The impact of low amplitude 100 Hz vibrations on the winding insulation of rotating high voltage machines “

In order to improve insight into the impact of mechanical stress on the winding insulation of rotating machines, for the first time simultaneous electrical and mechanical stresses were applied at a frequency as high as 100 Hz. Improving tests described in literature, vibration frequency and bending stress were chosen closer to reality such as 100 Hz and 7 N/mm2, respectively. The goal was to find out what the insulation behavior would be like if the insulation was aged under such conditions. It is found that even at these low bending stresses time to breakdown is reduced significantly. The shortest values of time to breakdown have been found with insulations near room temperature. It is concluded that mechanical vibrations in rotating machines at machine start-up are especially harmful.