To transmit electrical energy from a fixed type primary circuit to a secondary circuit capable of relative motion having the fixed type primary circuit and to retransmit measurement data generated in the operation of the secondary circuit to the primary circuit.

This primary circuit 1 is coupled with a secondary circuit 3 via one transformer 2 without contacting. This transformer 2 has one primary coil 4 of the primary circuit 1 wound around one fixed type core 5 and one secondary coil 6 of the secondary circuit 3 wound along a movable core 7 capable of relative movement with respect to the fixed type core 5, and the primary circuit 1 includes a voltage source 8 and an evaluation device 9 for induced measurement data and the secondary circuit 3 includes a sensing means 10, which generates measurement data and an evaluation device 11 which digitizes these measurement data. This output signal of the evaluation circuit 11 controls a short-circuit generator.