Motor shaft voltage acquisition device

Abstract

The invention provides a motor shaft voltage acquisition device, which belongs to the technical field of electric power engineering and comprises an electricity leading part and a test cable. The electricity leading part comprises a rotating side, and the rotating side is connected with a main shaft of a motor, so that the main shaft can drive the rotating side to rotate; the test cable is used for being electrically connected with a bearing inner ring of a motor and the rotating side so that electrical parameters of the bearing inner ring can be transmitted to the rotating side through the test cable and transmitted out through the rotating side. According to the invention, it is ensured that the acquired shaft voltage signal is consistent with the shaft voltage state during actual operation of the motor, the actual shaft voltage level in the working process of the motor is truly reflected, and the shaft voltage acquisition precision is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power engineering, in particular to a motor shaft voltage acquisition device. BACKGROUND

[0002] The shaft voltage is the voltage generated on the motor shaft during the operation of the motor or generator. When the shaft voltage generated by the motor is higher than the withstand voltage value of the bearing oil film, EDM breakdown discharge occurs through the bearing inner and outer ring raceways, balls and oil film, resulting in shaft current, causing the surface metal material of the "inner and outer ring raceways" and "balls" to melt, thereby generating concave and convex pits.

[0003] With the further deepening of the high pressure of the new energy market, the performance of new energy vehicles is improved, but it also brings a series of problems such as the increase of shaft voltage, the aggravation of bearing electric corrosion risk and the generation of high-frequency shaft current. Therefore, how to conveniently and efficiently, accurately and safely acquire shaft electric data during the development of electric drive has become a top priority for researchers to estimate the risk of bearing electric corrosion and ensure the safety and comfort of vehicle driving.

[0004] As an advanced form of new energy vehicle driving motor, distributed electric drive is gradually changing the direction of industry technology and market pattern. The distributed electric drive system realizes more efficient power transmission and more flexible vehicle control by dispersing the power source to each wheel of the vehicle, greatly enhancing the controllability and stability of the vehicle. The distributed electric drive system has the characteristics of high integration, multiple motors running at the same time, and complex shaft voltage sources, making the measurement of shaft voltage extremely challenging.

[0005] The prior art proposes a motor shaft voltage measuring device, which uses a single-point conductive fiber bundle and a multi-point contact with a non-conductive ring carbon fiber bundle. Both of them can only test the shaft voltage at the proximal end, cannot truly reflect the actual shaft voltage level of the bearing inner ring, and the motor shaft and the conductive fiber bundle or carbon fiber bundle have relative motion during the test process. The change in the contact state of the conductive fiber bundle and the carbon fiber bundle causes the test data to change. SUMMARY

[0006] Therefore, the purpose of the embodiments of the present application is to provide a motor shaft voltage acquisition device that can improve the problem that the prior art cannot truly reflect the actual shaft voltage level of the bearing inner ring, and the motor shaft and the conductive fiber bundle or carbon fiber bundle have relative motion during the test process, and the change in the contact state of the conductive fiber bundle and the carbon fiber bundle causes the test data to change.

[0007] To achieve the above technical purpose, the technical scheme adopted by the present application is as follows:

[0008] In a first aspect, the embodiments of the present application provide a motor shaft voltage acquisition device, comprising an electricity leading part and a test cable.

[0009] The electricity introduction part comprises a rotating side, which is used to be connected with the main shaft of the motor, so that the main shaft can drive the rotating side to rotate;

[0010] The test cable is electrically connected with the inner ring of the bearing and the rotating side of the electricity introduction part, so that the electrical parameter of the inner ring of the bearing can be transmitted to the rotating side through the test cable and transmitted out through the rotating side.

[0011] According to the above technical features, when the motor is running, the main shaft can rotate synchronously with the rotating side of the electricity introduction part. The shaft voltage signal generated by the high-speed rotation of the inner ring of the bearing is transmitted to the rotating side rotating at the same speed through the test cable and transmitted out through the rotating side, thereby completing. Therefore, since the test cable can be directly connected with the inner ring of the bearing, the voltage of the inner ring of the bearing can be measured in real time and accurately. At the same time, since the inner ring of the bearing and the rotating side are driven to rotate by the main shaft, the test cable is connected with both of them, so the test cable can rotate synchronously with the main shaft, and the shaft voltage can be collected when the motor is working. The collected shaft voltage reflects the actual shaft voltage when the motor is working, and the collection accuracy of the shaft voltage is improved.

