Relationship between stator core buckling, core losses, vibration and local over-temperatures

Measurements on a hydrogenerator stator core during core test with higher-than-normal magnetic flux and extended test time provided the base for a study of interaction between buckling, local heat generation, hot spots, and vibration. The mechanism of buckling is analyzed. Curves were developed showing how the buckling influences the temperature at the bottom of the slot and between the stator coils. There is clear evidence that the core does not behave as a homogeneous structure. The upper and lower halves of the core may vibrate independently of each other, with different node numbers. The node number may be an odd number, contrary to the accepted theory. The magnitude and position of buckling does not seem to have any influence on the distribution of vibration nodes