Fluid state detection device, evaporative cooling system and motor

Abstract

The invention relates to the technical field of fluid detection, particularly provides a fluid state detection device, an evaporative cooling system and a motor, and aims to solve the problem of how to realize online detection of a fluid state in the evaporative cooling system. In order to achieve the purpose, the fluid state detection device provided by the invention is used for being arranged in an evaporative cooling system in a communicating manner, and the detection device comprises a main body part which is internally provided with a cavity for fluid to pass through; the perforated plate structure is connected with the main body part, and the perforated plate structure is located in the cavity so that the fluid can pass through the perforated plate structure; the pressure detection element is used for detecting fluid pressure on the two sides of the perforated plate structure; and the data processing module is in communication connection with the pressure detection element, and the data processing module determines the fluid flow according to a detection value of the pressure detection element. On-line detection of the working medium flow can be achieved in the operation process of the evaporative cooling system, and the method has great significance in guaranteeing safe and stable operation of the system.

Description

Technical Field

[0001] This application relates to the technical field of fluid detection, and specifically provides a fluid state detection device, an evaporation cooling system, and an electric machine. Background Art

[0002] Currently, evaporation cooling technology is widely used in the cooling of power equipment such as large synchronous motors or hydro-generators due to its strong cooling effect, good insulating properties of the phase change working medium, non-toxic and non-corrosive properties, etc. Moreover, the evaporation cooling system relies on the pressure difference generated during the vaporization process of the phase change working medium to achieve self-circulation, overcoming problems such as high operating pressure in traditional water-cooling systems and short circuits of electrical components easily caused by leakage.

[0003] For the evaporation cooling system, detecting parameters such as the working medium flow rate, moisture content, and working medium flow state during its operation is of great significance for ensuring the safe and stable operation of the system. In practical applications, considering the influence of factors such as the self-circulation head of the evaporation cooling system, in related technologies, some parameters of the working medium are usually measured offline during shutdown. However, this method is difficult to ensure the safety and stability of the system because it cannot perform online detection of the fluid state during the operation of the evaporation cooling system.

[0004] Correspondingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] This application aims to solve the above technical problems, that is, to solve the problem of how to achieve online detection of the fluid state in the evaporation cooling system.

[0006] In a first aspect, this application provides a fluid state detection device, which is used to be connected in the evaporation cooling system. The detection device includes:

[0007] A main body part, which has a chamber inside for fluid to pass through;

[0008] A porous plate structure, which is connected to the main body part and is located inside the chamber, so that the fluid can pass through the porous plate structure;

[0009] A pressure detection element, which is used to detect the fluid pressure on both sides of the porous plate structure;

[0010] A data processing module, which is communicatively connected to the pressure detection element, and the data processing module determines the fluid flow rate according to the detection value of the pressure detection element.

[0011] In a technical solution of the above fluid state detection device, the detection device further includes:

[0012] A conductivity detection element, whose detection end extends into the chamber and is used to detect the conductivity of the fluid.

[0013] In one technical solution of the above fluid state detection device, the conductivity detection element is embedded in the porous plate structure, and the detection end of the conductivity measurement element extends into the pores of the porous plate structure.

[0014] In one technical solution of the above fluid state detection device, a ring plate is extended and provided around the porous plate structure. The ring plate extends out of the outer side of the main body part and is hermetically connected to the main body part, and the data processing module is arranged on the ring plate.

[0015] In one technical solution of the above fluid state detection device, a vibration sensor is embedded in the ring plate. The vibration sensor is used to detect the vibration amount of the porous plate structure;

[0016] The data processing module is also communicatively connected to the vibration sensor. The data processing module determines the flow state of the fluid according to the detection value of the vibration sensor.

[0017] In one technical solution of the above fluid state detection device, a plurality of vibration sensors are evenly distributed along the circumferential direction of the ring plate.

[0018] In a second aspect, the present application provides an evaporative cooling system, which includes:

[0019] A condenser, and a gas collecting pipe and a liquid return pipe respectively connected to both ends of the condenser. The gas collecting pipe and the liquid return pipe are both connected to the cooling pipeline configured by the heat source to form a circulation loop;

[0020] The detection device according to any one of the first aspects, which is communicatively arranged in the liquid return pipe.

