Measure the new vibration and c phase angle. However, the lowest desired limit is 3 times better. That is, their angular orientation is 90 degrees apart, as shown in the Figure. Fig A 1X Fig B. This is actually typical for this rotor section after long periods of operation in corrosive environments. ISO: Mech. IS: Mech. IS: Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel.
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Broken blades On set of cavitation. Damaged or misaligned drives Presence of solid bodies Damaged bearings in pump fluids. Eccentricity Static or dynamic unbalance. Fretting corrosion Worn bearings. Mohamed Gaber El-Naggar.
Saptarshi Basu. Shameer Majeed. Ivo Perez. Afham Ahmad. Lakshmanan subas chandra bose. Munteanu mas. The measurements were made using a laser vibration meter, are very precise and can be controlled with a PC. The displacement of the membrane is smaller for the advancement than for the receding.
A copper line could be attached to the system, line which could suffer tensions or distortions, but could be displaced horizontally very precise. Introduction During the last years many high-precision numerical equipments for measuring the displacements have been developed [1] [2]. The laser vibration meter is a device which performs non-contact single-point or differential measurements, which visualize vibrations or microscopic cartography of a surface.
Laser vibration meters are used to measure precisely mechanical vibrations [3]. They are based on Doppler principle, measuring the laser ray dispersed back by a vibrating object, to determine the displacement and the speed of the vibration [4].
Measurement scheme with 4 virtual rooms The mathematical approach and the signal processing algorithms are taken from [5] [6], resulting the equations needed for the implementation of the measurement method.
Measurement method for small and very small displacements Experiments and measurements with a single loudspeaker have been carried on.
Computer for the automatic system control; 2. Power supply Agilent A; 3. Oscilloscope Tektronix TDS; 4. Laser vibration meter; 5. Ammeter; 6. Loudspeaker; 7. Sensor-head of the laser vibration meter. The power supply is connected together with the oscilloscope to the computer via the GPIB interface, thus the current and voltage could be set and the oscilloscope signal is visualized on the computer. The loudspeaker is connected to the power supply and the oscilloscope is connected to the signal output of the laser vibration meter.
The vibration meter is connected to the sensor-head of the vibration meter. This is positioned such as the laser ray come perpendicularly on the plane surface of the loudspeaker and to be reflected exactly to the sensor-head. In order to have a good reflection, the laser contact surface and the membrane with TiO2.
To visualize the functioning of the system, a value for the output current and voltage is set. In such manner we obtained a signal that shows the difference, in Volts, between the final position of the membrane after setting the current and its initial position.
The voltage will stay at 8 V and the current will be variable, according to the displacement we want to obtain. The bigger the current, the bigger the displacement will be. There are two Matlab programs, one to initialize, to set and to control the power supply, and the second one to read the values from the oscilloscope. We notice a barrier drop in the right-hand side of the graphic We eliminate this part and we use the data until second 8 from the time-axis.
The voltage difference D will be the difference between the Df and Di, where Df is the average of the perturbations from the second 0 to second 3, and Di is the average of the perturbations from the second 4 to second 8.
Thus, for a real output current of 0. The measurements are carried on until a current of approximately 0. Results of the measurements are presented in the following charts. Because the power supply has a minimum output current of 0. The purpose of this resistor is to lower the current from the loudspeaker and to obtain smaller displacements of the membrane. Conclusions A system with a laser vibration meter, capable to perform small and very small displacement measurements is presented.
These displacements are very precise and could be very well controlled by the computer.
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