vibration measurement methods
Posted on December 10, 2020

Among these, vibration measurements are the most widely used. An impulse vibration measurement involves striking the object, often with a “calibrated hammer” that measures impact force, and then measuring the resulting vibration of the object. Users can then give the info to whoever needs it for analysis or presentation. View our selection of Vibration Measurement Data Acquisition Systems, Vibration/damage diagnostics in transmissions, bearings and shafts, Shaft/bearing vibration in hydro & gas turbines/generators, FFT (Fourier Fast Transform) Spectrum Analysis, Diagnostic Considerations: Operator Experience, Machine Datasheets, Trending over Time, Comparison to Standards. The purpose of the standard test is to provide a repeatable and reproducible method of estimating vibration emission. Probes with threaded bodies tightened into a rigid mount should provide the rigidity needed to minimize vibration effects. Vibration is measured as an acceleration, velocity, or displacement. In addition, many vibration instruments can take generic signal inputs, including voltage, current, frequency, and serial inputs. Vibration Isolators There are different clamp mounting methods for cylindrical style probes; some are better than others. The disadvantage of measuring speed from an analog signal is in attempting to configure the correct sample rate. The most common measurements users take in vibration monitoring applications are: In another common application, Shock measurement, users record data and later view it searching for a single event. In other applications, a simple “total vibration” number is required. Relative measurement. The accelerometer produces an electrical signal. Vibration measurements are thus usually taken at the bearings of machines, with accelerometers mounted at or near the bearings. Vibrations at higher frequencies have greater accelerations than those at lower frequencies. In a typical application, users are looking for characteristic signals of machine failures, for example in hydroturbines, engines, etc. Viewing vibration in the frequency domain reveals the magnitude of vibration at different frequencies. Broadband vibration measurement is the most widely used and cost-efficient method for the diagnosis of overall machine condition. process the data in real-time. Vibration analysis involves using a vibration sensitive transducer and instrumentation to measure and record the vibration characteristic of a rotating machine. It directly measures what happens to the object of interest under real operating conditions. This is an absolute method that consists of measuring the displacement with a laser inter- ferometer and a precise frequency meter for accurate frequency measurements. An accelerometer placed at any one point on the geared motor will measure a COMPLEX VIBRATION waveform as shown in the time drawing on the left side. Basic pipework vibration measurement provides a simple method of identifying areas of concern based solely upon measured values of pipework vibration. Using a Fluke vibration meter with the Fluke Connect ® app, you can share inspection results and authorize next steps from the field, organize your … Reference frame for vibration measurement. Other Ground Vibration Measurement Instruments. For this reason, the distance between the sensing face of the probe and the mounting system must be at least 1.5 times the probe diameter. Therefore, condition monitoring is best performed using a vibration recording device. Acceleration and displacement are the most common methods of vibration measurement. This is … The measurements can be performed at room temperature or at elevated temperatures (up to 1700 °C) under different atmospheres. The differentiation process will limit low frequency signals and emphasize higher frequency signals. This requires collecting vibration data and viewing the peak-to-peak values. Configure a characteristic channel for, Large turbine = 10 Hz (revolutions) per second, Standard electric motor: about 1700 RPM = 30Hz per second. ... all methods of use of the equipment, or of current models of construction equipment. To achieve this, many standard tests are based on artificial operations. Each has advantages and disadvantages and each vibration measurement unit can be converted to the others although with potentially adverse consequences from the conversion. Changing “total vibration” can be measured with Tracking TIR option of the MM190 Module. blade passing frequency), the frequencies of concern. While noise and vibration can be readily measured, harshness is a subjective quality, and is measured either via "jury" evaluations, or with analytical tools that can provide results reflecting human subjective impressions. As a high-end example, modern systems are capable of sampling speeds of 1,000 samples/second and of computing 1,024-pt FFT, while monitoring vibration on 4 channels. The objective is to extract these different harmonic vibrations from the combined wave. Option 2: Take the analog signal of the eddy probe and process the signal using the vibration data logger. Common ways to measure torsional vibration angular velocity oscillations are by means of toothed wheels or gears and magnetic pickups. Vibrations were measured on the upper lip by vibrometer and on the ala of nose by accelerometer. If this is unavoidable, special factory calibrations are possible to minimize interference. Production Label Sensors | Packaging System Sensors, Vibration Measurement; Vibration Sensors; Measuring Vibration Precisely, The object’s own natural frequencies and stiffness, The amplitude and frequencies of any external energy source(s) inducing the vibration. Dynamic strain of 400 nε (peak-to-peak, corresponding to phase shift of 17 rad) was reproduced with high quality by proposed method. In order to monitor vibration and decide on a measurement system, you first need to identify the key parameters of interest in your specific application. Environmental Considerations for Capacitive Sensors. Our specialised facilities allow us to quickly and easily run a variety of tests to fully analyse the performance of the motor under a variety of conditions. Sm = Mean Value Introduction. Additionally, in many instances, if you hear a bearing rumbling, this is an indication that it won’t last much longer—sometimes just a matter of days or even hours. This function facilitates experimentation with the object’s environment to determine what may reduce total vibration without the necessity of manual resets of the peak values. Meters and modules are ideal for simple applications such as monitoring a factory motor by recording machine vibrations and reducing them to a single analog output. In this test, we’ve used an MMA7361 triple-axis accelerometer from Freescale, mounted on a PCB with several external components to simplify use. A statistics calculating method is present to suppress the uncertainty in phase-measuring. Most monitoring systems allow the user the ability to select the bandwidth of the measurement frequency range. To minimize the effects of vibration on the sensors themselves, they must be rigidly mounted. Vibration tests for the last stage blades of a steam turbine were carried out in a high-speed dynamic CAS DataLoggers is a distributor of data loggers, data acquisition equipment, temperature monitoring systems, and paperless recorders. Capacitive displacement sensors have a measurement “spot size” about 130% of the diameter of the sensing area of the probe. 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