[0012] Further, the test cable is arranged inside the main shaft.

[0013] According to the above technical features, the test cable is arranged inside the main shaft, which ensures that the test cable moves completely synchronously with the main shaft, further ensures the accuracy of the test data, and at the same time, the test cable is hidden inside the main shaft, which does not occupy additional space outside the motor, so that the overall structure is more compact.

[0014] Further, the main shaft is provided with a mounting hole at a position corresponding to the inner ring of the bearing, and the test cable passes through the mounting hole to be electrically connected with the inner ring of the bearing.

[0015] According to the above technical features, the position of the mounting hole corresponds to the inner ring of the bearing, so that the test cable can form a point contact type electrical connection with the inner ring of the bearing through the mounting hole, which is convenient for directly collecting the electrical parameter of the inner ring of the bearing.

[0016] Further, a coupling is further included, the rotating side is connected with the main shaft through the coupling, and the test cable is arranged inside the coupling.

[0017] According to the above technical means, the coupling can compensate for the deviation of the installation coaxiality between the main shaft and the rotating side, and transmit torque through elastic or rigid connection structure, so as to avoid the aggravation of the slip ring wear caused by the misalignment of the shaft system. The test cable is arranged inside the coupling, which further prolongs the protection path of signal transmission, and at the same time, the rigid structure of the coupling provides additional support for the test cable, prevents the cable from shaking due to centrifugal force during high-speed rotation, and ensures the stability of signal transmission.

[0018] Further, the motor shaft voltage acquisition device further comprises a fixed support fixed on the motor, and the coupling is fixed on the fixed support.

[0019] Further, the power lead part is fixed on the coupling.

[0020] Further, the number of the test cables is equal to the number of the bearing inner rings, and the test cables correspond to the bearing inner rings one by one.

[0021] According to the above technical means, the distributed acquisition of the electrical parameters of the bearing inner rings is realized, and the shaft voltage signals of multiple bearings can be synchronously acquired. Compared with single-channel testing, more comprehensive motor operation state data can be provided.

[0022] Further, the rotating side is provided with a circuit board, and the test cables are electrically connected with the circuit board.

[0023] Further, the test cables are welded with the main shaft.

[0024] Further, the power lead part is a slip ring.

[0025] The application adopting the above technical solution has the following advantages:

[0026] In the technical solution provided in the application, when the motor enters the running state, the main shaft drives the rotating side of the power lead part to realize synchronous rotation, and the rotating side and the power lead part always maintain the same rotating speed and do not have relative motion deviation. In this process, the bearing inner ring rotating at a high speed with the main shaft generates a shaft voltage signal, and the test cable arranged in advance can directly acquire the original shaft voltage signal of the bearing inner ring and stably transmit the signal to the rotating side also in the synchronous rotating state, and then the signal is converted by the stator of the rotating side. Therefore, the characteristic that the test cable rotates synchronously with the main shaft enables the test cable to continuously acquire the shaft voltage signal in the dynamic process of the normal operation of the motor, rather than only acquiring data in the static state, so that the acquired shaft voltage signal is consistent with the shaft voltage state of the actual operation of the motor, truly reflects the actual shaft voltage level in the operation process of the motor, improves the accuracy of the acquisition of the shaft voltage, and avoids the problem that the change of the contact state of the conductive fiber bundle and the carbon fiber bundle causes the change of the test data. BRIEF DESCRIPTION OF DRAWINGS

[0027] The application can be further illustrated by the non-limiting embodiments shown in the accompanying drawings. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be considered as limiting the scope, and other related drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The structural schematic diagram provided in the application.

[0029] Figure 2 The drawings provided in the present application Figure 1 The local enlarged view of part B in the present application.

[0030] Figure 3 The drawings provided in the present application Figure 1 The local enlarged view of part C in the present application.

[0031] Figure 4 The arrangement schematic view of test cable I provided in the present application.

