China is home to the largest and most extensively used network of high-speed trains in the world. Based in Beijing, the Chinese Academy of Railway Sciences (CARS) is the leading research and development institute, supporting this important industry with its specialized subsidiary, the Beijing Zongheng Electro-Mechanical Technology Development Co. Electrical Connectors helped to develop a traction converter for the latest generation of Chinese high-speed trains, while building up a partnership.
China’s network of high-speed railways covers a total of over 22,000 km of tracks. Just imagine: if you could put these rails in a straight line, they would take you halfway around the globe – and even a little further. Every day, thousands of Chinese are using high-speed trains, running at 250 to 350 km/h. The possibility of fast travel and commuting has profoundly transformed the country’s economy and society.
When China launched its first high-speed trains, they were imported or built under technology transfer agreements with foreign train-makers. After this initial technological support, Chinese engineers have re-designed train components and started building indigenous trains. Thanks to generous funding from the government, a dynamic local industry has developed over the past 15 years.
An important player in this market is the China Academy of Railway Sciences (CARS). Based in Beijing, CARS offers scientific and technological education as well as strategic consultation and certification services for the Chinese railway industry. A focal theme is research and the testing of new materials, products and technology.
In 2010, CARS updated an existing traction converter for use in the latest generation of Chinese high-speed trains. The connector fixed on the water-cooled board contains two poles and connects the IGBT module (insulated gate bipolar transistor) to the bus bars in the converter cabinet. High power transmission connectors were needed, fulfilling demanding requirements of the client for a safe and reliable solution. The higher the traveling speed of the trains, the greater the physical forces, therefore, the vibration resistance and stability are also critical. During maintenance, the module must be disconnected and replaced very rapidly to minimize costly downtime.
“I remembered having met Stäubli Electrical Connectors at an event in Beijing the year before.” explains Jianhua Cheng, Senior Engineer at CARS. “I was impressed with their MULTILAM technology, and thought they could help us find a solution.” So talks started between the two companies and a joint development project was initiated.
Step-by-step, trust was built up through joint workshops, technical seminars and a lot of internal testing.
In close cooperation with CARS, Stäubli developed a customized GSR2.5 bipolar fork connector, which realizes the connection between busbar and laminate busbar. The use of high-performance insulation material makes sure the product can meet the tough industry requirements of mechanical stability and long-term aging. “What finally convinced me was a third-party test, where Stäubli’s solution showed a highly stable performance over 300’000 km of high speed”, adds Jianhua Cheng. He knows about the benefits for his customers: “The solution is simple and easy to handle while ensuring safe and reliable operation of the train services. And our customers really appreciate the increase in productivity due to the fast connection and disconnection in maintenance.”
Bipolar fork connector (GSR2.5)
Application: connection between busbar and laminated busbar in IGBT
Stäubli fork connectors are built into traction converters
Joint development with the customer
GSR 2.5 fork connector in IGBT module of traction converter