DIN EN 60034-18-34:2012-12

This part of DIN EN 60034-18 (VDE 0530-18) deals with the evaluation of insulation systems for form-wound windings under thermal cycling operation. This kind of endurance is of special importance for long rotating machines, especially indirectly cooled, and machines that are exposed to a very large number of considerable load changes during normal operation. The main ageing factor expected in this test procedure is a mechanical stress due to the thermal expansion difference between the conductor and the insulation, which is defined as a thermomechanical stress. In this test, a transient temperature gradient from the conductor to the outer surface of the bar or coil is generated with similar time constant as those found in real generators. This thermal cycle is repeated to induce fatigue in the insulation system. The responsible committee is K 311 "Drehende elektrische Maschinen" ("Rotating electrical machines") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.