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Oil whirl

Fault to be detected Unbalance Misalignment Bent shaft Oil whirl Eccentricity Wear Faults In gears Faults In rolling element bearings... [Pg.914]

Same symptoms as bearing oil whirl except a decrease m lube oil temperature will often eliminate or reduce vibration severity. Seal ring oil whirl Oil ring seal acting as lightly loaded bearing... [Pg.423]

Same symptoms as bearing oil whirl, however, vibration frequency is constant even though speed IS changed. Resonant whirl Same as oil whirl except triggered by resonant component such as rotor, casing, piping, etc. [Pg.423]

The most obvious way to prevent oil whirl is to restrict the maximum rotor speed to less than twice its critical. Sometimes oil whip can be reduced or eliminated by changing the viscosity of the oil or by controlling the oil... [Pg.208]

Figure 5-23a. Oil whirl. (Ehrich, F.F., Identification and Avoidance of Instabilities and Self-Excited Vibrations in Rotating Machinery, Adopted from ASME Paper 72-DE-21, General Electric Co., Aircraft Engine Group, Group Engineering Division, May 11, 1972.)... Figure 5-23a. Oil whirl. (Ehrich, F.F., Identification and Avoidance of Instabilities and Self-Excited Vibrations in Rotating Machinery, Adopted from ASME Paper 72-DE-21, General Electric Co., Aircraft Engine Group, Group Engineering Division, May 11, 1972.)...
The frequencies of a spectrum can be divided into two parts subharmonic and harmonic (i.e., frequencies below and above the running speed). The subharmonic part of the spectrum may contain oil whirl in the journal bearings. Oil whirl is identifiable at about one-half the running speed (as are several components) due to structural resonances of the machine with the rest of the system in which it is operating and hydrodynamic instabilities in its journal bearings. Almost all subharmonic components are independent of the running speed. [Pg.570]

Bearing-support excitation Loose assembly of bearing liner, bearing case, or casing and support Oil whirl Resonant whirl Clearance induced vibration... [Pg.572]

When oil-film instability or oil whirl occurs, frequency components at fractions (i.e.,, etc.) of the... [Pg.745]

The primary vibration frequency components associated with fluid-film bearings problems are in fact displays of turbulent or non-uniform oil film. Such instability problems are classified as either oil whirl or oil whip depending on the severity of the instability. [Pg.1023]

Oil whirl In an abnormal mode of operation, the rotating shaft may not hold the centerline of the sleeve bearing. When this happens, an instability called oil whirl occurs. Oil whirl is an imbalance in the hydraulic forces within a sleeve bearing. Under normal operation, the hydraulic forces such as velocity and pressure are balanced. If the rotating shaft is offset from the true centerline of the bearing, instability occurs. [Pg.1024]

As Figure 60.28 illustrates, a restriction is created by the offset. This restriction creates a high pressure and another force vector in the direction of rotation. Oil whirl accelerates the wear and failure of the bearing and bearing support structure. [Pg.1024]

Oil whip The most severe damage results if the oil whirl is allowed to degrade into oil whip. Oil whip occurs when the clearance between the rotating shaft and sleeve bearing is allowed to close to a point approaching actual metal-to-metal contact. When the clearance between the shaft and... [Pg.1024]

Oil Whirl A vibrational instability of the lubricating fluid in high-speed journal bearings. [Pg.1865]

These curves relate to the response of a simple (Jeffcott) rotor with centre mass of 33 tonnes unbalanced by 0.33 k,g m. The rotors are similar in mass and stiffness to certain practical generator/turbine rotors and are designated as "flexible" and "stiff" respectively. This refers to their natural frequencies on rigid supports of 15 Hz and 30 Hz. It is possible to conceive of a very much stlffer rotor but this would not pose a stability problem from the point of view of classical oil whirl and is therefore irrelevant in the present context. Table 1 summarises the relative sensitivity of the various rotor bearing combinations. [Pg.351]


See other pages where Oil whirl is mentioned: [Pg.2506]    [Pg.423]    [Pg.157]    [Pg.157]    [Pg.208]    [Pg.209]    [Pg.483]    [Pg.668]    [Pg.682]    [Pg.688]    [Pg.740]    [Pg.773]    [Pg.332]    [Pg.1024]    [Pg.2261]    [Pg.2510]    [Pg.157]    [Pg.347]    [Pg.353]    [Pg.119]    [Pg.119]   
See also in sourсe #XX -- [ Pg.488 , Pg.570 ]

See also in sourсe #XX -- [ Pg.1865 ]

See also in sourсe #XX -- [ Pg.118 ]




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