In the field of industrial equipment condition monitoring, the performance of vibration sensors directly determines the accuracy and reliability of fault diagnosis. As a magnetoelectric speed sensor designed for rotating machinery, the SDJ-SC-2H vibration sensor has a flat response capability in the frequency range of 0.5-100Hz, which makes it show excellent adaptability in vibration monitoring of key equipment such as turbines and compressors. This technical feature not only broadens the application boundaries of traditional vibration sensors, but also provides a reliable guarantee for the accurate capture of low-frequency vibration signals.

1. Mechanical structure design: Coordinated optimization of inertial mass and spring system

The core principle of the vibration sensor SDJ-SC-2H is based on magnetoelectric induction, and its internal structure consists of a magnetic circuit system, an inertial mass block and a spring damping device. When the device under test vibrates, the inertial mass block is displaced relative to the fixed magnet due to inertia, cutting the magnetic lines of force and inducing a voltage signal in the coil. This voltage is proportional to the vibration velocity, thereby realizing the measurement of the vibration velocity.

To achieve a flat response in the range of 0.5-100Hz, the mechanical structure design of the vibration probe is crucial. First, the mass of the inertial mass block and the stiffness of the spring need to be precisely matched. In the low frequency band (such as 0.5-5Hz), if the inertial mass block is too heavy or the spring stiffness is too large, the sensitivity of the sensor will drop significantly, resulting in signal attenuation; conversely, in the high frequency band, if the inertial mass block is too light or the spring stiffness is too small, it may cause resonance and cause signal distortion. The vibration sensor SDJ-SC-2H optimizes the dynamic characteristics of the inertial mass and the spring to suppress the resonance effect in the high frequency band while ensuring low-frequency sensitivity. For example, its natural frequency is designed to be about 10Hz, which is at the edge of the target frequency range, which can effectively capture low-frequency vibrations and avoid excessive interference in the high frequency band.

In addition, the damping coefficient of the spring damping system is also critical to the realization of flat response. Excessive damping will inhibit the dynamic response capability of the vibration sensor and cause low-frequency signal attenuation; while too low damping may cause oscillation of the mechanical system and affect measurement stability. The vibration sensor SDJ-SC-2H adopts a nonlinear damping design. Through material selection and structural optimization, it maintains stable damping characteristics in a wide frequency range, thereby reducing signal distortion.

2. Circuit design: signal conditioning and low-frequency compensation technology

Based on the mechanical structure, the circuit design of the vibration velocity sensor SDJ-SC-2H further enhances its flat response capability in the range of 0.5-100Hz. The voltage signal output by the magnetoelectric sensor usually contains noise and nonlinear components, which need to be filtered, amplified and calibrated by the signal conditioning circuit.

In response to the signal attenuation problem in the low-frequency band, the vibration probe SDJ-SC-2H introduces a low-frequency compensation circuit. The sensitivity of traditional magnetoelectric sensors in the low-frequency band decreases as the frequency decreases, and its output voltage is proportional to the frequency. To eliminate this dependency, the built-in circuit of the sensor dynamically adjusts the gain of the low-frequency signal through a proportional-integral control algorithm. For example, in the range of 0.5-5Hz, the circuit automatically increases the gain to compensate for the insufficient sensitivity of the mechanical structure, so that the output voltage is closer to the actual vibration velocity value. This compensation mechanism does not require an external power supply and is completely dependent on the electronic components inside the sensor, which simplifies the installation process and improves the reliability of the system.

In the high frequency band, the vibration sensor SDJ-SC-2H suppresses the interference of parasitic signals through a high-pass filter. Although the nominal frequency response of the SDJ-SC-2H is 5-1kHz, its flat response characteristics below 100Hz enable it to accurately capture low-frequency vibration characteristics, while the signal attenuation in the high frequency band is limited to an acceptable range (error less than 4%). This design not only meets the needs of low-frequency monitoring, but also avoids excessive amplification of high-frequency noise.

3. Material selection: environmental adaptability and long-term stability

The material selection of the vibration velocity sensor SDJ-SC-2H also plays a key role in its wide-band response capability. The sensor housing is made of high-strength stainless steel and can work stably in the temperature range of -30℃ to 120℃. This weather-resistant design ensures the long-term reliability of the sensor in complex industrial environments (such as high-temperature steam and high-humidity workshops).

At the same time, the coil of the sensor is wound with corrosion-resistant enameled wire, and the insulation performance is enhanced by a vacuum impregnation process. Together, these measures ensure the output consistency of the sensor over a wide frequency range, and maintain stable sensitivity even in long-term operation.

In vibration monitoring of rotating machinery such as steam turbines, fans, and pumps, the 0.5-100Hz flat response capability of the vibration probe SDJ-SC-2H has significant advantages. For example, during the startup and shutdown of a steam turbine rotor, its vibration frequency may be lower than 5Hz, and at this time, traditional sensors are difficult to capture effective signals due to insufficient sensitivity. The vibration transmitter SDJ-SC-2H uses low-frequency compensation technology to clearly record the weak vibrations at the beginning of the rotor startup, providing data support for engineers to analyze dynamic processes such as rotor thermal expansion and bearing oil film establishment.

When looking for high-quality, reliable vibration sensor, YOYIK is undoubtedly a choice worth considering. The company specializes in providing a variety of power equipment including steam turbine accessories, and has won wide acclaim for its high-quality products and services. For more information or inquiries, please contact the customer service below:
E-mail: sales@yoyik.com
Tel: +86-838-2226655
Whatsapp: +86-13618105229

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