Generator stator winding dynamic turn-to-turn short circuit fault detection method and device

Abstract

The invention discloses a generator stator winding dynamic turn-to-turn short circuit fault detection method and device, and relates to the technical field of generator state monitoring and fault diagnosis, and the method comprises the steps: measuring a generator rotor vibration signal in real time; transforming the vibration signal from a time domain signal to a frequency domain signal by using fast Fourier transform; and comparing the collected time domain signal and the converted frequency domain signal with each component of the frequency spectrum of the vibration signal under the normal condition, and judging whether the generator has a winding dynamic turn-to-turn short circuit fault or not. Whether the dynamic turn-to-turn short circuit fault of the stator winding occurs in the generator is identified by detecting the rotor vibration of the generator. The method is simple and easy to implement, overcomes the defects of winding dynamic turn-to-turn short circuit fault detection at present, is obvious in detection characteristic and good in effect, and provides reference for detection and diagnosis of generator stator winding dynamic turn-to-turn short circuit faults.

Description

Technical Field

[0001] The present invention relates to the technical field of generator state monitoring and fault diagnosis, and more particularly to a method and device for detecting dynamic inter-turn short-circuit fault of a generator stator winding. Background Art

[0002] At present, due to the aging of the insulation layer and the long-term complex mechanical and thermal stress, the stator winding of the generator has insulation danger points, which exist in the form of cracks, wear, etc. When there is a direct connection between the copper wires of different turns, a stator winding turn-to-turn short circuit fault will occur. In most current studies, the stator winding turn-to-turn short circuit mentioned is a steady-state winding turn-to-turn short circuit fault, and the insulation fault point of the short-circuited winding is permanently connected. But in fact, when the stator winding is under the action of electromagnetic force, intermittent or periodic contact will occur between the short-circuited turns. At this time, the generator is a dynamic stator winding turn-to-turn short circuit. Specifically, in the case of dynamic stator winding turn-to-turn short circuit, the short circuit fault does not persist. At some time, the stator winding is normal and no short circuit fault occurs. At another time, the short-circuited turns of the winding contact each other and a short circuit fault occurs. The dynamic stator winding turn-to-turn short circuit fault is an early development form of turn-to-turn short circuit fault, which is usually difficult to detect during the overhaul of the unit. After a long period of operation, the generator is likely to develop a steady-state stator winding inter-turn short-circuit fault, which will cause the three-phase current of the generator to be unbalanced and obvious vibration in the stator winding. At the same time, a large amount of heat will be generated, causing the temperature of the faulty coil to rise, eventually leading to insulation failure, affecting more coils to fail, and causing serious consequences such as generator shutdown.

[0003] In summary, discovering and handling faults in the early stages of their development can reduce economic losses caused by downtime and other problems. Therefore, how to detect dynamic inter-turn short-circuit faults in generator stator windings is an urgent problem that technicians in this field need to solve. Summary of the invention

[0004] In view of this, the present invention provides a method and device for detecting dynamic inter-turn short-circuit faults of stator windings of a generator to solve the problems existing in the background technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for detecting a dynamic inter-turn short-circuit fault of a generator stator winding, comprising:

[0007] Real-time measurement of generator rotor vibration signals;

[0008] The vibration signal is transformed from a time domain signal to a frequency domain signal using fast Fourier transform;

[0009] The collected time domain signal and the transformed frequency domain signal are compared with the frequency spectrum components of the vibration signal under normal conditions to determine whether the generator has a dynamic inter-turn short circuit fault in the stator winding.

[0010] Optionally, the real-time measurement of the generator rotor vibration signal is specifically:

[0011] An acceleration sensor is installed on the bearing seat of the generator rotor, and the rotor vibration signal is measured using the acceleration sensor.

