Motor monitoring system capable of synchronously detecting temperature and vibration
By employing optical path multiplexing and signal separation technology, and utilizing fiber optic sensors, synchronous detection of motor vibration and temperature is achieved. This solves the problem of the impact of temperature changes on vibration monitoring, realizes high-precision motor condition monitoring, and is suitable for complex industrial environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHANGJIAKOU CIGARETTE FACTORY
- Filing Date
- 2025-07-15
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, changes in ambient temperature affect vibration signals, leading to misjudgments or missed detections in motor vibration monitoring, making it difficult to achieve high-precision synchronous detection of vibration and temperature.
A broadband light source, optical circulator, temperature-sensitive optical device, and reflector connected by optical fiber are used to acquire temperature and vibration signals separately through optical path multiplexing and signal separation technology. High-precision synchronous detection is achieved by using Bragg fiber gratings and photoelectric detection modules.
It achieves high-precision, low-cost dual-parameter fiber optic sensing of temperature and vibration, resists cross-interference, and is suitable for monitoring motor vibration status in complex industrial environments, avoiding false alarms and missed alarms.
Smart Images
Figure CN224247145U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor vibration monitoring, and more specifically, to a motor monitoring system that simultaneously detects temperature and vibration. Background Technology
[0002] Electric motors are indispensable power devices in modern industry and daily life. However, motors face various failure risks during operation, among which stalled rotor is a common and extremely dangerous failure mode. Stalled rotor occurs when the motor rotor cannot rotate due to mechanical jamming, excessive load, or transmission mechanism failure, while the stator windings remain energized. In the stalled rotor state, the motor loses its back electromotive force, and a stall current far exceeding the rated value will flow through the stator windings. This huge current will generate severe overheating in a short time, causing the winding insulation layer to age and burn rapidly, leading to short circuits or even fires. Therefore, rapid, accurate, and reliable detection and protection against motor stalled rotor conditions are crucial for ensuring safe equipment operation, extending equipment life, and avoiding production losses and safety accidents.
[0003] The mechanical vibration characteristics of an electric motor differ fundamentally between normal operation and stalled operation. Under normal operation, motor vibration primarily originates from dynamic imbalance during rotor rotation, electromagnetic harmonics, vibration of bearing rolling elements, and gear meshing. The overall vibration amplitude is typically maintained at a low and stable level under normal operation. In stalled operation, when the motor stalls, the rotor stops rotating instantaneously. At this point, the primary vibration excitation source changes drastically; a huge electromagnetic pull continuously acts on the stationary rotor, attempting to pull it to rotate but failing, resulting in strong, high-amplitude electromagnetic vibration between the stator and rotor. The overall vibration amplitude under stalled operation typically increases significantly and sharply, far exceeding the level under normal operation. This significant and observable difference in vibration amplitude makes vibration monitoring an effective technical approach for detecting motor stall faults.
[0004] Based on the above characteristics, vibration sensors are used to collect vibration signals installed on the motor housing or key bearing housings. By analyzing the time-domain and frequency-domain characteristics of these signals, the operating status of the motor can be effectively reflected. By monitoring whether the vibration amplitude exceeds a preset threshold, it can be determined whether abnormal vibration exists. Therefore, vibration monitoring technology provides a direct and effective technical means for online, non-invasively determining whether a motor is in normal working condition.
[0005] While vibration monitoring for stalled motors has a theoretical basis and feasibility, a key challenge in practical application is that changes in ambient and operating temperatures significantly affect the amplitude of vibration signals. Temperature variations can cause thermal expansion and contraction of motor structural materials, altering their stiffness or damping characteristics. The sensor's sensitivity can also drift with temperature. These temperature effects can introduce vibration amplitude fluctuations unrelated to faults. For example, increased temperature might cause vibration amplitude to exceed a preset threshold, leading to a misjudgment of stalled motors or other faults. Conversely, decreased temperature might prevent the actual stalled vibration signal from reaching the alarm threshold, missing the protection window. Therefore, temperature monitoring is necessary to avoid these misjudgments and missed detections of motor vibrations caused by temperature influences. Utility Model Content
[0006] To overcome the shortcomings mentioned above, this invention aims to provide a motor monitoring system that simultaneously detects temperature and vibration, achieving high-precision synchronous detection of vibration and temperature.
