Nowadays the rolling stock is equipped with electric drive of high power. Frequency turning regulation, motor protection from overheating and limitation of starting currents are made with the help of semiconductor elements. For reliability improvement of starting and regulating facilities it is reasonable to use low component count. Running through regulating facilities current decrease simplifies electric circuit configuration. The authors propose to use thermal resistors as main elements. In the article the authors examine construct specifications of polycrystal temperature dependent semiconducting resistances of coaxial type and their advantages. There are some theoretical propositions which describe the work of thermal resistors and also some algorithms for synthesis of coaxial type starting devices. The authors made mathematical modeling for starting devices of different types based on thermal resistors. In the article there are some graphical dependences describing starting process.
Keywords: high power thermal resistors, thermal resistors of coaxial type, current density, specific generations of heat, criteria of similarity, starting device, starting current, synthesis of starting devices