Merit award

Winding-less Magnetometer to Measure Permeability and Core Losses

Magnetic measurements on a standard toroidal specimen, particularly relative permeability and core losses, are currently made using a winding magnetometer. This is done by winding primary and secondary coils on the sample. By applying an alternating current into the primary winding and measuring the induced voltage in the secondary winding, the material’s magnetic properties can then be determined. However, this method requires manual work, because windings must be directly applied onto the specimen. In this work, a winding-less magnetometer, which does not require windings to be directly applied onto the material, has been created to measure toroidal specimens. The primary coil was placed in the centre of the toroid and sensing coils were in the centre and sides of the ring to detect magnetic fields around the specimen. It was calibrated using standard winding setup. From the amplitude and phase of the voltage in the secondary coils at various frequencies, relative permeability and core losses were determined. Moreover it can distinguish losses due to hysteresis and losses due to eddy currents. Measurements of toroids of iron and nickel sheets and 3D-printed cobalt-iron toroid showed that 3D-printed material has considerably lower permeability and higher core losses due to higher eddy currents. The winding-less magnetometer is helpful for fast and accurate measurements of magnetic properties.