JPH06178480A - Rotary electric machine - Google Patents

Abstract

PURPOSE:To enhance the reliability of the electric machine in its abnormality by restraining that a magnetic-pole-part damping winding is overheated by a rotor surface current. CONSTITUTION:The thickness of a magnetic-pole-part wedge 11 on the surface of a magnetic-pole part in made thinner than the thickness of a coil-part wedge in a field coil part on a cylindrical rotor, a magnetic-pole-part clamping winding 10 which restrains a rotor surface current is made thicker toward the surface direction of the magnetic-pole part, and a cooling duct 12 which is passed to the shaft direction of the cylindrical rotor is formed at the inside of the magnetic-pole-part damping winding 10. Then, a plurality of discharge holes 13 which are passed to the side of an opening part in a slot from the cooling duct 12 are formed, a plurality of communication holes 14 are formed in the magnetic-pole-part wedge 11 in such a way that the individual discharge holes 13 communicate with the opening part in the slot, a plurality of intake ducts 16 which make central parts on both ends of the rotor communicate individually with both ends of the cooling duct 12 for the magnetic-pole-part damping winding 10 are installed, and the inside of the magnetic-pole-part clamping winding 10 is cooled by rotating the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine provided with a cylindrical rotor having magnetic poles such as a turbine generator, and more particularly to a rotary electric machine which suppresses overheating of a braking winding of the magnetic poles. .

[0002]

2. Description of the Related Art In recent years, in rotary electric machines such as turbine generators, the capacity of a single machine has remarkably increased. As a cause of this, the miniaturization of the rotary electric machines and the progress of the field coil cooling system have been advanced. There is. Here, the progress of the cooling system is particularly remarkable, and by cooling the field coil with a cooling gas, heat generation of the field coil in a steady equilibrium state is suppressed and safety is improved.

By the way, in this type of rotating electric machine, an abnormal current may flow through the rotor body when a failure or a system accident occurs. The abnormal current at this time locally causes an extreme temperature rise in the rotating electric machine, so even with a cooling method that is sufficiently satisfactory in the steady equilibrium state, an extreme temperature rise at the time of an accident is
Sometimes it isn't enough, and it can cause the worst.

For example, when a line short-circuit / ground short-circuit occurs at a terminal or system of a rotating electric machine, an unbalanced load is present, or there is a load containing harmonics, the rotor of the rotating electric machine is Non-synchronized reverse phase current / harmonic current flows. The magnetic flux generated by the anti-phase current / harmonic current induces a large current circulating on the surface of the rotor. Therefore, the induced rotor surface current causes the rotor surface to overheat, and the rotating electric machine is put into a dangerous state.

On the other hand, various braking windings are used as means for suppressing such rotor surface current. As the most advanced braking winding, a method is used in which the braking winding is inserted not only between the field coil and the wedge but also in the magnetic pole portion.

[0006]

However, in the rotary electric machine in which the braking winding is inserted by the above method,
Since there is no passage of cooling gas in the magnetic pole portion like the field coil portion, there is a problem that the braking winding itself is overheated due to the rotor surface current induced during an abnormality. Such overheating of the braking winding causes the rotary electric machine to be in a dangerous state, which is a major limitation in reducing the size of the rotary electric machine and increasing the capacity of a single machine.

The present invention has been made in consideration of the above circumstances, and provides a rotating electric machine capable of improving reliability in an abnormal state by suppressing overheating of a magnetic pole braking winding due to a rotor surface current. The purpose is to

[0008]

The invention according to claim 1 is characterized in that a field coil portion is formed by inserting a field coil into a plurality of slots formed along an axial direction and fixing the field coil portion with a wedge.
Damping windings for suppressing the rotor surface current are inserted in a plurality of slots formed along the axial direction between the field coil portions and having the same wedge shape as the wedge shape of the field coil portions. In a rotating electric machine provided with a cylindrical rotor having a magnetic pole portion fixed by a wedge, the thickness of the wedge of the magnetic pole portion is made thinner than the thickness of the wedge of the field coil portion,
The rotary electric machine has a thickness of the braking winding increased by an amount corresponding to a reduction in thickness of the wedge of the magnetic pole portion.

According to a second aspect of the present invention, in the rotary electric machine according to the first aspect, a cooling duct is formed inside the braking winding for passing cooling gas in the axial direction of the cylindrical rotor. A plurality of discharge holes are formed through the cooling duct to the opening side of the slot, and a plurality of communication holes are formed in the wedge of the magnetic pole so that the discharge holes and the opening are in communication with each other. Also, a plurality of intake ducts that individually communicate the central portions of both ends of the rotor with both ends of the cooling duct of the braking winding are provided, and the rotation of the rotor allows the cooling gas to pass through the inside of the braking winding. Is a rotating electric machine that cools the braking winding.

