Based on large amounts of field dynamic balance test data

the dynamic balance methods of asymmetric high-pressure rotor

unsupported medium pressure rotor and single supported low-pressure rotor used in the supercritical or ultra supercritical turbine produced by ALSTOM technology are studied. The results show that

there is a serious non orthogonal problem in the vibration mode of high pressure rotor

and the interference coefficient of vibration mode must be considered in the dynamic balance calculation. The first-order unbalance condition of the intermediate pressure rotor can be identified according to the vibration peak value and phase relationship at the No.1 and No.2 bearings in critical speed region. At a constant speed of 3 000 r/min

the firstorder or second-order unbalance condition of the intermediate pressure rotor can be inferred from the vibration amplitude and phase relationship at the No.2 and No.3 bearings. The unsupported side of the low pressure rotor can identify and decompose the unbalanced vibration mode by using the vibration information of adjacent bearings.