Through calculating natural frequency of the base-plate and the core ellipse for 60 MW turbo-generator set without adopting vibration isolating base-plate

as well as the mode test for determining dynamic characteristics of the stator

it has been shown that the tested value of the natural frequency for core is very close to that for base-plate

the calculated value of natural frequency for core ellipse tallies well with its tested value

but the calculated natural frequency for base-plate ellipse has bigger difference with its tested value.For stator with similar structure

the core and base-plate have to be considered as an entity with rigid connection.giving priority to the core

and taking concurrently account of base-plate's influence.