[0010]

Therefore, in the invention corresponding to claim 1, since the braking winding has a large cross-sectional area and is brought close to the rotor surface by taking the above means, the inflow amount of the rotor surface current is increased. It is possible to suppress overheating by increasing the current density and decreasing the current density.

Further, according to the invention corresponding to claim 2, the rotation of the rotor causes the cooling gas to pass from the intake duct through the cooling duct formed in the braking winding, through the exhaust hole and the ventilation hole, and the rotor. Since it flows to the outside, the braking winding can be directly cooled to prevent the magnetic pole portion from overheating, and the reliability of the rotor can be improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a cylindrical rotor used in the rotating electric machine according to the present invention.

This cylindrical rotor 1 is provided in a cooling gas atmosphere and has a plurality of field coil portions 2 on its outer peripheral portion.
And the magnetic pole portion 3 are respectively provided, and both ends of the field coil portion 2 and the magnetic pole portion 3 are fixed by holding rings 4.

As shown in FIG. 2, the field coil section 2 has a rotor 1
A plurality of coil section slots 5 are formed on the outer circumference of each of them in the axial direction. Each of these coil portion slots 5 comprises a coil insertion slot portion 5a and a wedge insertion slot portion 5b wider than the coil insertion slot portion 5a on the opening side thereof,
A field coil 6 is wound around the coil insertion slot portion 5a, and a coil braking winding 8 is inserted on the outside thereof to insert a coil wedge 7 into the wedge insertion slot portion 5b so that the field coil 6 is subjected to centrifugal force. It is fixed in contrast.

On the other hand, the magnetic pole portion 3 has a rotor 1 as shown in FIG.
A plurality of magnetic pole portion slots 9 shallower than the coil portion slots 5 are formed in the axial direction between the field coil portions 2 on the outer circumference. Each of the magnetic pole portion slots 9 is composed of a braking winding insertion slot portion 9a and a wide wedge insertion slot portion 9b on the opening side thereof, and the braking winding insertion slot portion 9a has a magnetic pole portion thicker than the coil portion braking winding 8. The braking winding 10 is inserted, and the magnetic pole wedge 11 thinner than the coil wedge 7 is inserted into the wedge insertion slot 9b to fix the magnetic pole braking winding 10 against centrifugal force.

Here, the magnetic pole part braking winding 10 is composed of two conductors having grooves in the axial direction, and the cooling duct 12 that comes out in the axial direction is formed by stacking these two conductors so that the grooves face each other. A plurality of discharge holes 13 as shown in FIG. 4 which are formed in the outer conductor and pass through to the slot opening side are provided in communication with the cooling duct 12. In addition, the magnetic pole wedge 11 has discharge holes 1 of the magnetic pole braking winding 10.
3 and a plurality of communication holes 14 so that the rotor 3 and the outside of the rotor communicate with each other.
Are provided respectively.

On the other hand, as shown in FIG. 4, an insulator 15 is provided in the inner diameter portion of the retaining ring 4, and the insulator 15 cools the magnetic pole braking winding 10 from the center of both ends of the cylindrical rotor 1. Intake ducts 16 that individually communicate with both ends of the duct 12 are formed.

Next, the operation of the rotating electric machine provided with the cylindrical rotor thus constructed will be described. First, when the cylindrical rotor 1 rotates in the cooling gas atmosphere, the cooling gas is discharged from the cooling duct 12 of the magnetic pole braking winding 10 through the discharge hole 13 and the communication hole 14 by the centrifugal force.

In this case, the cooling duct 12 has a reduced gas pressure due to the discharge of the cooling gas, so that the cooling gas flows in from the intake duct 16 and the cooling gas flows from the magnetic pole braking winding 10 and the magnetic pole wedge 11 around it. While removing heat, the rotor 1 is similarly discharged to the outside of the rotor through the discharge hole 13 and the communication hole 14 by the centrifugal force of the rotor 1. Therefore, the cylindrical rotor 1
Due to the rotation, the cooling gas is circulated to directly cool the magnetic pole braking wire 10 and the magnetic pole wedge 11.

On the other hand, in the field coil unit 2, the field coil 6 is directly cooled by the cooling gas, and the cooling gas passes through the slots to release the heat of the coil braking winding 8 and the coil wedge 7. It is cooled by being continuously deprived and discharged.