[0012] Optionally, the determining whether a dynamic inter-turn short circuit fault of a stator winding of the generator occurs specifically includes:

[0013] Obtain the air gap magnetomotive force and air gap permeance per unit area of ​​the generator under normal operation and dynamic inter-turn short circuit fault of the stator winding;

[0014] The air gap flux density of the generator is obtained by multiplying the air gap magnetomotive force and the air gap permeance per unit area;

[0015] The magnetic pull per unit area is calculated based on the air gap magnetic flux density of the generator; and the unbalanced magnetic pull on the rotor is obtained by integrating the magnetic pull per unit area over the entire circumference;

[0016] When the unbalanced magnetic pull on the rotor is zero, the generator is in a normal state;

[0017] When the unbalanced magnetic pull on the rotor is not zero, a dynamic inter-turn short circuit fault of the stator winding occurs in the generator.

[0018] Optionally, the air gap magnetomotive force is specifically manifested as:

[0019]

[0020] Where ω is the electrical frequency, t is the time, I0 is the excitation current of the generator, K = 2qw c k wl τfL, q is the number of slots per pole and per phase, w c is the number of turns of the coil, qw c is the total number of turns of the stator winding parallel branches, k wl is the fundamental winding factor, τ is the pitch of the stator winding, f is the generator electrical frequency, and L is the length of the stator core; γ is the harmonic order, γ=1,3,5,7; η is the coefficient of the stator magnetomotive force relative to the rotor magnetomotive force; Ψ is the internal power factor angle of the generator, which is determined by the load characteristics; α m is the circumferential position angle of the air gap; β1 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is normal; β2 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is dynamically short-circuited; I fd1 and Ifd2 are the amplitudes of the first and second current harmonics generated in the field winding under the dynamic inter-turn short circuit of the stator winding, I fd1 =k1I0,I fd2 =k2I0, where k1 and k2 represent the short circuit coefficients.

[0021] Optionally, the air gap permeability per unit area is specifically expressed as:

[0022]

[0023] Where g0 is the average air gap length of the generator, μ0 is the air permeability, and Λ0 is the permeability constant per unit area of ​​the air gap.

[0024] Optionally, the generator air gap magnetic flux density is specifically expressed as:

[0025]

[0026] Optionally, the unbalanced magnetic pull on the rotor is specifically manifested in the following form:

[0027]

[0028] Where L is the length of the stator core and R is the radius of the outer surface of the rotor core.

[0029] Optionally, when the generator is in a normal state, the unbalanced magnetic pull on the rotor is expressed as:

[0030]

[0031] Optionally, when a dynamic inter-turn short circuit fault occurs in the stator winding of the generator, the unbalanced magnetic pull on the rotor is expressed as follows:

[0032]

[0033] A generator stator winding dynamic inter-turn short-circuit fault detection device comprises: a generator, a drive motor, a signal acquisition instrument, a host computer, an acceleration sensor, a short-circuit wiring board, a relay and a pulse generator;

[0034] The pulse generator, relay, short-circuit wiring board, generator and drive motor are connected in sequence;

[0035] An acceleration sensor is installed on the bearing seat of the generator rotor to measure the vibration signal of the generator rotor. The acceleration sensor is connected to a signal acquisition instrument, and the signal acquisition instrument is connected to a host computer.

[0036] It can be known from the above technical scheme that, compared with the prior art, the present invention discloses a method for detecting dynamic inter-turn short-circuit faults in the stator windings of a generator, including: real-time measurement of the vibration signal of the generator rotor; using fast Fourier transform to transform the vibration signal from a time domain signal to a frequency domain signal; comparing the collected time domain signal and the transformed frequency domain signal with each component of the spectrum of the vibration signal under normal conditions to determine whether the generator has a dynamic inter-turn short-circuit fault in the stator windings. The present invention identifies whether the generator has a dynamic inter-turn short-circuit fault in the stator windings by detecting the rotor vibration of the generator. The present invention is simple and easy to implement, which makes up for the current deficiencies in the detection of dynamic inter-turn short-circuit faults in the stator windings of generators. The detection features are obvious and the effect is good, which provides a reference for the detection and diagnosis of dynamic inter-turn short-circuit faults in the stator windings of generators. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0038] Figure 1 A vector diagram of the air gap magnetomotive force of the generator provided by the present invention under normal conditions;