[0021] In one technical solution of the above evaporative cooling system, both ends of the main body part and the liquid return pipe are connected by a flange.

[0022] In a third aspect, the present application provides an electric motor, which includes:

[0023] A rotor, which includes an excitation winding, and a hollow wire is arranged in the excitation winding;

[0024] The evaporative cooling system according to any one of the second aspects, which is arranged on the rotor to cool the excitation winding. The gas collecting pipe and the liquid return pipe are both connected to the hollow wire to form the circulation loop.

[0025] In one technical solution of the above electric motor, the liquid return pipe includes an axial liquid return section extending along the axial direction of the rotor and a radial liquid return section extending along the radial direction of the rotor. The detection device is communicatively arranged in the radial liquid return section.

[0026] As described above, in the case of adopting the above technical solution, the present application disposes the fluid state detection device in the radial liquid return section of the liquid return pipe. In this way, not only the measurement of the fluid flow rate in the loop is realized by combining the porous plate structure and the pressure detection element, but also a certain flow resistance is introduced at the position of the liquid return pipe close to the hollow wire of the exciting winding through the porous plate structure, reducing the pressure at the inlet of the hollow wire of the exciting winding, which is beneficial to improving the cooling efficiency of the evaporation cooling system.

[0027] Furthermore, the present application integrates the conductivity detection element and the vibration sensor into the porous plate structure, realizing the synchronous detection of fluid flow rate, moisture content, and fluid flow state on the same detection device, improving the integration degree of the detection device. Description of the Drawings

[0028] The preferred embodiments of the present application will be described below with reference to the drawings. In the drawings:

[0029] Figure 1 is a schematic diagram of an evaporation cooling system according to an embodiment of the present application and its installation on a motor rotor

[0030] Figure 2 is a cross-sectional view of a fluid state detection device according to an embodiment of the present application;

[0031] Figure 3 is Figure 2 a plan view of the fluid state detection device in

[0032] In the figure, the reference numerals refer to the following:

[0033] 1, condenser; 2, gas collecting pipe; 3, liquid return pipe; 4, fluid state detection device; 41, main body part; 42, porous plate structure; 421, ring plate; 43, pressure detection element; 44, data processing module; 45, conductivity detection element; 46, vibration sensor; 5, flange;

[0034] 100, exciting winding; 200, chamber. Detailed Embodiments

[0035] The preferred embodiments of the present application will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present application and are not used to limit the protection scope of the present application. Those skilled in the art can adjust them as needed to adapt to specific application scenarios.

[0036] It should be noted that in the description of this application, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the relevant devices or components must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to this application. In addition, ordinal numbers such as "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0037] In addition, it should also be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] For the evaporation cooling system of an electric motor, parameters such as the pressure, flow rate, moisture content, and flow state of the internal fluid during its operation are all of reference significance for the operation of the system. For example, the flow rate of the liquid working medium in the evaporation cooling system directly affects the heat transfer efficiency of evaporation cooling. Insufficient flow rate will lead to insufficient evaporation, reducing the cooling efficiency. At the same time, considering the safety and stability of the system, abnormal flow rate (such as too low) may also cause local dry burning of the evaporator and even damage the equipment. Therefore, online detection of the flow rate of the liquid working medium in the evaporation cooling system is related to aspects such as the cooling performance, safety, and equipment life of the system, and is of great significance for maintaining the safe and stable operation of the system. However, for the evaporation cooling system, due to its limited self-circulation head, when a flow detection device is connected in series in the system, system resistance will be introduced, which will have an adverse impact on the circulation of the working medium. Therefore, there is currently no technology in the industry for online flow monitoring of evaporation cooling systems.

[0039] In addition, during the long-term operation of the evaporation cooling system, affected by various factors such as condenser condensation, introduction of external air during condenser exhaust maintenance, and leakage of secondary cooling water, there is a risk of change in the moisture content of the cooling working medium. An increase in the moisture content in the system not only affects the cooling efficiency, but also causes a change in the insulation performance of the working medium, thereby affecting the safe operation of the electric motor. Therefore, detecting the moisture content of the working medium is also of great significance for the cooling efficiency and operation safety of the system. However, currently, the operating generator sets usually perform offline detection of the moisture content of the working medium in the system during motor shutdown maintenance. But offline detection is difficult to further ensure the safety and stability of the system in real time because it cannot obtain the moisture content of the working medium during the operation of the system.

