IS 14817-3 (2004): Mechanical Vibration – Evaluation of Machine Vibration by Measurements on Non-Rotating Parts, part 3 Classification and evalutaion

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Machine classification
Classification according to machine type, rated power or shaft height
Rated Power (p KW) Shaft Height (h mm)
Group 1 >300Kw >315mm
Group 2 15<p<300 160 < H <315 .
Group 3 Pumps with multivane impeller and with separate driver power above 15Kw   NA
Group 4 Pumps with multivane impeller and with integrated driver power above 15KW NA
Classification according to support flexibility
  1. RIgid support
  2. Flexible support

determined by the relationship between the machine and foundation flexibilities.

the lowest natural frequency (combined machine and support system) in the direction of measurement is higher than its main excitation frequency (this is in most cases the rotational frequency) by at least 25 percent, then the support system may be considered rigid in that direction.

Evaluation
Criteria 1: Vibration magnitude
  1. concerned with defining limits for vibration magnitude consistent with acceptable dynamic loads on the bearings and acceptable vibration transmission
  2. The evaluation zones have been established from international experience.
Evaluation zones

   

Zone A Vibration of newly commissioned machines
Zone B normally considered acceptable for unrestricted long-term operation.
Zone C normally considered unsatisfactory for long-term continuous operation.
Zone D normally considered to be of sufficient severity to cause damage to the machine.
Evaluation zone limits

  Check the Table A1, A2,A3,A4 for the values

Axial vibration

Such measurements are primarily used during periodic vibration surveys or for diagnostic purposes. 

Certain faults are more easily detected in the axial direction. 

Specific axial vibration criteria are at the moment only given in the case of thrust bearings where axial vibration correlates with axial pulsations which could cause damage to the axial load-carrying surfaces.

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