Rotational Speed Measurement Using Induction Coil Sensor Inserted in the Magnetic Field of the Rotational Permanent Magnet

In this paper the application of induction coil sensor, inserted into a mechanical rotational magnetic field of the rotational permanent magnet for the rotational speed measurements has been proposed and described. The sensor is simple, low-cost, and applicable for machine shafts speed measurements (spatially available and unavailable). On the shaft, whose rotational speed is measured, the rotational permanent magnet is fixed. From measured frequency value of induced voltage in the coil sensor the rotational speed value is given using PC with adequate software, interface for the analogue signal conditioning and AD converter. The rotational speed dependence on the induction coil sensor distance from the rotational permanent magnet has been given. The induced voltage dependence on the coil distance from the magnet has been obtained as well. The maximum distance for precise measurements of rotational speed has been determined from those relations.