JPS62213558A - Rotor of superconducting rotary electric machine - Google Patents

Abstract

PURPOSE:To smoothly remove the heat of a superconducting field coil by forming an axial slot bottom groove communicating with a coil mounting shaft helium flowing hole in the bottom of the slot. CONSTITUTION:The rotor of a superconductive rotary electric machine is composed of a coil mounting shaft 2 having a helium flowing hole 23, a superconducting field coil 3, a helium outer cylinder 6, a wedge 19 and upper, lower filler 20, 21. In this case, an axial slot bottom groove 24 communicating with the hole 23 is formed in the bottom of a slot 17 formed in the shaft 2. Thus, the heat of the coil 3 is efficiently cooled by the helium flow rate increased by the slot bottom groove 24. Further, insulating creeping distance is increased in the difference between the width of the groove 24 and the diameter of the hole 23 to improve the dielectric strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the structure of a rotor of a superconducting rotating electric machine.

[Conventional technology]

Conventionally, as a rotor of this type, for example, Japanese Patent Application Laid-Open No. 57-2287
There is one disclosed in Publication No. 2, and its configuration is shown in FIG. In Figure 4, (1) is the torque tube, (2
) is the coil mounting shaft that forms the center of the torque tube (1), (3) is the superconducting field coil fixed to the coil mounting shaft (2), and (4) is the torque tube (1) and the coil mounting shaft. (2) is a room temperature damper that surrounds the coil mounting shaft (2), (5) is a low temperature damper that is disposed between this room temperature damper (4) and the coil mounting shaft (2), and (6) and (7) are the coil mounting shaft (2).
) is attached to the outer periphery and side surface of the helium outer cylinder-helium end plate, (8) and (9) are the drive side and non-drive side end shafts, respectively, Q (I is these end shafts (sl + (
9) is a slip ring for supplying field current, (6) is a heat exchanger formed or placed on the torque tube (1), and (2) is a side radiation shield.
α4 is a vacuum part.

In the rotor of the superconducting rotating machine having the above configuration, the superconducting field coil (
3) to an extremely low temperature, the electrical resistance becomes zero, and excitation loss is eliminated, thereby generating a strong magnetic field in this superconducting field coil (3), which is applied to the stator (not shown). Generates alternating current power. This superconducting field coil (
3) In order to cool and maintain the liquid helium at an extremely low temperature, liquid helium is passed from the center of the non-drive side end shaft (9) through an introduction pipe (not shown) to the helium outer cylinder (6) and the helium end plate (7). While supplying liquid helium to the liquid helium container formed by Use the torque tube (1) as a thin-walled cylinder 1
In addition, a heat exchanger (2) is provided, and the torque tube (1)
The most common structure is to reduce as much as possible the heat that penetrates into the cryogenic part through the heat sink.Furthermore, a side radiation shield is provided to reduce the heat that penetrates from the side by radiation.

On the other hand, the normal temperature damper (4) and the low temperature damper (5) shield the harmonic magnetic field from the stator, and the superconducting field coil (
3) and has the function of damping rotor vibrations caused by disturbances in the power system.
) generally functions as a vacuum outer cylinder, and the low-temperature damper also serves as a radiation shield for the helium container. In addition, in FIG. 4, the helium introduction inside the rotor, the piping constituting the exhaust system, and the helium introduction/discharge device connected to the rotor are omitted.

FIG. 5 is a cross-sectional view taken along line v-v in FIG.
) is the coil mounting shaft, (3) is the superconducting field coil, (6)
is the helium outer cylinder, (2) is the liquid helium reservoir, α
6 is a helium vapor space, αη is a slot that accommodates the superconducting field coil A/ (3) formed on the coil mounting shaft (2), and (G) is a side provided on both sides of the slot (B). (2) is a wedge that fixes the superconducting field coil (3); (Foundation) is the superconducting field coil (3)
The upper pawls and the lower pawls are in contact with the inner circumferential surface of
a).

(21a,). ) is the coil mounting shaft (2
) and the helium outer cylinder (6), and (b) is a coil mounting shaft helium flow hole provided in communication with the liquid reservoir (a) and the bottom of the slot (b). be.

Generally speaking, in superconducting rotating electric machines, there is an important technical problem in how to cool the superconducting field coil to a cryogenic temperature. In order to bring a superconducting field coil into a superconducting state, it is necessary to cool it below the superconducting transition temperature, and currently, helium is used as a cooling medium to maintain the absolute temperature at an absolute temperature of IK to 20K. On the other hand, in such extremely low temperature conditions, the specific heat of the superconducting field coil is extremely small, so the superconducting field coil may be damaged due to minute heat generation within one superconducting field coil or a small amount of heat entering the superconducting field coil. There is always a risk that the temperature will rise and exceed the superconducting transition temperature. Therefore, it is important in the design of superconducting rotating electric machines how to quickly remove the minute amount of heat generated within the superconducting field coil or the slight amount of heat entering the superconducting field coil to suppress the temperature rise of the superconducting field coil. Becomes a daint.

Next, the cooling operation will be explained based on FIG. Heat generated by slight heat generation within the superconducting field coil (3) or slight heat intrusion into the superconducting field coil (3) exists in a small gap around the superconducting field coil/L' (3). It is absorbed by helium. The helium, which expands due to heat absorption and becomes less dense, passes through the through hole (21a) of the lower parter (2) due to the natural convection of the centrifugal force field, passes through the helium flow hole (toward) of the coil mounting shaft (2), and becomes liquid. Reservoir (
appear in c). On the other hand, the helium shortage that occurs around superconducting field coil /1/ (3) is caused by the through hole (20
It is supplemented by helium flowing around the superconducting field coil (3) through a). The endothermically expanded helium is cooled by evaporating a portion of it in the liquid reservoir. The cooled helium enters around the superconducting field coil (3) from the helium flow hole (a) on another coil mounting shaft through the through hole (21a) of the lower pawl (2), and then flows into the upper pawl (housing). ) through hole (20a)
It passes through the gap between wedge 01 and exits to the helium flow path (a).