[0039] Figure 2 A vector diagram of the air gap magnetomotive force of the generator stator winding under dynamic inter-turn short circuit provided by the present invention;

[0040] Figure 3 A schematic diagram of a short-circuit tap of a stator winding of a generator provided by the present invention;

[0041] Figure 4 A schematic diagram of a short-circuit wiring board provided by the present invention;

[0042] Figure 5 Schematic diagram of the connection between the short-circuit terminal block provided by the present invention and the stator A phase winding

[0043] Figure 6 A schematic diagram of the connection of the experimental platform provided by the present invention;

[0044] Figure 7 A flow chart for detecting a dynamic inter-turn short-circuit fault of a winding provided by the present invention;

[0045] The numbers in the figure are: 1. driving motor, 2. acceleration sensor, 3. generator, 4. relay, 5. pulse generator, 6. signal acquisition instrument, 7. host computer. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The embodiment of the present invention discloses a method for detecting a dynamic inter-turn short-circuit fault of a stator winding of a generator. The method measures the vibration signal of a generator rotor in real time and uses it as a diagnostic parameter, wherein the vibration signal is acquired by an acceleration sensor, and then the signal is converted into a spectrum signal by performing a fast Fourier transform (FFT). Then, the acquired time domain signal and the transformed frequency domain signal are compared with each component of the spectrum of the vibration signal under normal circumstances to determine whether a dynamic inter-turn short-circuit fault of a stator winding of the generator occurs.

[0048] like Figure 7 As shown, the specific steps of the method are as follows:

[0049] a. Install the acceleration sensor on the bearing seat of the generator rotor and build an experimental platform;

[0050] b. Use acceleration sensor to measure rotor vibration signal;

[0051] c. Use fast Fourier transform to transform the vibration signal from time domain signal to frequency domain signal;

[0052] d. Confirm the operation status of the generator by comparing the time domain and frequency domain, and determine whether the generator has a dynamic inter-turn short circuit fault in the stator winding;

[0053] In a specific embodiment, the force condition of the generator rotor is calculated by the following formulas, so as to determine the characteristic frequency component of the rotor vibration when a dynamic inter-turn short circuit fault occurs in the stator winding of the generator.

[0054] like Figure 6 As shown, an acceleration sensor is installed on the bearing seat of the generator rotor, and two acceleration sensors are installed in the horizontal and vertical directions of the radial directions of the two bearing seats to measure the vibration signal of the generator rotor. The acceleration sensor is connected to a signal acquisition instrument, and the signal acquisition instrument is connected to a host computer.

[0055] After measuring the vibration signal of the generator rotor through the acceleration sensor, the vibration signal is transformed from the time domain signal to the frequency domain signal using the FFT fast Fourier transform in the host computer to obtain the frequency domain signal of the rotor vibration, and the characteristic frequency amplitude from 0Hz to 300Hz is recorded;

[0056] The dynamic inter-turn short fault of the generator stator winding is judged by comparing the time domain and the frequency domain. The time domain signal collected previously is transformed by FFT, and the transformed frequency domain signal is compared with the spectrum components in the vibration signal data sample under normal conditions.

[0057] When the amplitude of the time domain waveform of the generator rotor vibration signal and the amplitude of each harmonic component in the spectrum increase, and the frequency corresponding to each harmonic in the spectrum diagram is one to six times the frequency, the generator has a dynamic inter-turn short fault in the stator winding, and the larger the amplitude of each corresponding frequency, the greater the degree of the dynamic inter-turn short fault in the stator winding.

