Degradacja izolacji uzwojeń maszyn elektrycznych pod wpływem czasu ich eksploatacji

Results of dc voltage diagnostic tests of electric machines' insulation (Fig.1) enable the evaluation of insulation's of degradation in accordance with established marking system. The paper presents marking system set from 5 to 1 - see Table 1. The relationship between marking system and characterictics/parameters of insulation system has been shown, basing on results of diagnostic tests of armature windings' insulation of dc generator rated at 4150 kW; 730 V; 500 rpm (Figs.2-6). Table 2 gives the marks for technical assessment of insulation of 20 machines tested in 2000 and 2005. If the marks for 2005 are higher than for 2000, then it means that the machines have been rewound.