[0032] Figure legend: 1-main shaft, 2-front end cover, 3-first bearing, 301-first bearing inner ring, 4-box body, 5-rotor, 6-stator, 7-second bearing, 701-second bearing inner ring, 8-rear end cover, 9-fixed support, 10-coupling, 11-test cable I, 12-test cable II, 13-circuit board, 14-electricity leading part, 15-mounting hole. DETAILED DESCRIPTION

[0033] In order to make the ordinary person skilled in the art better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings.

[0034] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in other than the order illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Instead, they are merely examples of apparatuses and methods consistent with some aspects of the present application as detailed in the appended claims.

[0035] In the embodiments of the present application, the words "exemplary", "such as" or "for example" are used to mean an example, an illustration or description. Any embodiment or design solution described as "exemplary", "such as" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of "exemplary", "such as" or "for example" is intended to present the relevant concept in a specific manner.

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, not all the embodiments.

[0037] The embodiment provides a motor shaft voltage acquisition device. The device acquires the electric parameters of a bearing inner ring, and then determines the shaft voltage. It can be understood that the motor is applied to a new energy vehicle. Before the motor is installed on the vehicle, a bench test needs to be performed. The bench test is used to acquire the shaft voltage of the motor, and the corrosion of the bearing is determined according to the shaft voltage.

[0038] Exemplarily, the motor in the embodiment comprises a main shaft 1, a front end cover 2, a first bearing 3, a box body 4, a rotor 5, a stator 6, a second bearing 7 and a rear end cover 8.

[0039] The front end cover 2 can be made of high-strength cast iron, and a precise bearing mounting groove is formed in the inner side of the front end cover 2, which is used for fixing the outer ring of the first bearing 3. Meanwhile, the front end cover 2 is tightly connected with the front end flange surface of the box body 4 through bolts, thereby providing reliable structural support for the front end of the motor and avoiding displacement of components caused by vibration during operation.

[0040] The first bearing 3 is a deep groove ball bearing, which comprises an inner ring and an outer ring. In the embodiment, the inner ring is defined as a first bearing inner ring 301, and the first bearing inner ring 301 is in interference fit with the front end journal of the main shaft 1. The outer ring of the first bearing 3 is in transition fit with the bearing mounting groove of the front end cover 2. During operation of the motor, the first bearing 3 can effectively transmit the radial load and part of the axial load of the rotor 5 to the front end cover 2.

[0041] The box body 4 is the core support frame of the motor, which is integrally formed by cast aluminum. The box body 4 not only has the advantage of light weight, but also has good heat dissipation performance. The internal cavity of the box body 4 provides installation space for the stator 6 and the rotor 5. Uniformly distributed stator slots are formed on the inner wall of the cavity, which are used for embedding the iron core and winding of the stator 6. In addition, the front end and the rear end of the box body 4 are respectively processed with flange surfaces matched with the front end cover 2 and the rear end cover 8, so as to ensure the coaxiality and sealing performance of the assembled components.

[0042] The rotor 5 is used to generate induced current under the induction of the stator magnetic field, and then form an electromagnetic torque to drive the main shaft 1 to rotate. The main shaft 1 is made of high-strength alloy steel, and the two ends are matched with the first bearing 3 and the second bearing 7 respectively. The front end is usually designed with a key groove or a flange, which is used for connecting the load and realizing power transmission.

[0043] The stator 6 is a fixed electromagnetic component of the motor, which maintains a certain air gap with the rotor 5 and together forms an electromagnetic system of the motor. The stator 6 is composed of a stator core, a stator winding and a machine base. When the stator winding is connected with three-phase alternating current, a rotating magnetic field is generated inside the motor. The rotating magnetic field cuts the rotor winding, so that the rotor generates induced current. Then the rotor is affected by electromagnetic force in the magnetic field, and rotates to realize the conversion of electric energy into mechanical energy.

