In the operation and maintenance system of rotating machinery, the bearing bush, as a core component connecting the rotor and the machine body, directly determines the stability and safety of equipment operation. With its outstanding advantages such as non-contact measurement and high precision, the eddy current displacement sensor has become the key technical equipment for bearing bush displacement monitoring, fortifying the "defense line" for critical equipment such as steam turbines, hydro turbines, and generators.

The monitoring principle of the eddy current displacement sensor is based on the eddy current effect in electromagnetic induction. The sensor probe is equipped with a high-frequency oscillating coil, which generates an alternating magnetic field when energized. When the probe approaches the surface of a metal bearing, the magnetic field induces eddy currents within the bearing. Displacement changes in the bearing alter the gap between it and the probe, consequently affecting the intensity of the eddy currents. These changes are converted into a linear voltage signal through circuitry, enabling precise quantification of displacement parameters. This non-contact measurement mode fundamentally avoids the wear on the bearing surface caused by traditional contact measurements while eliminating mechanical interference from moving components.

The core requirement of journal bearing displacement monitoring lies in detecting minute radial and axial deformations, which is precisely what eddy current sensors excel at. In radial monitoring, the sensor can capture real-time radial runout caused by load variations and unbalanced forces with an accuracy of 0.1 micrometers, enabling early warnings for issues like rotor misalignment and bearing wear. For axial monitoring, it accurately tracks axial thrust movements, preventing potential collisions in the shaft system due to thrust bearing failure. A case study from a thermal power plant's turbine maintenance showed that after installing these sensors, the response time for abnormal bearing displacement warnings was reduced from 15 minutes to just 2 seconds, successfully averting three major shutdown incidents.

Compared to other monitoring technologies, the eddy current displacement sensor demonstrates unique advantages in bearing monitoring. Its measurement range can be adjusted as needed, flexibly adapting to different specifications of bearings from 0.1 millimeters to several hundred millimeters. Even under harsh working conditions such as high temperatures, oil contamination, and vibration, it maintains stable performance, making it suitable for complex industrial environments like power plants and metallurgy. Additionally, the sensor exhibits exceptional long-term stability, with a calibration cycle that can be extended up to 12 months, significantly reducing maintenance costs.

In practical applications, the installation and calibration of sensors are critical to ensuring monitoring effectiveness. The probe must remain parallel to the bearing surface, with the installation gap maintained within the optimal linear range, while avoiding interference sources such as scratches and oil stains on the bearing surface. By integrating with the data acquisition system, sensors enable real-time transmission of displacement data, trend analysis, and anomaly alerts, forming a closed-loop operation and maintenance system of "monitoring-analysis-warning.".

With the intelligent upgrading of industry, eddy current displacement sensors are deeply integrated with IoT and big data technologies, achieving a leap from single-point monitoring to comprehensive perception. In the critical field of bearing displacement monitoring, they serve not only as "precise intelligent eyes" for equipment operational status but also as the core driver in transforming rotating machinery maintenance from "reactive repair" to "predictive maintenance," providing robust safeguards for safe and efficient industrial production.