[0007] This application provides a motor monitoring system for synchronously detecting temperature and vibration, including a broadband light source, an optical circulator, a temperature-sensitive optical device, and a fixture connected in sequence via optical fiber; the optical fiber extends to the outside of the fixture, and a reflective surface is also provided on this side for sensing vibration.
[0008] The motor vibration monitoring system also includes an optical fiber coupler, which has a first interface, a second interface, and a third interface. The third interface is connected to the optical circulator via an optical fiber. The optical fiber coupler also has two branches. One branch connects to a bandpass filter and a photoelectric detection module sequentially from the second interface via an optical fiber. One end of the photoelectric detection module is electrically connected to a microcontroller. The other branch connects to a spectrometer connected to the first interface of the optical fiber coupler.
[0009] The light emitted by the broadband light source enters the temperature-sensitive optical device through an optical circulator. The reflected light is split through an optical fiber coupler: one path demodulates the temperature signal through a spectrometer; the other path filters out the reflection peaks of the temperature-sensitive optical device through a bandpass filter, retaining only the vibration-related light signal generated by the reflecting surface.
[0010] As an improvement to the above solution, the photoelectric detection module includes a photodiode and an amplifier connected in sequence; the photodiode is electrically connected to the amplifier.
[0011] As an improvement to the above solution, the reflective surface is placed on the right side of the fixture, and the reflective surface is perpendicular to the optical fiber located on the right side of the fixture.
[0012] As an improvement to the above scheme, the optical fiber is a single-mode optical fiber.
[0013] As an improvement to the above solution, the optical fiber is fixed to the fixture.
[0014] As an improvement to the above scheme, the temperature-sensitive optical device is a Bragg fiber grating.
[0015] As an improvement to the above scheme, the temperature-sensitive optical device is a combination of a temperature-sensitive metal sheet and a Bragg fiber grating.
[0016] As an improvement to the above scheme, the reflecting surface is a plane or a curved surface.
[0017] As an improvement to the above solution, a counterweight ball is provided on the optical fiber located on the right side of the fixer.
[0018] Compared with the prior art, the beneficial effects of this utility model are:
[0019] By employing optical path multiplexing and signal separation technology, light emitted from a broadband light source enters the sensing fiber segment via an optical circulator. A temperature-sensitive optical device serves as the core sensing element, with its center wavelength of reflection spectrum being sensitive to temperature. The reflected light signal is split by an optical fiber coupler; one path enters a spectrometer to accurately acquire the temperature value, while the other path passes through a bandpass filter and a photoelectric detection module to obtain vibration information. This invention achieves high-precision, low-cost dual-parameter fiber optic sensing of temperature and vibration, enabling simultaneous detection of vibration and temperature. It has the advantage of resisting cross-interference and is suitable for monitoring the vibration status of motors in complex industrial environments, demonstrating strong engineering practicality. Attached Figure Description
[0020] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:
[0021] Figure 1 This is a schematic diagram of the overall structure of a specific embodiment of a motor monitoring system that simultaneously detects temperature and vibration.
[0022] Figure 2 This is a schematic diagram of the overall structure of a specific embodiment two of a motor monitoring system that simultaneously detects temperature and vibration.
[0023] Figure 3 This is a schematic diagram of the overall structure of a specific embodiment three of a motor monitoring system that simultaneously detects temperature and vibration.
[0024] Figure 4 This is a schematic diagram of the overall structure of a specific embodiment four of a motor monitoring system that simultaneously detects temperature and vibration.
[0025] In the diagram: 1. Broadband light source; 2. Optical circulator; 21. First port of optical circulator; 22. Second port of optical circulator; 23. Third port of optical circulator; 3. Temperature-sensitive optical device; 4. Fixer; 5. Reflector; 6. Fiber optic coupler; 61. First interface of fiber optic coupler; 62. Second interface of fiber optic coupler; 63. Third interface of fiber optic coupler; 7. Spectrometer; 8. Bandpass filter; 9. Photoelectric detection module; 91. Photodiode; 92. Amplifier; 10. Microcontroller; 11. Optical fiber; 12. Counterweight ball. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0027] Example 1
[0028] like Figure 1 As shown, a motor monitoring system for synchronously detecting temperature and vibration includes a broadband light source 1, an optical circulator 2, a temperature-sensitive optical device 3, a fixture 4, a reflective surface 5, an optical fiber coupler 6, a spectrometer 7, a bandpass filter 8, a photoelectric detection module 9, a microcontroller 10, and an optical fiber 11. The broadband light source 1 is connected to the first port 21 of the optical circulator; the temperature-sensitive optical device 3 is connected to the second port 22 of the optical circulator and the fixture 4; the third interface 63 of the optical fiber coupler is connected to the third port 23 of the optical circulator; the spectrometer 7 is connected to the first interface 61 of the optical fiber coupler; the bandpass filter 8 is connected to the second interface 62 of the optical fiber coupler; the bandpass filter 8 is connected to the photoelectric detection module 9; and the photoelectric detection module 9 is connected to the microcontroller 10.