[0044] The second bearing 7 is the same model as the first bearing 3 and has complementary functions. Its outer ring is fixed in the bearing mounting groove of the rear end cover 8, and its inner ring is interference-fitted with the rear end journal of the main shaft 1. During motor operation, the second bearing 7 mainly bears the rear radial load and the remaining axial load of the second main shaft 1. Together with the first bearing 3, it ensures the coaxiality of the rotor, prevents radial runout or axial movement of the rotor due to uneven force at both ends, and further reduces the frictional resistance of the rotor during rotation, ensuring the smooth operation and low noise characteristics of the motor.

[0045] The rear cover 8 is similar in structure and material to the front cover 2. It is connected to the rear flange of the housing 4 by bolts to form the rear sealing and support structure of the motor. The center of the rear cover 8 is also machined with a bearing mounting groove for fixing the outer ring of the second bearing 7.

[0046] For the motors of the aforementioned types of new energy vehicles, existing technologies often employ a handheld main test bar and a secondary test bar, using carbon brushes or copper brushes to test the shaft voltage. Data is collected by connecting a voltmeter via wires on the test bar. Although this testing method is simple in structure, it has low testing safety, and the inconsistent contact pressure of the handheld test bar results in low accuracy of the test data.

[0047] In other existing technologies, an insulated conductive ring and multiple bundles of carbon fiber brushes are used in combination to measure the near-end bearing shaft voltage level. However, this method has the problem that there must be a certain physical distance between the test conductive ring and the bearing, which makes the test data unable to reflect the true shaft voltage level. At the same time, the carbon fiber of the insulated conductive ring has internal resistance (5-7 ohms), and during operation, the breakage of the carbon fiber and the contact state with the motor shaft will cause changes in the resistance of the insulated conductive ring. Based on the above characteristics, this test method cannot be used to test the motor shaft current.

[0048] Therefore, based on the aforementioned shortcomings of the existing technology, such as Figure 1 and Figure 2 As shown, this application proposes a data acquisition device including an electrical lead 14, a test cable I11, and a test cable II 12.

[0049] The power supply part 14 includes a rotating side (not shown in the figure) and a fixed side (not shown in the figure). The rotating side and the fixed side are connected and communicate with each other. The rotating side is located in the inner ring and the fixed side is located in the outer ring. The rotating side can rotate relative to the fixed side. In this embodiment, the rotating side is connected to the end of the motor spindle 1 so that the spindle 1 can drive the rotating side to rotate.

[0050] Test cable I11 is electrically connected to both the inner ring 301 of the first bearing and the rotating side, so that the electrical parameters of the inner ring 301 of the first bearing can be transmitted to the rotating side through test cable I11. In this embodiment, one end of test cable I11 is electrically connected to the inner ring 301 of the first bearing and the other end is electrically connected to the rotating side. One end of test cable II 12 is electrically connected to the inner ring 701 of the second bearing and the other end is electrically connected to the rotating side, so that the electrical parameters of the inner ring 701 of the second bearing can be transmitted to the rotating side through test cable II 12.

[0051] The current-leading part 14 in this embodiment is an electrical component that enables continuous transmission of power and signals in rotating equipment. Its core structure consists of a rotating side and a fixed side, forming a conductive path through elastic contact or rolling overlap, thus solving the problem of wire entanglement during rotation. Taking the test cable I11 as an example, both ends of the test cable I11 are connected to the inner ring 301 of the first bearing and the rotating side, respectively. When the main shaft 1 rotates under the drive of the rotor 5, the main shaft 1 drives the outer ring 301 of the first bearing and the rotating side to rotate synchronously. The test cable I11 can also rotate synchronously with the parts connected at both ends, enabling synchronous measurement of electrical parameters of the motor during operation and improving the accuracy of shaft voltage measurement. Simultaneously, since the test cable I11 is directly electrically connected to the inner ring 301 of the first bearing, the voltage signal of the inner ring 301 can be directly acquired, ensuring the accuracy of the test data, avoiding signal attenuation, and ensuring that the shaft voltage waveform is accurately transmitted to the current-leading part 14. In this embodiment, the current-leading part 14 can be a slip ring.

[0052] After the electrical parameters of the inner ring 301 of the first bearing are transmitted to the rotating side through the test cable I11, the rotating side then transmits the electrical parameters to the fixed side of the current-inducing part 14, and finally the fixed side transmits the electrical parameters to the analysis module. The analysis module can determine the corrosion status of the bearing based on the electrical parameters and the built-in algorithm.

