7.8. Rotor high speed balancing acc

7.8. Rotor high speed balancing acceptance criteria In table 1, for rotor type A, the rotor vibration acceptance limits (TOL) for HSB are shown. The values in mm/sec rms are related to the vibrations of high speed balancing machine pedestals DH50, DH8, DH7, DH6 and DH4 of Schenk balancing plant. In table 2, for rotor type B, the rotor vibration acceptance limits (TOL) for HSB are shown. The values in mm/sec rms are related to the vibrations of high speed balancing machine pedestals DH50, DH8, DH7, DH6 and DH4 of Schenk balancing plant. For Type B rotors, in the event that the criteria reported in table 2 cannot be fully met, the readings of the proximity probes may be adopted, and the level of balancing is considered acceptable if : - support vibration is within the average of limits from table 1 and 2 (average between Type A and B). - the vibration readings at proximity probes, with locked supports, are within the limits reported in table 3. Such limits, as per API612 7th par. 9.7.6.3 are referred to peak-to-peak vibration amplitude, filtered on synchronous speed, with compensation of run-out. Note: The rotor shall be balanced as described in all the previous paragraphs, within the acceptance limits indicated in table 1 or table 2, depending on rotor type and the criteria presented in current paragraph. In table 1 or 2 the acceptance criteria depend on pedestal stiffness (locked/unlocked), on the bearing static load and on the rotor speed, according to API612, 7 th ed., paragraphs 9.7.6.1 and 9.7.6.2. The values for locked pedestals must be used only if the vibration amplitude exceeds 20 mm/s (see chapter 4).