[0040] Finally, the flow state of the working fluid during the operation of the evaporative cooling system is also of great reference significance. For example, whether the liquid working fluid is in laminar flow or turbulent flow during the circulation process, and the degree of turbulence can reflect whether there are phenomena such as blockage or liquid shortage in the fluid in the system. Currently, the industry does not involve technologies for online detection of the fluid state.

[0041] Currently, for the online detection of the working fluid in the evaporative cooling system, it generally only involves parameters such as pressure and temperature. It is difficult to make a more comprehensive analysis of the fluid state based on these parameters alone. Based on this, the present application aims to solve the problem of how to online measure parameters such as the flow rate, moisture content, and flow state during the operation of the evaporative cooling system to improve the safety and stability of the system operation.

[0042] Refer to Figure 1 and Figure 2 , Figure 1 FIG. is a schematic diagram of an evaporative cooling system according to an embodiment of the present application and its installation on a motor rotor. Figure 2 FIG. is a cross-sectional view of a fluid state detection device according to an embodiment of the present application.

[0043] The evaporative cooling system includes a condenser 1, a gas collecting pipe 2, a liquid return pipe 3, and a fluid state detection device 4. In the present application, taking the application of the evaporative cooling system in the cooling of the motor rotor as an example for exemplary illustration ( Figure 1 the vertical line on the right side of the evaporative cooling system in FIG. is the axis of the motor shaft), the rotor of the motor includes an exciting winding 100. The exciting winding 100 has a hollow wire inside, and the cooling working fluid in the evaporative cooling system can flow through the hollow wire to cool the exciting winding 100.

[0044] Specifically, the condenser 1 is located at the top of the rotor and on the side close to the motor shaft. The gas collecting pipe 2 is connected to the upper end of the condenser 1, the liquid return pipe 3 is connected to the lower end of the condenser 1, the fluid state detection device 4 is connected and arranged in the liquid return pipe 3, and both the gas collecting pipe 2 and the liquid return pipe 3 are connected to the hollow wire in the exciting winding 100 to form a closed circulation loop. It should be noted that the "connection" between the pipelines described in the present application includes mechanical connection and the connection between the pipelines.

[0045] Refer to Figure 2 and Figure 3 , the fluid state detection device 4 includes a main body part 41, a perforated plate structure 42, a pressure detection element 43, and a data processing module 44.

[0046] The main body part 41 can be selected as a tubular component, and both ends thereof have openings, and there is a chamber 200 inside for the fluid (in the present application, the cooling working fluid is used as the fluid for illustration) to pass through.

[0047] The porous plate structure 42 is connected to the main body 41. The porous plate structure 42 is located within the chamber 200, enabling fluid to pass through the porous plate structure 42. In one embodiment of the present application, a ring plate 421 is provided extending along the four peripheral edges of the porous plate structure 42. The ring plate 421 can be a solid plate body, and the ring plate 421 is fixedly connected to the main body 41. A sealed state exists between the ring plate 421 and the main body 41, thereby ensuring the tightness of the chamber 200, and the ring plate 421 extends outside the main body 41. Thus, the porous plate structure 42 is fixed to the main body 41 through the ring plate 421. Optionally, the cross-section of the porous plate structure 42 is parallel to the cross-section of the main body 41, enabling fluid to vertically pass through the porous plate structure 42.

[0048] It should be noted that the porous plate structure 42 is a commonly used component in the field of evaporative cooling. According to requirements, its specific form can be a single-layer porous plate, a multi-layer composite porous plate, or even a 3D porous structure (such as a sintered porous plate, a foam metal, etc.) according to the structural hierarchy classification. According to the pore type classification, it can be a round hole, a square hole, or a special-shaped hole, etc. The arrangement of the holes can be a uniform array arrangement, a gradually changing density arrangement, or even a random arrangement, etc. As described above, in the embodiment of the present application, the porous plate structure 42 is taken as a composite layer structure and is arranged in a circular hole array form for exemplary illustration, but the present application does not limit the specific structural form of the porous plate structure 42, and those skilled in the art can make corresponding adjustments according to actual requirements.

