Accelerated voltage endurance testing of micaceous insulation systems for large turbogenerators under combined stresses

The electrical life of micaceous insulation for high-voltage electrical machines was investigated by means of accelerated voltage endurance tests under carefully controlled operating conditions. The aging mechanism is assumed unchanged when the insulation is subjected to dielectric field strengths up to ten times normal and test frequencies up to 4000 Hz. A test program was developed whereby the useful electrical life of a particular test specimen can be determined as influenced by temperatures up to 130°C and mechanical stresses approaching the ultimate strength.