DIN ISO 7919-2:2010-06

The standards of the DIN ISO 7919 series contain provisions for the evaluation of shaft vibration, the standards of the DIN ISO 10816 series contain provisions for the evaluation of housing vibration, when measured in situ in the radial direction, that is transversely to the shaft axis, at or next to the main bearings or in the axial direction on thrust bearings. Two criteria are provided for this purpose. One criterion considers the magnitude of the measured vibration; the second one considers changes in the magnitude of the vibration. In addition, different criteria are provided for transient operating conditions, such as run-up and coast-down. The evaluation procedures presented in these standards are based on broad-band measurements of - vibration under normal steady-state operating conditions; - vibration under other (non-steady-state) conditions, that is under transient operating conditions, including run-up or coast-down, initial loading and load changes; - changes in vibration which can occur during normal steady-state operation. The International Standards ISO 7919-2, ISO 7919-4, ISO 10816-1/Amendment 1, ISO 10816-2 and ISO 10816-4, which form the basis of this standard, have been prepared by Technical Committee ISO/TC 108 "Mechanical vibration, shock and condition monitoring", Subcommittee SC 2 "Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures", the secretariat of which is held by NALS. German collaboration has been performed through Working Committee NA 001-03-06-02 (NALS/VDI C 6.2) "Messung und Beurteilung von Maschinenschwingungen" ("Measurement and evaluation of machine vibration") of the Acoustics, Noise Control and Vibration Engineering Standards Committee (NALS). DIN ISO 7919-2 is applicable to land-based steam turbines and generators with a power output in excess of 50 MW and a nominal operating speed of 1 500 min ^-1, 1 800 min ^-1, 3 000 min ^-1 or 3 600 min ^-1. It is also applicable to steam turbines and/or generators which are directly coupled to a gas turbine (such as for combined-cycle applications); in such cases, the criteria of this part of ISO 7919 apply only to the steam turbine and the generator (including synchronizing clutches). Compared with DIN ISO 7919-2:2002-02, the following significant modifications have been made: - emphasis on the fact that acceptance criteria should always be agreed upon between the supplier and the purchaser prior to the installation of the steam turbine and the generator; - recommendation for setting the ALARM value for steady-state operation of new machines at the zone boundary B/C when no established baseline value is available.