[0049] The pressure detection element 43 is installed on the main body 41, and its detection end extends into the chamber 200. The pressure detection element 43 has two detection ends, which are respectively connected to different sides of the porous plate structure 42 for detecting the fluid pressures on both sides of the porous plate structure 42.

[0050] The data processing module 44 is located outside the main body 41. The data processing module 44 can be installed on the ring plate 421. The data processing module 44 is communicatively connected to the pressure detection element 43 and can obtain the detection value of the pressure detection element 43, thereby being able to determine the fluid flow rate in the circulation loop according to the detection value of the pressure detection element. Specifically, the pressure detection element 43 in the present application can be a differential pressure sensor. As a throttling element, when the fluid flows through the porous plate structure 42, a pressure difference will be generated on both sides of it. According to Bernoulli's equation and the principle of orifice flowmeter, the flow rate is proportional to the square root of the pressure difference. Thus, the fluid flow rate value in the circulation loop can be calculated according to the above relationship.

[0051] Refer to Figure 1When the evaporative cooling system is applied to cooling the motor rotor, the condenser 1 is located on the side close to the motor shaft, the gas collecting pipe 2 has an axial gas collecting section and a radial gas collecting section, and similarly, the liquid return pipe 3 has an axial liquid return section and a radial liquid return section. During the operation of the motor, the liquid working medium absorbs the heat generated by the excitation winding 100, and the temperature continues to rise until a phase change occurs, which is called a gas-liquid two-phase state. Due to the density difference between the gas-liquid two-phase working medium, under the action of the centrifugal force generated by the rotation of the rotor, the gaseous working medium moves along the radial gas collecting section of the gas collecting pipe 2 toward the side close to the shaft, enters the condenser 1 for heat exchange, and becomes a liquid working medium again in the condenser 1. After it is converted into a liquid working medium again, it flows downward along the liquid return pipe 3 due to gravity, and is accelerated to flow back to the hollow conductor of the excitation winding 100 in the radial liquid return section of the liquid return pipe 3 by the centrifugal force, and so on. The circulation pressure head generated by the density difference between the gas-liquid two-phases under the high centrifugal field is used to form a self-circulation.

[0052] In the above process, as for the flow state of the fluid (liquid medium) in the liquid return pipe 3, under the action of centrifugal force, the fluid flow rate of the radial liquid return section of the liquid return pipe 3 begins to accelerate, especially before the fluid enters the hollow wire of the excitation winding 100 (that is, the end of the radial liquid return section of the liquid return pipe 3), the fluid flow rate reaches the highest, and accordingly, the fluid pressure also reaches the highest. The phase change point temperature of the medium is closely related to the pressure, and the phase change point temperature increases with the pressure increase. In this way, when the fluid pressure entering the hollow wire of the excitation winding 100 is too high, it will cause the starting point of the phase change of the liquid medium to be delayed under the same heat load, which is not good for the cooling effect of the entire evaporative cooling system, and will cause the temperature level along the process of the phase change of the medium to increase, reducing the cooling efficiency. Based on this, the present application sets the fluid state detection device 4 in the radial return liquid section of the return liquid pipe 3. In this way, not only the measurement of the fluid flow in the circuit is realized by combining the porous plate structure 42 and the pressure detection element 43, but also a certain flow resistance is introduced through the porous plate structure 42 at the position of the return liquid pipe 3 close to the hollow conductor of the excitation winding 100, so that the pressure at the entrance of the hollow conductor of the excitation winding 100 is reduced, which is beneficial to improve the cooling efficiency of the evaporative cooling system.

[0053] Reference Figure 2 and Figure 3 In one embodiment of the present application, a conductivity detection element 45 is also embedded in the porous plate structure 42. The conductivity detection element 45 can be a structure such as a conductivity probe, which is used to measure the conductivity of the fluid, thereby obtaining the water content of the fluid, reflecting the insulation performance of the fluid.

