Adapted Coil Sensors for Measuring the External Magnetic Field of Electrical Machines

This paper proposes a criterion in the choice of coil sensors which can be used in the diagnosis of electrical machines. These sensors allow us to measure external magnetic field of the machine. Their interest is due to their robustness, reliability and longevity. The principle of the coil sensors is to measure the magnetic flux located around the electrical machine in order to be analyzed to detect faults. The performance of the measured signal for a constant coil area depends on the number of turns and the wire diameter. Their influence is analyzed in the paper. The developed diagnosis method is based on the analysis of the radial magnetic field present around the machine comparing to the changes of two signals obtained from a pair of sensors. So, the sensibility of the sensor in the coil number is also analyzed in the paper.