)

[Claims] 1. A turbine generator comprising a stator and a rotor, wherein the rotor has a substantially cylindrical shape and a plurality of slots formed in a side surface thereof and extending in the axial direction. Field windings wound in a plurality of slots, and a plurality of short wedges axially inserted into the opening side of each slot of the massive iron core to fix the field windings, In each slot of the massive core, a damper bar is provided below the plurality of short wedges, and the plurality of short wedges, the massive core and the damper bar are electrically integrated. The short wedge is characterized in that electrical contact near an axial end thereof is weaker than electrical contact in other portions. 2. The turbine generator according to claim 1, wherein the short wedge has a shape in which a corner at an axial end is rounded. 3. The short wedge is provided near its axial end.
The turbine generator according to claim 1, wherein a paint for increasing contact resistance is applied.