Performance of low frequency magnetic field meters to sinusoidal and beat-phenomenon magnetic fields

Performance of low frequency magnetometers to non-sinusoidal magnetic fields

“…The measurements have been performed using the same octagonal Helmholtz coil having a coil constant correction curve in a frequency range from 0 to 10 kHz used in [1]. The octagonal Helmholtz coil with centrally directed windings has one axis, the ratio of the inscribed circle of the most inner turn is R in = 503 mm, and the 1% -homogeneity region, virtually spherical, has a size of 41.6 dm 3 .…”

“…[1] (both type of meters have frequency analysis tools, but type b meters have a frequency range below 10 kHz and type d meters have a frequency range above 10 kHz). Table 1 shows the list of the tested magnetometers with the following information: magnetometer number for identification purposes, type of meter according the above classification, sensor type, number of axes, core type, cross-section area, and frequency range.…”

“…A previous paper [1] showed the importance and pertinence of performing evaluations of commercially available magnetometers. During the research work described in [1], 41 magnetometers were tested using sinusoidal fields, and it was concluded that, in the analysis of sinusoidal signals up to 10 kHz, there exist meters that can measure such fields with small errors, i.e., the meters fulfilled the IEC standard [2] which states that the measurement uncertainty of the instrumentation should be less than ±10% in the frequency range from 15 Hz to 9 kHz.…”

“…During the research work described in [1], 41 magnetometers were tested using sinusoidal fields, and it was concluded that, in the analysis of sinusoidal signals up to 10 kHz, there exist meters that can measure such fields with small errors, i.e., the meters fulfilled the IEC standard [2] which states that the measurement uncertainty of the instrumentation should be less than ±10% in the frequency range from 15 Hz to 9 kHz. However, in the test using fields with beat phenomena, larger errors were found in several meters in the rms waveform measurement, reaching error values of up to 35%.…”

“…It was also stated that the increased error in the rms measurement of beat waveforms (a non-sinusoidal waveform type) demanded a deeper research on the accuracy of magnetometers when non-sinusoidal waveforms are measured. Moreover, five previous studies on magnetometers [3][4][5][6][7] have been analyzed in [1], concluding that although some commercially available magnetic field meters currently have frequency analysis tools for magnetic fields up to frequencies of some kHz, there is still a lack of knowledge about the measurement accuracy for the complex case of having several harmonic components like those that usually appear in electrical distribution networks. Thus, this paper shows the results of the second part of the study.…”