[0053] The electrical parameters in this embodiment can be voltage or current.

[0054] In this embodiment, a circuit board 13 is provided on the rotating side, and the test cable I11 is wrapped with Teflon to improve the wear resistance of the wire harness and ensure test stability. The test cable I11 and the circuit board 13 are fixed by welding for signal transmission. This connection method has a simple signal transmission path and high test safety.

[0055] Test cable II 12 is used to collect electrical parameters of the inner ring 701 of the second bearing. The technical effect is the same as above, so it will not be repeated here. Therefore, the following is used to explain the implementation of this device, and only test cable I11 is described.

[0056] In at least one embodiment, the test cable I11 passes through the interior of the spindle 1. Specifically, as shown... Figures 2-4As shown, the spindle 1 has a mounting hole 15 at a corresponding position on the inner ring 301 of the first bearing. The mounting hole 15 is connected to the central hole inside the spindle 1, and the central hole is parallel to the axial direction of the spindle 1. The spindle 1 can be hollow, in which case the central hole corresponds to the hollow part; the spindle 1 can also be solid, in which case the central hole is obtained by drilling a hole in the spindle 1. In this embodiment, the central hole is perpendicular to the mounting hole 15, and the test cable I11 passes through the mounting hole 15 and is electrically connected to the inner ring 301 of the first bearing.

[0057] Therefore, before assembling the motor, a mounting hole 15 is reserved on the spindle 1 at a position corresponding to the inner ring 301 of the first bearing. The test cable I11 enters the spindle 1 through the mounting hole 15 and then passes out from the other end of the spindle 1 to be electrically connected to the rotating side. In this embodiment, the end of the test cable I11 extends out of the mounting hole 15 and is connected to the spindle 1 through the interference fit of the first bearing 3, ensuring the connection stability between the test cable I11 and the inner ring 301 of the first bearing.

[0058] In this embodiment, the test cable I11 extends into the spindle 1 from the mounting hole 15 and passes through the spindle 1, achieving integrated synchronous movement with the spindle 1, that is, there is no relative movement between the two, which maximizes the accuracy of the test data.

[0059] Test cable I11 is threaded inside spindle 1, essentially encased and protected by the spindle 1. This structure creates a stable environment for test cable I11. The position, orientation, and wiring path of test cable 11 are fixed by spindle 1 after assembly and will not change due to the high-speed rotation of spindle 1. This avoids signal attenuation and impedance fluctuations caused by cable swaying and vibration. The absence of relative motion between test cable I11 and spindle 1 ensures that the physical path of signal transmission from the source to the acquisition port remains constant. This avoids signal propagation delay fluctuations caused by changes in the shape of test cable I11, thus guaranteeing the authenticity of the acquired dynamic signal in terms of timing and phase.

[0060] Understandably, the mounting hole corresponding to test cable II 12 is located on spindle 1 at the position corresponding to the inner ring of the second bearing.

[0061] In this embodiment, in order to improve the stability of the test cable I11, multiple welding points are provided in the axial direction of the spindle 1. The welding points are used to connect the spindle 1 and the test cable I11, which further improves the synchronization of the rotation of the test cable I11 and the spindle 1.

[0062] In this embodiment, as Figure 1 As shown, both the rotor 5 and the first bearing 3 are press-fitted into the front end cover 2, with the rotor 5 positioned closer to the current-injecting part 14 relative to the first bearing 3. This structure ensures that the test cable I11 remains in contact with the inner ring 301 of the first bearing.

[0063] like Figure 1 As shown, the device proposed in this embodiment also includes a coupling 10, with the rotating side connected to the main shaft 1 via the coupling 10. Test cables I11 and II 12 are both passed through the inside of the coupling 10. The portions of test cables I11 and II 12 that extend from the inside of the coupling 10 are soldered to the circuit board 3.

[0064] Coupling 10 provides physical protection for test cables I11 and II 12, isolating them from external rotating parts and preventing cable breakage or wear due to swinging, tangling, or scraping against surrounding structures during high-speed rotation. Simultaneously, this layout optimizes the spatial structure, preventing external overhead wires from interfering with equipment layout and operational safety. Furthermore, it reduces signal noise and fluctuations introduced by vibration and positional changes.