[0029] The output of broadband light source 1 is fused to the first port 21 of the optical circulator via optical fiber 11 to provide a broadband optical signal. Broadband light source 1 is an ASE light source with a wavelength range of 1520–1620 nm and a power of 10 mW. Optical fiber 11 is a single-mode fiber with a diameter of 125 μm, a coating diameter of 245 μm, and a mode field diameter of 9.5 ± 0.5 μm at a wavelength of 1550 nm.
[0030] The second port 22 of the optical circulator is fused to one end of the temperature-sensitive optical device 3 via optical fiber 11. The temperature-sensitive optical device 3 employs a Bragg fiber grating with a wavelength of 1550 nm, a reflection bandwidth of 0.2 nm, a sensitivity temperature of approximately 10 pm / ℃, and a reflectivity greater than 90%. The fixture 4 is a metal support, on which the output optical fiber 11 of the temperature-sensitive optical device 3 is fixed using UV-cured adhesive for vibration sensing. The position of the fixture 4 limits the length of the suspended optical fiber 11 to accommodate applications in different vibration frequency bands.
[0031] The reflective surface 5 is located behind the fixture 4. The end face of the suspended optical fiber 11, which is fixed by the fixture 4, is aligned parallel to the reflective surface 5, and the spacing is finely adjusted to 50±2μm by laser.
[0032] The third port 23 of the optical circulator is connected to the third interface 63 of the fiber optic coupler via optical fiber 11, distributing the reflected light signal to different branches. The fiber optic coupler 6 is a 1*2 type fiber optic coupler with a splitting ratio of 50:50.
[0033] The first interface 61 of the fiber optic coupler is connected to the spectrometer 7 via fiber optic cable 11 to demodulate the wavelength shift of the Bragg fiber grating, thereby obtaining temperature parameters.
[0034] The second interface 62 of the fiber optic coupler is connected to the bandpass filter 8 via fiber optic cable 11 to filter stray light in non-target wavelength bands. The center wavelength of the bandpass filter 8 is 1540 nm, and its bandwidth is 15 nm. The output of the bandpass filter 8 is connected to the photoelectric detection module 9 to convert the optical signal into an electrical signal and extract the interference intensity and phase change.
[0035] The photoelectric detection module 9 includes a photodiode 91 and an amplifier 92. The photodiode 91 is an InGaAs photodiode with a response wavelength range of 1200–1700 nm. The amplifier 92 uses an AD8304ARUZ chip.
[0036] The output of the photoelectric detection module 9 is connected to the microcontroller 10 for real-time processing of electrical signals and extraction of vibration parameters. The microcontroller 10 uses an ARM Cortex-M4 chip and is electrically connected to the photoelectric detection module 9 through an analog-to-digital converter interface.
[0037] Its working principle is based on optical path multiplexing and signal demodulation technology:
[0038] The light emitted by the broadband light source 1 enters the sensing fiber 11 segment through the optical circulator 2. The temperature-sensitive optical device 3 serves as the core sensing element, and the center wavelength of its reflection spectrum is sensitive to temperature. The light emitted by the broadband light source 1 enters the temperature-sensitive optical device 3 through the optical circulator 2, and the reflected light passes through the optical circulator 2 again to reach the fiber coupler 6. The transmitted light is output to the reflecting surface 5 through the fiber 11, and after being reflected, it travels along the fiber 11, the temperature-sensitive optical device 3, and the optical circulator 2 to reach the fiber coupler 6. The light reaching the fiber coupler 6 enters the spectrometer 7 in one direction to analyze the wavelength shift caused by temperature, which can accurately obtain the temperature value. The other direction passes through the bandpass filter 8 to filter out the reflection peak of the temperature-sensitive optical device 3, retaining only the signal generated by the reflecting surface 5. This signal is demodulated by the photoelectric detection module 9 to obtain the vibration information.