In this state, when a reverse phase load is applied or an accident occurs, a rotor surface current is induced on the rotor surface. Since this rotor surface current is made to flow in the axial direction mainly by the braking windings 8 and 10 and the wedges 7 and 11 arranged in the axial direction, the circulating current flowing on the rotor surface is reduced.

In this case, since the magnetic pole braking winding 10 has two conductors stacked to have a thickness as compared with the coil braking winding 8, a larger amount of rotor surface current flowing on the surface is taken in. , The current density is reduced and overheating is suppressed. In addition, the magnetic pole braking winding 10 is provided in the cooling duct 1.
Since the cooling gas is supplied to the rotor 2 from the intake ducts 16 at both ends of the rotor, the cooling effect is enhanced.

As described above, the magnetic pole wedge 1 is used in this embodiment.
By making 1 thin and making the magnetic pole braking winding 10 thick, the magnetic pole braking winding 10 is brought close to the rotor surface,
Since a large amount of the rotor surface current is taken in and the current density of the rotor surface current flowing in the magnetic pole part braking winding 10 is reduced, the rotor surface current is further suppressed and the magnetic pole part braking winding 10 is reduced. The overheating of can be suppressed.

A cooling duct 12 is provided in the thickened magnetic pole braking winding 10 so that the cooling gas passes through the cooling duct 12 to remove heat from the surrounding magnetic pole braking winding 10 and magnetic pole wedge 11. Since it is made to flow to the outside of the rotor, it is possible to prevent the magnetic pole portion 3 from overheating due to the rotor surface current. Further, in the present embodiment, since the magnetic pole portion 3 can be prevented from being overheated, it is possible to improve the resistance to an unbalanced load and the resistance to an accident.

Further, even if the magnetic pole braking winding 10 is fixed by the thinned magnetic pole wedge 11, the magnetic pole portion 3 has a field winding closer to the inner diameter side of the rotor 1 than the magnetic pole braking winding 10. Since the magnetic pole wedge 11 can have a sufficient strength against the centrifugal force of the magnetic pole braking winding 10, the reliability during operation can be maintained. Further, since this embodiment can be realized without changing the dimensions of the slot portion of the rotor 1, it can be carried out relatively easily without replacing the rotor body. The present invention can be variously modified and implemented without departing from the scope of the invention.

[0026]

As described above, according to the present invention, the braking winding is provided so as to have a large cross-sectional area so as to be close to the rotor surface. The current density of the rotor is reduced, and the cooling gas taken in from the intake duct through the cooling duct formed in the braking winding is passed through while removing the heat of the surroundings and flowed to the outside of the rotor. It is possible to provide a rotating electric machine that can suppress overheating of the magnetic pole braking winding due to the surface current and can improve reliability in the event of an abnormality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cylindrical rotor used in a rotary electric machine according to an embodiment of the present invention.

FIG. 2 is a view showing a coil section slot in the embodiment.

FIG. 3 is a view showing a magnetic pole slot according to the embodiment.

FIG. 4 is a view showing a passage of cooling gas in the embodiment.

[Explanation of symbols]

1 ... Cylindrical rotor, 2 ... Field coil part, 3 ... Magnetic pole part, 7
... coil wedge, 10 ... magnetic pole braking winding, 11 ... magnetic pole wedge, 12 ... cooling duct, 13 ... discharge hole, 14 ... communication hole,
15 ... Insulator, 16 ... Intake duct.

Claims (2)

[Claims] 1. A field coil portion formed by inserting a field coil into a plurality of slots formed along the axial direction and fixing the field coil with a wedge, and formed between the field coil portions along the axial direction. A cylinder having a magnetic pole part formed by inserting a braking winding for suppressing a rotor surface current into a plurality of slots having the same wedge shape as the wedge shape of the field coil portion and fixing them by the wedges In a rotary electric machine including a shaped rotor, the thickness of the wedge of the magnetic pole portion is made thinner than that of the wedge of the field coil portion, and the thickness dimension of the braking winding is reduced by the thickness of the wedge of the magnetic pole portion. A rotating electrical machine characterized by a large size. 2. The rotating electric machine according to claim 1, wherein a cooling duct that allows cooling gas to pass in the axial direction of the cylindrical rotor is formed inside the braking winding, and the cooling duct is connected to the cooling duct. A plurality of discharge holes are formed on the side of the opening, and a plurality of communication holes are formed in the wedge of the magnetic pole so that the discharge holes and the opening communicate with each other. A plurality of intake ducts that individually communicate the parts to both ends of the cooling duct of the braking winding,
A rotating electric machine, wherein a cooling gas is passed through the inside of the braking winding by the rotation of the rotor to cool the braking winding.