Balancing fast-rotating parts of hand-held machine drive

The article considers the issues related to the balancing of fast rotating parts of the hand-held machine drive including a wave transmission with intermediate rolling elements, which is constructed on the basis of the single-phase collector motor with a useful power of 1 kW and a nominal rotation frequency of 15000 rpm. The forms of balancers and their location are chosen. The method of balancing is described. The scheme for determining of residual unbalance in two correction planes is presented. Measurement results are given in tables

Use of modal weight sets for residual modal unbalance assessment of high speed balance quality of flexible rotors

The paper proposes a rather simple method of residual modal unbalance assessment using modal weight sets. The method works well for evaluation of the first two modes and reasonably well for higher modes as long as there is enough separation between them and there are no overhang modes. Validation was performed based on factory residual vibration limits for at least 50 flexible rotors of different frame-sizes. A relatively good correlation of factory vibration limits and results obtained with weight sets was achieved. These results were in-line with limits set in ISO 1940, ISO 11342 and some OEMs. © M L'vov, E Uryev, 2012