Noise measurement diagnostics for large electric machines

In the field of power engineering, much attention is paid to low machine failure rate and minimisation of shutdown periods that are always associated with major financial losses. That is why methods of non-destructive testing of the power generating equipment under operation are preferred to regular inspections under shutdown periods that often do not reveal any machine defects. This paper presents a diagnostic method for checking the mechanical condition of transformer frame and core and electric generator stator. The method is not intended to replace the conventional diagnostic measurements or tests, but to make possible early detection of places and the likely causes of future defects. It may be used in combination with other diagnostic methods to identify potential weaknesses in large electric machines and equipment where the condition, in particular compression force and its uniformity, of the magnetic core is of great importance.