[0054] The detection end of the conductivity detection element 45 extends into the pores of the porous plate structure 42, so that the detection end of the conductivity detection element 45 can be in direct contact with the fluid to measure the conductivity of the fluid. The end of the conductivity detection element 45 far from its detection end extends along the annular plate 421 to the outside of the main body 41. According to actual needs, multiple conductivity detection elements 45 can be arranged on the porous plate structure 42 and distributed in the pores at different positions of the porous plate structure 42 to improve the detection accuracy by means of multi-point measurement.

[0055] In this way, by integrating the conductivity detection element 45 into the porous plate structure 42, the moisture content of the fluid can be measured without affecting the working fluid circulation, which is of great significance for the safe and stable operation of the evaporative cooling system.

[0056] Referring to Figure 2 and Figure 3 , in an embodiment of the present application, a vibration sensor 46 is embedded in the annular plate 421 (for example, in one way, a groove can be opened on one surface of the annular plate 421, and the vibration sensor 46 is embedded in the groove). The vibration sensor 46 is used to detect the vibration amount of the porous plate structure 42, and the data processing module 44 is also communicatively connected to the vibration sensor 46. After receiving the vibration signal of the vibration sensor 46, the data processing module 44 can determine the flow state of the fluid according to the vibration signal.

[0057] Specifically, during the process of the fluid passing through the porous plate structure 42, the porous plate structure 42 will generate vibrations, and these vibrations will be transmitted along the porous plate structure 42 to the annular plate 421. At this time, the vibration sensor 46 obtains the vibration signal of the annular plate 421, thereby indirectly reflecting the flow state of the fluid. For example, when the amplitude of the vibration signal is low and the frequency band is narrow, it indicates that the fluid may be in a laminar flow state, and at this time, the flow state of the liquid working fluid in the loop is relatively stable. When the amplitude of the vibration signal is high, the vibration energy is dispersed and the high-frequency components are rich, it indicates that the fluid may be in a turbulent flow state, and at this time, the stability of the flow state of the liquid working fluid in the loop is relatively poor, and the evaporative cooling system may be abnormal.

[0058] Referring to Figure 3 , in one implementation, a plurality of vibration sensors 46 are evenly distributed along the circumference of the annular plate 421. The vibration sensors 46 collect the vibration signals at different positions of the annular plate 421. Based on the fluid-structure interaction dynamics principle, the flow state is analyzed through modal identification to perform a comprehensive diagnosis of the fluid flow state and achieve refined detection. The core is a technical method of deriving the fluid flow state through the spatial correlation of the vibration signals respectively collected by the plurality of vibration sensors 46 and the changes in modal parameters (such as frequency, damping, vibration mode, etc.). This is a well-known technology in the art, and the present application will not elaborate on it here.

[0059] In the appendix of the present applicationFigure 3 In the illustrated manner, taking the example of evenly arranging four vibration sensors 46 circumferentially on the ring plate 421 for exemplary illustration, of course, it does not constitute a limitation to the present application. Those skilled in the art can adaptively adjust the number or position of the vibration sensors 46 according to factors such as spatial position and the structural characteristics of the perforated plate structure 42.

[0060] For the operation of the evaporative cooling system, after the working fluid undergoes phase change and heat exchange, it converges to the radial liquid return section of the liquid return pipe 3. Generally speaking, the radial liquid return section of the liquid return pipe 3 is filled with fluid within its cross-section (because the fluid accumulates here). Therefore, when obtaining vibration signals through multiple vibration sensors 46, if the evaporative cooling system operates normally, the modal parameters of the vibration signals collected by multiple vibration sensors 46 are generally consistent. When one or more of the vibration signals collected by multiple vibration sensors 46 significantly differ from other vibration signals, it indicates that the fluid may not fill the pipe cross-section, resulting in differences in vibration signals. At this time, abnormal phenomena such as blockage or liquid shortage may occur in the loop.

[0061] Refer to Figure 2 , both ends of the main body portion 41 are connected to the liquid return pipe 3 through a flange 5. In this way, on the basis of realizing the sealing of the fluid state detection device 4 and the liquid return pipe 3, the connection stability can also be improved, reducing the risk of loosening of the pipeline connection part caused by the high-speed rotation of the rotor.

