Inductive monitoring device and method for monitoring the distance between a first and a second coil

摘要

The inductive coil monitoring system (11) has two terminals (29,31) connected to a direct current source. One of the coils is connected to an energy measurement circuit (25) producing an output current (27). An oscillator (33) is connected to a first coil (16) with an air core. There is an air gap (14) between the first and second (19) coil. A high-frequency alternating electromagnetic field, (approximately 3 MHz) is used to induce a current flowing through the second coil and an ohmic load (21) which may form an actuating device (15). The load on the first coil is measured.