[0058] The characteristic frequency of the rotor vibration before and after the dynamic inter-turn short fault of the stator winding of the generator is obtained by calculation, such as Figure 1 and Figure 2 As shown, E0 is the A-phase electromotive force, β1 is the angle between the air gap composite magnetomotive force and the rotor magnetomotive force under normal conditions, and β2 is the angle between the air gap composite magnetomotive force and the rotor magnetomotive force under dynamic inter-turn short circuit of the stator winding. Therefore, the expression of the air gap magnetomotive force of the generator under normal operation and when a dynamic inter-turn short circuit fault of the stator winding occurs is as follows:

[0059]

[0060] Where ω is the electrical frequency, t is the time, I0 is the excitation current of the generator, K = 2qw c k wl τfL, q is the number of slots per pole and per phase, w c is the number of turns of the coil, qw c is the total number of turns of the stator winding parallel branches, k wl is the fundamental winding factor, τ is the pitch of the stator winding, f is the generator electrical frequency, and L is the length of the stator core; γ is the harmonic order, γ=1,3,5,7; η is the coefficient of the stator magnetomotive force relative to the rotor magnetomotive force; Ψ is the internal power factor angle of the generator, which is determined by the load characteristics; α m is the circumferential position angle of the air gap; β1 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is normal; β2 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is dynamically short-circuited; I fd1 and I fd2 are the amplitudes of the first and second current harmonics generated in the field winding under the dynamic inter-turn short circuit of the stator winding, I fd1 =k1I0,I fd2 =k2I0, where k1 and k2 represent the short circuit coefficients.

[0061] Under the dynamic inter-turn short-circuit fault of the stator winding, the radial length of the air gap of the generator remains unchanged, and the permeance per unit area is inversely proportional to the radial length of the air gap. Therefore, the permeance per unit area can be expressed as the following formula:

[0062]

[0063] Where g0 is the average air gap length of the generator, μ0 is the air permeability, and Λ0 is the permeability constant per unit area of ​​the air gap.

[0064] The air gap flux density of the generator is obtained by multiplying the air gap magnetomotive force and the air gap permeance. The stator winding dynamic turn-to-turn short-circuit fault before and after can be expressed as:

[0065]

[0066] Under normal conditions, the air gap flux density of the generator contains only fundamental waves and odd harmonics. When a dynamic inter-turn short circuit fault occurs in the stator winding, the fundamental wave amplitude of the air gap flux density decreases, and even harmonics will appear in the air gap flux density.

[0067] The exciting force of rotor vibration is the unbalanced magnetic pull on the rotor, which is obtained by integrating the magnetic pull per unit area on the outer surface of the rotor over the entire circumference. The expression is as follows:

[0068]

[0069] Where L is the length of the stator core and R is the radius of the outer surface of the rotor core.

[0070] When the generator is in normal state, the unbalanced magnetic pull on the rotor is as follows:

[0071]

[0072] The unbalanced magnetic pulls on the generator rotor in the X and Y directions are both zero, so theoretically the generator rotor does not produce radial vibration under normal operating conditions.

[0073] When a dynamic inter-turn short circuit fault occurs in the stator winding of the generator, the unbalanced magnetic pull on the rotor is as follows:

[0074]

[0075] From the above formula, it can be seen that the unbalanced magnetic pull on the rotor contains DC components and the first, second, third, fourth, fifth, and sixth harmonics. The more severe the short circuit is, the greater the amplitude of each harmonic of the unbalanced magnetic pull is. Since the rotor vibration is a response to the unbalanced magnetic pull of the rotor, when a dynamic inter-turn short circuit fault occurs in the stator winding, the generator rotor will vibrate at frequencies of 1f, 2f, 3f, 4f, 5f, and 6f, and as the short circuit degree increases, the vibration amplitudes of different frequency components will increase significantly.

