Abstract: Devices for contactless data and energy transfer include a stationary part having at least one coil for data and energy transfer, and a moveable part having at least one coil for data and energy transfer and having at least one memory unit. A method for reducing power loss in the devices includes transferring a test data word from the stationary part to the moveable part at a maximum energy, in an initializing mode, storing the transferred test data word in the memory unit of the moveable part, subsequently reading a test data word out of the memory unit of the moveable part and comparing the transferred test data word and the read-out test data word in the stationary part, reducing an energy supply if the transferred test data word and the read-out test data word match, and raising the energy supply by a defined amount and ending the initializing mode, if the transferred test data word and the read-out test data word do not match.