[0039] This embodiment enables simultaneous detection of vibration and temperature, avoiding misjudgments and missed detections of motor vibration caused by temperature fluctuations. This application also boasts advantages such as resistance to cross-interference and high integration, making it suitable for monitoring motor vibration status in complex industrial environments.
[0040] Example 2
[0041] This embodiment 1 is basically the same as the above embodiment 1, except that:
[0042] like Figure 2 As shown, unlike specific embodiment 1, in this embodiment, a counterweight ball 12 is added to the optical fiber 11 after the fixer 4. The counterweight ball 12 is made of UV-curable adhesive. By increasing the inertial mass, the counterweight ball 12 amplifies the light intensity change caused by vibration, thereby significantly improving vibration detection, especially the sensitivity to micro-vibrations, and improving the signal-to-noise ratio. At the same time, the counterweight ball 12 lowers the natural frequency of the system, significantly enhancing the response capability to critical low-frequency vibrations. These improvements only apply to the vibration sensing part and are completely decoupled from the temperature measurement realized by the temperature-sensitive optical device 3, ensuring the reliability and measurement accuracy of the dual-parameter system in complex environments.
[0043] Example 3
[0044] This embodiment is basically the same as Embodiment 1 above, except that:
[0045] like Figure 3 As shown, unlike specific embodiment 1, the reflective surface 5 in this embodiment is curved. The advantage of making the reflective surface 5 curved is that it reduces the light divergence angle, and the reflected light can still be efficiently coupled back to the optical fiber 11, thereby improving the signal-to-noise ratio of subsequent circuit detection.
[0046] Example 4
[0047] This embodiment is basically the same as Embodiment 1 above, except that:
[0048] like Figure 4 As shown, unlike specific embodiment 1, in this embodiment, the temperature-sensitive optical device 3 is a temperature-sensitive metal sheet attached to a Bragg fiber grating. The core advantage of directly attaching the temperature-sensitive metal sheet to the Bragg fiber grating is to improve the sensitivity of temperature detection: the thermal expansion coefficient of the temperature-sensitive metal sheet is significantly higher than that of the Bragg fiber grating. When the ambient temperature changes, the temperature-sensitive metal sheet actively expands / contracts and applies additional mechanical strain to the Bragg fiber grating, thereby increasing the total wavelength shift of the Bragg fiber grating. At the same time, the high thermal conductivity of the temperature-sensitive metal sheet can accelerate thermal equilibrium. This structure utilizes the high temperature sensitivity of the temperature-sensitive metal sheet.
[0049] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A motor monitoring system for synchronously detecting temperature and vibration, characterized in that, It includes a broadband light source (1), an optical circulator (2), a temperature-sensitive optical device (3), and a fixture (4) connected in sequence via an optical fiber (11); the optical fiber (11) extends to the outside of the fixture (4), and a reflective surface (5) is also provided on this side. The motor monitoring system also includes an optical fiber coupler (6), which has a first interface (61), a second interface (62), and a third interface (63). The third interface (63) is connected to the optical circulator (2) via an optical fiber (11). The optical fiber coupler (6) is also connected to two branches. One branch is connected to a bandpass filter (8) and a photoelectric detection module (9) in sequence from the second interface (62) via an optical fiber (11). One end of the photoelectric detection module (9) is electrically connected to a microcontroller (10). The other branch is connected to a spectrometer (7) connected to the first interface (61) of the optical fiber coupler.
2. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The photoelectric detection module (9) includes a photodiode (91) and an amplifier (92) connected in sequence; the photodiode (91) and the amplifier (92) are electrically connected.
3. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The reflective surface (5) is positioned to the right of the fixture (4), and the reflective surface (5) is perpendicular to the optical fiber (11) located to the right of the fixture (4).
4. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The optical fiber (11) is a single-mode optical fiber.
5. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The optical fiber (11) is fixed to the fixture (4).
6. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The temperature-sensitive optical device (3) is a Bragg fiber grating.
7. The motor monitoring system for synchronously detecting temperature and vibration according to claim 6, characterized in that, The temperature-sensitive optical device (3) also includes a temperature-sensitive metal sheet attached to the Bragg fiber grating.
8. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, The reflecting surface (5) is either a plane or a curved surface.
9. The motor monitoring system for synchronously detecting temperature and vibration according to claim 1, characterized in that, A counterweight ball (12) is provided on the optical fiber (11) located on the right side of the fixture (4).