By performing the smooth natural circulation as described above, the superconducting field coil (3) is cooled, and the superconducting field coil # (3) is kept below the superconducting transition temperature.

[Problem that the invention seeks to solve]

In the rotor of a conventional superconducting rotating electrical machine, the helium inlet and outlet openings in the superconducting field coil lL/(3) are spaced widely, so as shown in Fig. Depending on the location, there is a large difference in the length of the helium flow path, and the cooling conditions also differ. Superconducting field coil/l/ (3)
If heat generation occurs at a location away from the inlet/outlet, it will be difficult for the helium that has absorbed the heat to quickly flow out through the coil mounting shaft helium flow hole (e) to the liquid reservoir (a), causing the superconducting field There was a high possibility that the temperature of the coil (3) would rise, exceeding the superconducting critical temperature and causing a normal conduction transition, causing the generator to stop functioning.Therefore, the spacing of the helium flow holes (to) on the coil mounting shaft was changed. Although it is conceivable to narrow it down, there is a problem that the manufacturing cost increases due to a decrease in the strength of the coil mounting shaft (2), an increase in cutting time, etc.

This invention was made to solve the above-mentioned problems, and aims to provide a rotor for a superconducting rotating electrical machine that smoothly removes heat from a superconducting field coil and does not cause normal conduction transition. .

[Means for solving problems]

The rotor of a superconducting rotating electric machine according to the present invention is provided with an axial slot bottom groove communicating with a coil mounting shaft helium flow hole at the bottom of the slot.

[Effect]

The rotor of the superconducting rotating electrical machine in this invention has a slot bottom groove that communicates with the coil mounting shaft helium flow hole provided at the bottom of the slot, which improves helium flow and facilitates heat removal from the superconducting field coil. This improves the performance of superconducting field coils.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In Figure 2, (21, +3), (6),
019 to @ have the same structure as the conventional rotor described above. (Incorporated) is an axial slot bottom groove that communicates with the coil mounting shaft helium flow hole (2) formed at the bottom of the slot α force.

The following operation will be explained. The heat generated by slight heat generation within the superconducting field coil (3) or by slight heat intrusion into the superconducting field coil (3) is transferred to the superconducting field coil/L'
It is absorbed by the helium that exists in the small gap around (3). The helium expands due to heat absorption and its density decreases, and the natural convection of the centrifugal force field causes the helium to expand into the lower part (2).
The liquid enters the through hole (21a), passes through the slot bottom groove (c) in the axial direction, passes through the coil mounting shaft helium flow hole (end), and exits to the liquid reservoir (end). On the other hand, the helium shortage that occurs around the superconducting field coil (3) is caused by the gap from the helium flow path (to the wedge) and the through hole (2) of the upper pawl (1).
0a) and is supplemented by helium flowing around the superconducting field coil /L/(3). The endothermically expanded helium is cooled by partially evaporating in the liquid reservoir (g). The cooled helium flows from the helium flow hole (to) on another coil mounting shaft to the slot bottom groove (c).
The through hole (21a) of the lower pawl (2) passes in the axial direction of the
), it enters around the superconducting field coil (3), and then exits to the helium channel (2) through the through hole (2Oa) of the upper pawl (e) and the gap between the wedge Q-hole. In this way, the superconducting field coil (3
) increases the flow rate of helium near the heat generating part of the superconducting field coil (3), and enables smooth natural circulation of helium, allowing efficient cooling of the superconducting field coil (3).
) is kept below the superconducting transition temperature. In other words, high-temperature helium that has absorbed heat from the superconducting field coil (3) does not accumulate around the superconducting field coil (3).
Normal conduction transitions do not occur and the generator does not stop functioning.

Further, as shown in Fig. 8, if the thickness of the lower pawl (C) is A, and the difference between the diameter of the through hole (21a) of the lower pawl (2) and the width of the slot bottom groove ■ is B, then , the insulation creepage distance is A+B. Therefore, the insulation creepage distance is increased by the difference between the width of the slot bottom groove (2) and the diameter of the helium flow hole (to) the coil mounting shaft, and the dielectric strength is improved.

〔Effect of the invention〕

As explained above, this invention has an axial slot bottom groove that communicates with the coil mounting shaft helium flow hole at the bottom of the slot, thereby improving helium flow and smoothing heat removal from the superconducting field coil. Therefore, the performance of the superconducting field coil can be improved, and a highly reliable rotor of a superconducting rotating electric machine can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a slot portion in a rotor of a superconducting rotating electric machine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the flow of helium according to the present invention, and FIG. 4 is a sectional view showing the overall concept of a rotor of a general superconducting rotating electrical machine; FIG. 5 is a sectional view taken along line v-v in FIG. 4; FIG. 6 is a cross-sectional view showing the flow of helium in the rotor of a conventional superconducting rotating electric machine. In the figure, (2) is the coil mounting shaft, (3) is the superconducting field coil, αη is the slot, and (F) is the slot bottom groove. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A superconducting field coil housed in a slot provided in a coil mounting shaft, and a coil mounting shaft provided with a helium flow hole extending radially from the slot to the center of the coil mounting shaft, wherein the slot A rotor for a superconducting rotating electric machine, comprising an axial slot bottom groove provided in a bottom portion thereof in communication with the coil mounting shaft helium flow hole.