[0076] Install an acceleration sensor on the generator rotor bearing seat. When the motor is running smoothly, collect ten sets of rotor vibration acceleration signal data, perform FFT fast Fourier transform on these ten sets of data, obtain the frequency domain signal of the acceleration signal, and calculate the average value of the amplitude corresponding to the characteristic frequency of these ten sets of data to obtain the data sample of the rotor vibration acceleration signal. Compare it with the data sample of the rotor vibration acceleration signal under normal conditions to determine whether the generator has a dynamic inter-turn short circuit fault in the stator winding.

[0077] The experimental device is used to simulate the dynamic inter-turn short-circuit fault of the stator winding. Figure 3 It is a schematic diagram of the three-phase stator winding of the generator. Five groups of short-circuit taps are connected to one of the branches of each phase of the three-phase stator winding, namely tap A1: 0%, tap A2: 2%, tap A3: 4%, tap A4: 6% and tap A; tap B1: 0%, tap B2: 2%, tap B3: 4%, tap B4: 6% and tap B; tap C1: 0%, tap C2: 2%, tap C3: 4%, tap C4: 6% and tap C.

[0078] Figure 4 This is a schematic diagram of a short-circuit wiring board, on which five short connectors are arranged.

[0079] Figure 5 It is a schematic diagram of the connection between each short-circuit tap on the stator A phase winding and the short-circuit wiring board; the relay is connected to the short-circuit wiring board, and the simulation of inter-turn short-circuit faults of different degrees of the three-phase stator winding can be realized through the cooperation of the short-circuit wiring board and the short-circuit taps of the stator winding.

[0080] In the simulation of specific turn-to-turn short-circuit fault, taking phase A as an example, the relay connected to interfaces A1 and A2 of the short-circuit wiring board can simulate a 2% short-circuit between turns of the stator phase A winding; the relay connected to interfaces A1 and A3 of the short-circuit wiring board can simulate a 4% short-circuit between turns of the stator phase A winding; the relay connected to interfaces A1 and A4 of the short-circuit wiring board can simulate a 6% short-circuit between turns of the stator phase A winding.

[0081] The pulse generator is connected to the relay, which can generate pulse signals of different periods as needed. When the relay receives the pulse signal, it will open or close according to the period of the pulse signal. According to the above designed device, the simulation of dynamic inter-turn short-circuit fault of the stator winding of the generator with different degrees and accurate and controllable frequency can be realized. The vibration data of the rotor under different operating conditions of the generator is recorded and saved through the acceleration sensor and signal acquisition instrument.

[0082] A generator stator winding dynamic inter-turn short-circuit fault detection device, comprising: a generator 3, a drive motor 1, a signal acquisition instrument 6, a host computer 7, an acceleration sensor 2, a short-circuit wiring board, a relay 4 and a pulse generator 5;

[0083] The pulse generator 5, the relay 4, the short-circuit wiring board, the generator 3, and the drive motor 1 are connected in sequence;

[0084] An acceleration sensor 2 is installed on the bearing seat of the rotor of the generator 3, and two are installed in the horizontal and vertical directions of the radial directions of the two bearing seats to measure the vibration signal of the generator rotor. The acceleration sensor 2 is connected to the signal acquisition instrument 6, and the signal acquisition instrument 6 is connected to the host computer 7.

[0085] The pulse generator 5 is connected to the relay 4 and can generate pulse signals of different periods as needed. When the relay 4 receives the pulse signal, it will be opened or closed according to the period of the pulse signal. The device designed according to the above can achieve simulation of dynamic inter-turn short-circuit faults of the stator winding of the generator with different degrees and accurate and controllable frequency.

[0086] The present invention can effectively detect the dynamic inter-turn short-circuit fault of the stator winding, and designs a device to verify the accuracy of the detection method. The detection method can be used to timely diagnose and eliminate the fault, reducing economic losses caused by downtime and other problems.

