Common transit vibration analysis of the failure of the treatment and prevention
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Abstract: This paper reviews the common rotating machinery vibration were the causes of the harm, inspection, treatment and prevention, the use of equipment for the management of technical personnel for reference.
Key words: turn for the better; vibration fault; reason; analysis; processing; prevention
Key words: TB123 Document code: B
 
Vibration usually turn for the better There are four reasons: the imbalance, resonance, and not mechanical failure.
1. Rotor imbalance
It is the most common causes of vibration, such as non-performing manufacturing rotor, rotor blades on the accumulation of foreign bodies, such as non-performing rotor balance.
A greater imbalance in the vibration equipment is another reason for the lower base of the stiffness or resonance.
Key and keyway also lead to another reason for the imbalance vibration.
Heat shaft bending caused by rotor imbalance is another phenomenon. General thermal bending vibration caused by unbalanced load with a slight change changes. However, if the device with rotating basis resonance occurs, then there is a strong potential severe vibration. As a result, the key to prevention, one of the shaft material must meet the requirements; second, turning a solid base to be reliable.
2. Resonance
The system depends on the resonant frequency of its number of degrees of freedom; by the quality of the resonance frequency, stiffness and attenuation coefficient decision. Turn for the better support should stay away from any resonance frequency excitation frequency. The new device can be made to the consultation required for manufacturing the foundation stiffness in order to achieve this. For the same resonance frequency and speed of existing devices have two options - to minimize the vibration or resonance frequency changes. The latter can increase the stiffness of the system and to achieve quality. Resonance to deal with the problem, it is best to change the resonant frequency.
Resonance may be wrong or by the mechanical and electrical fault caused.
Under the speed of harmonic resonance frequency also cause failure. They may also be due to misalignment or mechanical and electrical failure induced. However, with the same frequency of the problem, caused by the resonance of these issues are not common.
3. Misalignment
It may be twice the speed and the speed caused by the axial and radial exciting force. But can not because there is no above-mentioned phenomenon of one or both of which concluded that there is no question. At the same time, consideration should be given to the thermal expansion of the unit, a coupling between the left to 1.5-3mm gap.
4. Mechanical failure
Poor quality of the coupling, bearings and lubrication is not bad, as well as strong support, are different frequency and amplitude of excitation.
(1) poor quality of the performance of the coupling of the main cast in the poor quality connection Luokong deflection, Burr, a rubber gasket damage quickly, so that the coupling from soft to hard to connect to connect, have a vibration, wear and tear.
(2) the replacement of the radial bearings are generally easy to replace. In order to avoid vibration replacement bearings, outer bearings should be to make contact with coloring inspection and, if necessary, to address bearing.
(3) is caused by fluctuations in the axial turn for the better, including coupling, bearing another into the cause of the vibration problem. General transfer of axial thrust by thrust bearing bound. However, in non-performing of the axial and axial rotor Moceng occur, it may have severe axial vibration.
(4) that the weak support of the four legs is not the same plane. Turn for the better fastening bolts used in this 4:00 pm, if not all bearings, the inevitable result of severe vibration. Therefore, the installation of turn for the better, should be first symmetrical appropriate moment tightened a few fastening points. Then every time a loose fasteners, and Micrometer measurement of the vertical deformation point. If the vertical deformation greater than .05 mm, this support should be added at the foot pads, equal to the thickness of its deformation. Repeat the above process until the release time of each point of the vertical deformation is less than 0.05mm up.
(5) turn for the better base and foundation of the problem may be excessive vibration of the direct cause. Bolt must therefore have sufficient strength, solid concrete foundation for non-empty, turning to run in the regular check whether the bolt loose, broken and in a timely manner and to rule out the possibility. At the same time, to check the transfer of the subsidiary connection is strong support equipment.
In addition, the gas pump as a result of corrosion caused by vibration is more common. There are between the stator and rotor of the radial rub can easily cause vibration, which is the frequency of vibration-induced vibration, so turn for the better when the assembly must pay attention to dynamic space. In addition, there are a large axial fan surge, a steam turbine bearing oil film oscillation. In short, a familiar turn for the better vibration common causes of failure, can also use various types of vibration instrument to deal with and prevent vibration.