JPH0817561B2 - Claw pole type synchronous generator - Google Patents

Description

The present invention relates to a generator in which a turbine and a compressor are mounted on both sides of a generator rotor, and in particular, an improved method of cooling an armature winding. The present invention relates to a claw pole type synchronous generator.

(Prior Art) FIG. 8 is a longitudinal sectional view of a conventional claw pole type synchronous generator, and FIG. 9 is a sectional view taken along the line IX-IX in FIG.
A non-magnetic material (1
Install the turbine (2) and compressor (3) on both sides of the generator rotor (1) with the interposition of 6). The generator rotor (1) is supported by bearings (4) and rotates at ultra-high speeds of tens of thousands of revolutions per minute. The stator of the generator is a stator core (5)
Is attached to a stator frame (6) through a non-magnetic core support cylinder (6a) and is wound around a slot (7) of the stator core, and an armature winding (8). Frame (6)
It consists of a field winding (9) mounted inside. Air gap (10) between generator rotor (1) and stator core (5)
Has a length g of about 1 to 2 mm.

(Problems to be solved by the invention) In the cooling of the conventional structure, the outer surface of the stator frame (6) is cooled, and the inner stator core (5), the armature winding (8),
The field winding (9) was cooled by heat conduction.

On the other hand, the heat generated inside the generator includes iron loss of the stator core (5), copper loss of the field winding (9) and armature winding (8), surface loss of the generator rotor (1) surface, and stirring. There is a loss. If this loss is cooled by the conventional cooling method, the armature winding (8) becomes hot.

Furthermore, the biggest factor that makes the armature winding (8) high temperature is
The heat from the turbine rotor (2) installed at the rotor end and the heat generated by the generator rotor causes the generator rotor (1) to reach a high temperature, and the heat on the generator rotor surface is stored in the air gap (10). The medium was transmitted to reach the armature winding (8), the winding temperature became extremely high, and in many cases the allowable temperature was exceeded.

The present invention has been made in view of the above problems of the conventional art, and an object thereof is to provide a claw pole type synchronous generator in which the temperature of an armature winding is lowered and the reliability of electrical insulation is improved. It is in.

[Structure of Invention]

(Means for Solving the Problem) In order to achieve the above-mentioned object, in the present invention, it is interposed in the air gap between the outer peripheral surface of a generator-driven rotor driven by a turbine and the inner peripheral surface of a stator core. A cylindrical can of ceramic material and a plurality of radial notches in the circumferential direction on the frusto-conical part for elastically fixing both ends of the can to the stator frame. A coolant is supplied from the outside of the stator frame to the inside of the stator frame, and a metal elastic body consisting of a retaining ring with the notch part slightly narrowed to the inner diameter side, or a corrugated plate wound in a cylindrical shape and corrugated in the circumferential direction. And a vent for venting the inner circumference of the iron core of the stator.

(Operation) By interposing a can in the air gap, the equivalent heat transfer rate from the generator rotor surface to the stator is reduced, and heat transfer is reduced.

In addition, the amount of heat generated by the armature winding is dissipated by causing the refrigerant to flow in the axial direction between the can and the stator core.

Since the can is fixed to the stator frame with a metal elastic body, it is possible to absorb a difference in thermal expansion and vibration and prevent damage to the can.

(Example) Example 1 Hereinafter, a first example of a claw pole type synchronous generator of the present invention will be described with reference to FIGS. 1 to 5.
In these figures, the same parts as those in the conventional structure shown in FIGS. 8 and 9 are designated by the same reference numerals and the description thereof will be omitted.

1 to 5, a cylindrical can (12) made of a ceramic material is inserted into the air gap (10) between the stator core (5) and the generator rotor (1), and the can (12) is inserted. Is fixed to the stator frame (6) with a loose fit by using a retaining ring (13) which is a metal elastic body. A ventilation port (14) is provided on the outer periphery of the stator frame (6), and the same gas as the working catalyst used in the turbine (2) and the compressor (3) is used, as indicated by the arrow in FIG. (6) Inject air, cool the inside and exhaust. At this time, the slot (7) around which the armature winding (8) is wound is made larger than in the conventional case, and the space inside the slot (7) is enlarged to form the ventilation path (15). The retaining ring (13) comprises a cylindrical portion (16) and a truncated cone portion (17), and the truncated cone (1
7) is provided with a plurality of radial notches (18) in the circumferential direction and is slightly squeezed to the inner diameter side to increase elasticity.

 Next, the operation of the first embodiment will be described.

Since the can (12) is part of the magnetic path (19),
A ceramic material is suitable because it is made non-conductive so that the magnetic path (19) is not disturbed and the temperature is high. Further, according to this structure, the temperature of the armature winding (8) exhibiting the conventional maximum temperature can be lowered by the following action.

First, the effect of the can (2) will be explained by the reduction of the heat transmission rate in which heat flows from the surface of the generator rotor (1) to the armature winding (8).