[0087] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0088] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting dynamic inter-turn short-circuit faults in stator windings of a generator, characterized in that: include: Real-time measurement of generator rotor vibration signals; The vibration signal is transformed from a time domain signal to a frequency domain signal using fast Fourier transform; The collected time domain signal and the transformed frequency domain signal are compared with the frequency spectrum components of the vibration signal under normal conditions to determine whether the generator has a dynamic inter-turn short circuit fault in the stator winding.

2. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 1, characterized in that: The real-time measurement of the generator rotor vibration signal is specifically as follows: An acceleration sensor is installed on the bearing seat of the generator rotor, and the rotor vibration signal is measured using the acceleration sensor.

3. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 1, characterized in that: The step of judging whether a dynamic inter-turn short circuit fault of a stator winding of a generator occurs specifically includes: Obtain the air gap magnetomotive force and air gap permeance per unit area of ​​the generator under normal operation and dynamic inter-turn short circuit fault of the stator winding; The air gap flux density of the generator is obtained by multiplying the air gap magnetomotive force and the air gap permeance per unit area; The magnetic pull per unit area is calculated based on the air gap magnetic flux density of the generator; and the unbalanced magnetic pull on the rotor is obtained by integrating the magnetic pull per unit area over the entire circumference; When the unbalanced magnetic pull on the rotor is zero, the generator is in a normal state; When the unbalanced magnetic pull on the rotor is not zero, a dynamic inter-turn short circuit fault of the stator winding occurs in the generator.

4. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 3, characterized in that: The air gap magnetomotive force is specifically manifested as: Where ω is the electrical frequency, t is the time, I0 is the excitation current of the generator, K = 2qw c k wl τfL, q is the number of slots per pole and per phase, w c is the number of turns of the coil, qw c is the total number of turns of the stator winding parallel branches, k wl is the fundamental winding factor, τ is the pitch of the stator winding, f is the generator electrical frequency, and L is the length of the stator core; γ is the harmonic order, γ=1,3,5,7; η is the coefficient of the stator magnetomotive force relative to the rotor magnetomotive force; Ψ is the internal power factor angle of the generator, which is determined by the load characteristics; α m is the circumferential position angle of the air gap; β1 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is normal; β2 is the angle between the synthetic magnetomotive force of the air gap and the magnetomotive force of the rotor when the stator winding is dynamically short-circuited; I fd1 and I fd2 are the amplitudes of the first and second current harmonics generated in the excitation winding under the dynamic inter-turn short circuit of the stator winding, I fd1 =k1I0,I fd2 =k2I0, where k1 and k2 represent the short circuit coefficients.

5. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 4, characterized in that: The air gap permeability per unit area is specifically expressed as: Where g0 is the average air gap length of the generator, μ0 is the air permeability, and Λ0 is the permeability constant per unit area of ​​the air gap.

6. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 5, characterized in that: The generator air gap flux density is specifically expressed as:

7. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 1, characterized in that: The specific manifestation of the unbalanced magnetic pull on the rotor is: Where L is the length of the stator core and R is the radius of the outer surface of the rotor core.

8. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 7, characterized in that: When the generator is in normal state, the unbalanced magnetic pull on the rotor is as follows:

9. A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to claim 7, characterized in that: When a dynamic inter-turn short circuit fault occurs in the stator winding of the generator, the unbalanced magnetic pull on the rotor is as follows:

10. A generator stator winding dynamic turn-to-turn short-circuit fault detection device, characterized in that: A method for detecting dynamic inter-turn short-circuit faults of stator windings of a generator according to any one of claims 1 to 9 is applied, comprising: a generator, a drive motor, a signal acquisition instrument, a host computer, an acceleration sensor, a short-circuit wiring board, a relay and a pulse generator; The pulse generator, relay, short-circuit wiring board, generator and drive motor are connected in sequence; An acceleration sensor is installed on the bearing seat of the generator rotor to measure the vibration signal of the generator rotor. The acceleration sensor is connected to a signal acquisition instrument, and the signal acquisition instrument is connected to a host computer.

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