1. Electric Power Research Institute of Guangdong Power Grid Corporation, Guanzhou 510080,China; 2. National Engineering Research Center of Turbo Generator Vibration, Southeast University, Nanjing 210096,China
Abstract：The finite element model to calculate unbalance response for a 1000 MW ultra supercritical turbine with single bearing support was set up. Unbalance response during run up process was calculated and analyzed. Response difference between single-bearing support unit and double-bearing support unit was compared. It is pointed out that bearings at two sides of the rotor can be treated as the double supports of the rotor. Unbalance plane and unbalance mode can be analyzed from vibration of these bearings. Vibration coupling between rotors is large exists especially at rotor resonance zone. If operation speed is far away from critical speeds, the coupling effect is not distinct. Phase lag between the coupling unbalance and vibration at operation speed is usually larger than 120 degree though the 2nd critical speed is far less than the operation speed. High speed dynamic balance test was done for a 1000 MW unit in field. The calculated results were verified.
2014, Vol. 33 