The equivalent heat transfer rate k for heat flowing from the generator rotor surface to the armature winding (8) is Where α = heat transfer coefficient between generator rotor and can λ ₁ = thermal conductivity of can made of ceramic material λ ₂ = thermal conductivity between can and armature winding t = cylindrical thickness of can (this In the embodiment, t = 1 mm) 1 = radial distance between the can and the inner peripheral surface of the stator core (1 = 0.5 mm in this embodiment).

Among them, α represents the heat transfer coefficient on the inner cylinder surface of the rotating double cylinder, and since the rotating Reynolds number becomes high, α also becomes large. λ ₁ / t is the heat transfer coefficient in the ceramic, which is much larger than α and λ ₂ / l. λ ₂ / l is much smaller than the other terms, and becomes the dominant factor of the heat transfer rate. On the other hand, in the conventional structure, heat is directly transferred from the surface of the generator rotor to the armature winding, and the heat transfer coefficient becomes high due to the high influence of the number of rotating Reynolds. Therefore, the heat transfer rate is also high.

According to the structure of the first embodiment, the equivalent heat transfer coefficient of the conventional structure is
About 1/10 is possible. The smaller the heat transfer rate, the smaller the heat transfer.

Next, the effect of flowing the refrigerant into the ventilation path (15) will be described. In the conventional structure, when the gap between the generator rotor (1) and the armature winding (8) is small and the number of rotating Reynolds is high, in order to flow the refrigerant in the axial direction, the ventilation resistance is large and the necessary refrigerant flow rate is required. Can't be washed away.

According to the first embodiment, since the generator rotor (1) is surrounded by the can (12), there is no circumferential flow between the can (12) and the armature winding (8), and there is no axial flow. Easy to flow. However, since the can (12) is inserted, the ventilation area is narrowed, and the ventilation passage (15) is provided in a part of the slot (7) to increase the ventilation area to reduce the ventilation resistance. In addition, the heat dissipation area in the slot (7) is widened to facilitate heat dissipation. Retaining ring (13) has several notches (18) around the circumference
Since it is slightly squeezed to the inner diameter side at the part, the can (12)
The can (12) is fixed so that there is no backlash, and the difference in thermal expansion between the stator frame (6) and the can (12) and the vibration of the can (12) are elastically absorbed.

Embodiment 2 FIGS. 6 and 7 show a second embodiment in which the fixing means of the can (12) is changed.

The can (12) is elastically coupled to the stator frame (6) via a corrugated plate (20) which is a metal elastic body made of a corrugated plate which is wound in a cylindrical shape and corrugated in the circumferential direction.

 The corrugated plate (20) uses a metallic material.

Also in this second embodiment, the difference in thermal expansion and vibration of the can (12) are absorbed by the same elastic action as in the first embodiment.

〔The invention's effect〕

As described above, according to the present invention, heat transfer from the generator rotor surface having a very high temperature condition to the stator side can be reduced by inserting a can, and further, in the stator frame, particularly in the slot. By passing the coolant, the temperature of the armature winding can be lowered.

Furthermore, by fixing the can made of a ceramic material to the stator frame with a snap ring or corrugated plate that is an elastic body, damage to the can can be prevented.

As a whole, it is possible to supply a claw pole type synchronous generator with improved reliability of the electrical insulation of the armature winding.

[Brief description of drawings]

1 is a longitudinal sectional view showing a first embodiment of a claw pole type synchronous generator of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 4 is an enlarged view of a main part of the figure, FIG. 4 is an elevation view showing the retaining ring of FIG. 3, FIG. 5 is a side view of FIG.
FIG. 6 is a longitudinal sectional view showing an essential part of the second embodiment, FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6, and FIG. 8 is a longitudinal sectional view showing a conventional example. 9 is a sectional view taken along the line IX-IX in FIG. 1 ... Generator rotor, 2 ... Turbine, 5 ... Stator core, 6 ... Stator frame, 7 ... Slot, 8 ... Armature winding, 10 ... Air gap, 12 ... Can, 13 ... Retaining ring that is an elastic body, 15 ... Ventilation path, 20 ... Corrugated plate that is an elastic body.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunzo Watanabe 2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toshiba Keihin Office (56) Reference JP 1-268446 (JP, A) Sho 59-86875 (JP, U)

Claims (1)

[Claims] 1. A cylindrical can of ceramic material interposed in an air gap between an outer peripheral surface of a generator-driven rotor driven by a turbine and an inner peripheral surface of a stator core, and both ends of the can are fixed to a stator frame. A retaining ring with a plurality of radial notches provided in the circumferential direction for the purpose of elastically fixing to the cylindrical part and a truncated cone part, with the notch part slightly narrowed to the inner diameter side,
Or, a metal elastic body made of a corrugated plate corrugated in a cylindrical shape and corrugated in the circumferential direction, and a ventilation path for supplying / discharging a refrigerant from the outside of the stator frame to the inside of the stator core and ventilating the inside of the stator core. A claw pole type synchronous generator characterized by being equipped.