VW Shanghai: High-tech production with CPS from VAHLE

The CPS Contactless Power System is now in use in the VW automobile plant in Shanghai. The automotive maker from Wolfsburg is taking advantage of the virtually maintenance-free technology which VAHLE of Kamen, working jointly with VW, has developed up to market readiness.

In the old trading city of Shanghai, which since 1948 has developed into one of the leading industrial centres in China with some 13.5 million inhabitants today, the VW Group produces cars exclusively for sale on the constantly growing Chinese market. In the extension to the existing plant, opened by German Chancellor Gerhard Schröder who paid to visit to China specially for that purpose, the floor transport system (FTS) in the "Chassis Fitting" shop has been equipped with CPS technology, already working successfully in other plants of the company. Contactless Power systems for floor transport offers considerable advantages over the technologies previously used. While the conductor systems normally employed for automobile production operate reliably, they need frequent maintenance. Through the completely contact-free operation of the CPS system from VAHLE, maintenance is reduced to a minimum. This is a crucial factor, because it considerably increases the operating times of the transport systems. The floor transport system, produced by Expert Maschinenbau GMBH, is a circuit with a length of 160 metres, equipped with a lifting station and with 24 vehicles operated by 24 V DC.A 0,5 kW pick up is installed under each vehicle to collect and process the current, which is transmitted by induction.

The technology

The CPS system transmits the energy on the induction principle, similar to that used in a conventional transformer. But unlike a transformer, where the primary and secondary windings are located on a closed ferromagnetic core, in the CPS system the stationary primary winding is extended to form a long cable loop. The mobile secondary winding (pick-up coil) is placed on an open ferromagnetic core and coupled with the magnetic field of the primary winding. This allows free movement of the two windings relative to each other. Optimum, low-loss transmission is ensured by the primary inverter, which converts the 50 Hz alternating current from the mains into single-phase 20 kHz alternating current and feeds it into the primary cable. The advantage of CPS technology as compared to conventional systems were so convincing that the planners of the Volkswagen Group decided to make use of VAHLE technology for equipping their new production lines in China; also four overhead monorail systems and a skillet line have been fitted with individually insulated conductor rails (unipole conductors) from VAHLE.

Other automobile manufacturers throughout the world have also decided to operate the floor transport systems in their production plants using CPS in future. Experience with the systems already installed suggests that the potential applications for this technology are only just starting to be discovered. Developing CPS further and adapting it for new applications will be one of the exciting challenges at VAHLE for the future. All customers who install these systems can be sure that they are already using a technology of the future.