| Abstract |
The two-phase cooling system is more and more frequently used in railway equipments. This system must be adapted to the recent evolution in semiconductor technology, with the appearance of the GTO (gate turn-off thyristor) which has had an influence on the structure of forced commutation circuits. ALSTHOM has developed a new cooling system (SMF 1), which comes in the form of an interchangeable panel. This panel performs the total function of a chopper or of one inverter arm, taking into account wiring requirements between the GTO and the auxiliary circuits. The essential elements managing this development are reliability, ease of maintenance and standardization. The system uses Freon R113, with the following advantages: no pump, a low volume and high thermal dissipation. The components are not submerged, and the evaporators are linked to a single condenser, which is designed for system average losses. Natural convection is possible. This system has been used in the underground systems in Lyon (MPL 85) and Paris (MI 84). |
