TCC is a TDS module for ELMAG-3D which does magnetic core heating calculation. It is aimed to define temperatures of steel surface contacting with oil, the place and the magnitude of the hottest spot of magnetic core at no-load mode. The module creates 3D model of magnetic core with application of no-load volume losses. Boundary conditions are the average factors of heat transfer applied to magnetic core the leg and yoke surfaces and determined the Similarity Theory criteria equations with Grashoh, Reinolds, Prandtl and Nusselt numbers usage. The user can change the model manually and edit formulas for heat transfer factor determining represented in the database.