Contactless high speed signal transmission integrated in a compact rotatable power transformer

In many technical units containing rotatable parts it is necessary to transmit energy and signals through the joints. Systems for rotatable applications use slip rings or movable cables, which limit lifetime and flexibility. An inductively coupled energy transmission system is able to transmit several kilowatts through a rotatable joint without any mechanical stress or aging using a rotatable pot core transformer. The authors describe a new contactless signal transmission system inside this transformer. The system offers three independent analog signal transmission channels with a wide bandwidth. These are able to transmit digital information with data rates up to several MBit/sec. The bit-error-rate is extremely low even without using any error correction. This system may be used for any application demanding high reliability, such as robots, satellites or rotating measurement systems