Combined with actual examples concerning vibration falt diagnosis and disposal for four turbo-generator sets

the causes leading to occurrence of shaft voltage(current) as well as its harm and influence upon shaft vibration have been summarized and analysed.It is believed that the main causes resulting in occurrence of shaft voltage on the turbo-generator set are bad insulation and bad contact of carbon brushes.The influence of shaft voltage is mainly resulting in deterioration of shaft or bearing vibration characteristics

and resulting in appearence of false signals

causing actuation of the vibration protection.