Optimization of the Power Converter Cooling System within the Scope of the BLS RABe 525 (NINA) Retrofit
In 2015, BLS AG launched a three-year retrofit project for its 36 NINA multiple units (low-floor commuter trains). These include the optimization of the cooling system for the rooftop power converters in compliance with new requirements. Helbling analyzed the factors that had previously limited cooling capacity and used these insights to devise improvements.The power converter cooling system on the roof of the NINA multiple units had reached its limit. The limiting factor, however, was unknown. Helbling’s task was therefore to find a way to efficiently analyze and optimize the cooling system. In its capacity as a center of excellence for rail vehicles, Helbling was able to draw on many years of experience, particularly in the area of modernization and retrofit projects.
Key data and technical details
- Power converters convert the 15 kV 16 2/3 Hz overhead line voltage into a variable three-phase alternating current for the traction motors
- The power converters are air-cooled. Cooling air is drawn in by a radial fan near the roof and blown through the power converters at the ambient temperature
- The cooling system for the power converters must not limit the power supplied to the traction motors