Vibration analysis and improvement of stator core in Three Gorges hydro-generator

The vibration of stator core in large-scale hydro-generator is a critical problem that should be considered in motor’s design procedure and operation. Electromagnetic vibration of stator core can be classified into two categories: one is low-frequency vibration at rotor frequency and multiples of rotor frequency, which results from that the rotor is slightly out of round, the other is electromagnetic vibration at the frequency of 100 Hz, which is caused by the interaction between the reversal sub-harmonic component of MMF and the fundamental flux density. In this paper, the 100Hz electromagnetic vibration for the number 18 hydro-generator of Three Gorges Dam is analyzed and the vibration source is determined. The improved winding’s connection is proposed in terms of vibration source and applied to the number 16 hydro-generator. The calculated results can be proved that the proposed winding’s arrangement is an effective means to reduce 100Hz vibration.