BENTLY 3500/05-01-01-00-00 3500 System Rack

BENTLY 3500/05-01-01-00-00 3500 System Rack

Introduction to Bently 3300 System
1.1 Working principle
The instrument measurement adopts the principle of approaching eddy current. The probe is composed of a coil with high-frequency signals. When the relative position between the metal surface of the measured shaft and the probe changes, the size of the eddy current formed changes, causing a change in the energy loss of the high-frequency signal inside the probe. This changed signal is converted into a voltage signal corresponding to the voltage measured by the probe’s gap through a preamplifier. This signal enters the monitor in the component box and is displayed as a reading after internal conversion by the monitor.
1.2 Composition of Bentley 3300 System Circuit
The system consists of a 3300 series instrument component box, corresponding preamplifiers, and sensors (probes) with cables. Each parameter is measured by a dedicated probe preamplifier and a monitor together.
2 Sensor calibration
The calibration instruments mainly include Bentley’s TK3-2E calibrator, a 4-bit and a half digital voltmeter, a 24V DC stabilized power supply, and a function generator.
2.1 Sensor calibration
1. Connect the probe and extension cable, with the other end of the extension cable connected to the preamplifier. Connect the power terminal (-24VDC) and common terminal (com) of the preamplifier to the -24VDC power supply, and connect the common terminal and output terminal to the digital voltmeter.
2. Fix the probe onto the probe holder with a suitable probe clamp, so that the top of the probe comes into contact with the calibration target.
3. Send -24VDC to the power and common terminals of the proximitor, then adjust the screw micrometer on the TK3-2E calibrator to align the indicated value with 0mm, then increase the indicated value of the micrometer to 0.25mm, and record the voltage value of the digital voltmeter (this value is the output voltage of the proximitor). Increase the gap by 0.25mm each time until the displayed value is 2.5mm, and record the output voltage value for each time (with no less than 10 verification points).
Based on the recorded data, draw the gap voltage curve of the calibrated probe sensor system in the form of the calibration curve of the axial displacement sensor, which reflects the characteristics of the sensor.
Based on the drawn gap voltage curve, determine the linear range of the sensor system, which should not be less than 2mm. The sensitivity of the sensor system should be calculated to be 7.874V/mm, and the nonlinear deviation within the linear range should not exceed 20um. The sensitivity is determined by dividing the voltage increment by the gap increment. The linear center of the sensor is the static set point of the axial displacement sensor.
The calibration method for vibration sensors is the same as data recording for coaxial displacement sensors. The gap voltage curve should also be plotted to calculate the sensitivity of the sensor system. Within a linear range of 2mm, the error of the sensor system should not exceed ± 5%. The linear center of the sensor serves as the installation reference point for the shaft vibration sensor.

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