The vibration problem resulted from misalignment of shaft system for targe-capacity turbo-generator sets is comparatively prominent

affecting safe operation of the units.Taking some type 600 MW units as examples

the characters of vibration trouble resulted from misalignment of three kinds

namely misalignment of generator-collector ring coupling

elevation deviation of bearing brackets between low-pressure cylinder and generator

and uncoaxiality between rotor and cylinder

for one type 600 MW turbo-generator sets have been analysed

and combining with practical examples

including unit no.2 in one power plant

unit no.1 in another power plant

and unit no.2 in other power plant

countermeasures adopted in operation and repair being given.