Ageing of rotating machines insulation-mechanisms, measurement techniques

The long-term ageing of insulator models until breakdown was investigated with repetitive diagnostic measurements. The physical mechanisms in models with isolated defects were examined, and improved diagnostic tools were developed on the basis of the ageing experiments. Experimental results on the properties of a mica paper, glass fiber, and epoxy resin composite are presented. The authors discuss the effect of temperature on ageing and especially on defect induction by thermomechanical forces.<<ETX>>