DIN ISO 21940-13:2012-08

Many rotors are balanced in specially designed balancing facilities prior to installation into their bearings on site. However, if remedial work is carried out locally or a balancing machine is not available, it is common to balance the rotor in situ, that is with own support and with bearing support. Unlike balancing in a specially designed balancing machine, in-situ balancing has the advantage that the rotor is installed in its working environment. Therefore, there is no compromise with regard to the dynamic properties of its bearings and support structure, nor from the influence of other elements in the complete rotor train. This standard specifies procedures to be adopted when balancing medium and large rotors installed in their own bearings on site. It addresses the conditions under which it is appropriate to undertake in-situ balancing, the instrumentation required, the safety implications and the requirements for reporting and maintaining records. The procedures covered in this standard are suitable for medium and large machines. However, many of the principles are equally applicable to machines of a smaller size, where it is necessary to maintain good records of the vibration behaviour and the correction mass configurations. It does not provide guidance on the methods used to calculate the correction masses from measured vibration data. This standard can be used as a basis for a contract to undertake in-situ balancing. The underlying International Standard ISO 21940-13 "Mechanical vibration - Rotor balancing - Part 13: Criteria and safeguards for the in-situ balancing of medium and large rotors" has been prepared by Technical Committee ISO/TC 108/SC 2 "Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures", the secretariat of which is held by DIN. The German collaboration was effected by Committee NA 001-03-06-01 (NALS/VDI C 6.1) "Auswuchten und Auswuchtmaschinen" ("Balancing and balancing machines") of the Acoustics, Noise Control and Vibration Engineering Standards Committee (NALS) at DIN and VDI. This standard differs from DIN ISO 20806:2010-03 as follows: a) the number of the standard has been changed; b) the standard has been slightly editorially revised and aligned with the current terminology.