[0065] It is understandable that after passing through the main shaft 1, since the coupling 10 and the main shaft 1 are centered at the same degree, it can be directly inserted into the coupling 10.

[0066] The coupling 10 is used to transmit the torque of the main shaft 1, thereby enabling the main shaft 1 to drive the rotation of the rotating side. It is understood that although the coupling 10, test cable I11, and test cable II 12 are all connected to the rotating side, test cables I11 and II 12 are connected to the circuit board 13 on the rotating side. Structurally, the solder joints and wiring of test cables I11 and II 12 are properly confined within the rotating side where the circuit board 13 is located, or within a specific cavity. The connection interface of the coupling 10 is located in the power output area at the end of the rotating side, ensuring that test cables I11 and II 12 operate within their respective channels, without crossing or interfering with each other.

[0067] In this embodiment, as Figure 1 As shown, a fixed support 9 is also fixed on the motor. The fixed support 9 has a π-shaped structure and is fixed on the rear end cover 8. The coupling 10 is bolted to the fixed support 9, and the power supply part 14 is inserted into the coupling 10 and fixed by bolts.

[0068] It is understood that the acquisition device disclosed in this embodiment is used to acquire the shaft voltage of the motor under test. Therefore, after sampling of the motor under test is completed, the motor under test is disassembled, and the main shaft of the motor under test is assembled with test cable I11 and test cable II 12 before the motor is assembled. The assembly method of the device in this embodiment can be as follows:

[0069] Step S1: Assembly of housing components: Heat-fit the stator 6 into the housing 4;

[0070] S2: Rotor 5 assembly integration. Rotor 5 is interference-fitted to spindle 1;

[0071] After welding and fixing test cable I11 and test cable II 12 through the corresponding mounting holes, they are passed out from the non-drive end of the motor shaft.

[0072] Press the second bearing 7 into the spindle 1 to ensure that the test cable I11 remains in contact with the inner ring 301 of the first bearing.

[0073] Step S3: Assembly of front cover 2. Install the first bearing 3 into the front cover 2, and then press the rotor 5 into the front cover 2, ensuring that the test cable II 12 remains in contact with the inner ring 701 of the second bearing;

[0074] Step S4: Assembly. Assemble the housing 4, front cover 2 and rear cover 8. Lead test cables I11 and II12 out from the spindle 1, pass them through the coupling 10 and fix them to the circuit board 13 by welding to complete signal transmission;

[0075] The fixed support 9 is fixed to the rear end cover 8 by bolts, the coupling 10 is fixed to the fixed support 9 by bolts, and the electric lead part 14 is inserted into the coupling 10 and fixed by bolts.

[0076] Run the motor according to the test outline and collect the voltage waveforms of the first bearing 3 and the second bearing 7.

[0077] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electric machine shaft voltage acquisition device, characterized by The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft.

2. The motor shaft voltage acquisition apparatus according to claim 1, characterized by The test cable is arranged in the inside of the main shaft.

3. The motor shaft voltage acquisition apparatus according to claim 2, characterized by The test cable is arranged in the inside of the main shaft.

4. The motor shaft voltage acquisition apparatus according to claim 1, characterized by The test cable is arranged in the inside of the main shaft.

5. The motor shaft voltage acquisition apparatus according to claim 4, characterized by The test cable is arranged in the inside of the main shaft.

6. The motor shaft voltage acquisition apparatus according to claim 4, characterized by The test cable is arranged in the inside of the main shaft.

7. The motor shaft voltage harvesting device of claim 1, wherein, The test cable is arranged in the inside of the main shaft.

8. The motor shaft voltage harvesting device of claim 1, wherein, The test cable is arranged in the inside of the main shaft.

9. The motor shaft voltage harvesting device of claim 1, wherein, The test cable is arranged in the inside of the main shaft.

10. The motor shaft voltage harvesting device of any one of claims 1-9, wherein, The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged in the inside of the main shaft. The test cable is arranged

Images