The invention relates to an energy transmission device having a primary coil for transmitting to a detachable secondary coil electromagnetic energy by induction with the electromagnetic energy being characterized by an energy transmission frequency and sensing component for detecting at least one characteristic variable of a detachable secondary end including the secondary coil. The sensing component is adapted to detect information on the presence of a detachable secondary end in an especially reliable manner. For this purpose, the sensing component couples a measuring voltage having a measuring frequency that is different from the energy transmission frequency into the secondary coil.