I. Introduction
Along with advancing power density and optimization the temperature distribution in an electro-hydraulical system gains importance. However it is mainly not the overall thermal behavior of a system that limits the performance, but the temperature at specific points or in specific areas. These areas contain components or materials with a defined maximum operating temperature which limits the safe operational area of the system. In the demand to increase the operational area it is crucial to understand not only the thermal distribution but also the interconnections of the involved subsystems. The main focus rests here on the calculation of the temperature distribution in the electrical, mechanical or hydraulic sub-systems due to internal heat losses. Since the beginning of the developement of electrical machines it is recognized that an efficient cooling of a system/machine is absolutely necessary to maintain its life cycle [1].