Balancing of Flexible Rotors

Abstract

A study of balancing of flexible rotors with uniform cross sections supported by two bearings at both ends is performed by calculation, putting m as the number of critical speeds which are in the operating speed range. Using m+2 balancing planes, we can eliminate the static and dynamic unbalances at low speeds and the vibration components of the normal modes of the 1st, ……, mth order. When the rotors are simply supported, however, the vibration caused by some modal components of higher orders may appear in the high speed range. We can remove this vibration by employing m+4 balancing planes; we add the balancing operation to eliminate the two bearing forces at the highest speed. Regarding the rotors with spring supports and the rotors supported by springs and dampers, we can balance them by using balancing planes fewer than m+2 or m+4, when the supports are soft.