[0062] As above, by connecting the fluid state detection device in the radial liquid return section of the liquid return pipe 3 of the evaporative cooling system, the present application not only realizes the online detection of fluid flow rate, but also can reduce the pressure at the inlet of the hollow wire of the rotor excitation winding 100, thereby being beneficial to improving the cooling efficiency of the evaporative cooling system.

[0063] On the other hand, the present application integrates the conductivity detection element 45 and the vibration sensor 46 into the perforated plate structure 42, realizing the synchronous detection of fluid flow rate, moisture content, and fluid flow state on the same detection device, improving the integration degree of the detection device.

[0064] The present application also discloses a motor, which includes the evaporative cooling system in any of the above embodiments. The evaporative cooling system is arranged in the rotor of the motor, and its gas collecting pipe 2 and liquid return pipe 3 are communicated with the hollow wires in the excitation winding 100 of the electronics to form a circulation loop.

[0065] It should be noted that although in the above embodiments of the present application, the evaporative cooling system is used in the motor for exemplary illustration, it does not constitute a limitation to the present application. In some other scenarios that require cooling, the gas collecting pipe 2 and the liquid return pipe 3 of the evaporative cooling system can be connected to the cooling pipelines configured with the corresponding heat sources to form a circulation loop.

[0066] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.

Claims

1. A fluid state detection device, which is used to be connected and arranged in an evaporative cooling system, characterized in that: The detection device comprises: A main body (41) having a chamber (200) therein for fluid to pass through; a porous plate structure (42) connected to the main body (41), wherein the porous plate structure (42) is located in the chamber (200) so that a fluid can pass through the porous plate structure (42); A pressure detection element (43) for detecting the fluid pressure on both sides of the porous plate structure (42); A data processing module (44) is communicatively connected to the pressure detection element (43), and the data processing module (44) determines the fluid flow rate according to the detection value of the pressure detection element (43).

2. The detection device according to claim 1, characterized in that: The detection device also includes: The conductivity detection element (45) has a detection end extending into the chamber (200) and is used to detect the conductivity of the fluid.

3. The detection device according to claim 2, characterized in that: The conductivity detection element (45) is embedded in the porous plate structure (42), and the detection end of the conductivity measurement element extends into the pores of the porous plate structure (42).

4. The detection device according to any one of claims 1 to 3, characterized in that: A ring plate (421) is extended around the porous plate structure (42), the ring plate (421) extends out of the outside of the main body (41) and is sealed to the main body (41), and the data processing module (44) is arranged on the ring plate (421).

5. The detection device according to claim 4, characterized in that: A vibration sensor (46) is embedded in the ring plate (421), and the vibration sensor (46) is used to detect the vibration amount of the porous plate structure (42); The data processing module (44) is also in communication connection with the vibration sensor (46), and the data processing module (44) determines the flow state of the fluid according to the detection value of the vibration sensor (46).

6. The detection device according to claim 5, characterized in that: A plurality of vibration sensors (46) are evenly distributed along the circumference of the ring plate (421).

7. An evaporative cooling system, characterized in that: include: A condenser (1) and an air collecting pipe (2) and a liquid return pipe (3) respectively connected to both ends of the condenser (1), wherein the air collecting pipe (2) and the liquid return pipe (3) are both connected to a cooling pipeline configured for a heat source to form a circulation loop; The detection device according to any one of claims 1 to 6 is connected and arranged in the liquid return pipe (3).

8. The evaporative cooling system according to claim 7, characterized in that Both ends of the main body (41) are connected to the liquid return pipe (3) via flanges (5).

9. A motor, characterized in that: include: A rotor comprising an excitation winding (100), wherein the excitation winding (100) has a hollow conductor; The evaporative cooling system according to claim 7 or 8 is arranged on the rotor to cool the excitation winding (100), and the gas collecting pipe (2) and the liquid return pipe (3) are both connected to the hollow conductor to form the circulation loop.

10. The motor according to claim 9, characterized in that The liquid return pipe (3) comprises an axial liquid return section extending along the axial direction of the rotor and a radial liquid return section extending along the radial direction of the rotor, and the detection device is arranged in communication with the radial liquid return section.

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