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Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

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Vibration <strong>and</strong> Noise in <strong>Pumps</strong> 459<br />

Figure 18-22. Allowable residual unbalance for industrial machinery ASA St<strong>and</strong>ard<br />

2-1975 [34].<br />

However, with oil film bearings, the clearance between the shaft <strong>and</strong><br />

bearings <strong>and</strong> the damping of the oil r<strong>ed</strong>uces the vibrational force transmitt<strong>ed</strong><br />

to the case. For rotors with oil film bearings, shaft vibrations are a<br />

better indicator of unbalance conditions. The API-610 allowable vibrations<br />

for pumps with sleeve bearings (oil film) are bas<strong>ed</strong> on shaft vibration<br />

measur<strong>ed</strong> at rat<strong>ed</strong> spe<strong>ed</strong> <strong>and</strong> capacity. The API-610 specifies the allowable<br />

unfilter<strong>ed</strong> vibration shall not exce<strong>ed</strong> a velocity of 0.40 ips nor<br />

exce<strong>ed</strong> a displacement of 2.0 mils peak-peak including shaft runout.<br />

For critical installations, vibration monitoring equipment should include<br />

non-contacting proximity probes (vertical <strong>and</strong> horizontal) at each

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