AS NZS 61786.1:2021 pdf free download – Measurement of DC magnetic,AC magneticand AC electric fields from 1 Hz to 100 kHzwith regard to exposure of human beings Part 1: Requirements for measuring instruments

AS NZS 61786.1:2021 pdf free download – Measurement of DC magnetic,AC magneticand AC electric fields from 1 Hz to 100 kHzwith regard to exposure of human beings Part 1: Requirements for measuring instruments.
This part of IEC 61786 provides guidance for measuring instruments used to measure the field strength of quasi-static magnetic and electric fields that have a frequency content in the range 1 Hz to 100 kHz and with DC magnetic fields to evaluate the exposure levels of the human body to these fields.
Sources of fields include devices that operate at power frequencies and produce power frequency and power frequency harmonic fields, as well as devices that produce fields within the frequency range of this document, including devices that produce static fields, and the earth’s static magnetic field. The magnitude ranges covered by this standard are 0,1 uT to 200 mT in AC (1 jiT to 10 T in DC) and 1 V/m to 50 kV/m for magnetic fields and electric fields, respectively.
When measurements outside this range are performed, most of the provisions of this standard will still apply, but special attention should be paid to specified uncertainty and calibration procedures.
Specifically, this standard
— defines terminology;
— identifies requirements on field meter specifications;
— indicates methods of calibration;
— defines requirements on instrumentation uncertainty;
— describes general characteristics of fields:
— describes operational principles of instrumentation.
NOTE Measurement methods that achieve defined goals pertaining to assessment ot human exposure are described in IEC 61786.2
Sources of uncertainty during calibration are also identified. In regard to electric field measurements, this standard considers only the measurement of the unperturbed electric field strength at a point in free space (I.e. the electric field prior to the introduction of the field meter and operator) or above conducting surfaces.
This horizontal standard is primarily intended for use by technical committees in the preparation of standards In accordance with the principles laid down in IEC Guide 108.
One of the responsibilities of a technical committee is, wherever applicable, to make use of horizontal standards in the preparation of its publications. The contents of this horizontal standard will not apply unless specifically referred to or included In the relevant publications.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies.
The voltage injection approach may not be applicable to probes with ferromagnetic cores because the permeability of the core may vary with the magnetic flux density and affect the probe sensitivity (volts!tesla). It should be noted that the voltage injection technique can also be used as a means of verifying the calibration of all ranges of the magnetic field meter.
A.1.3 Comparison with reference magnetic field meter
A third method for calibrating instrumentation is performed by comparing field meter readings with a reference magnetic field meter that has previously been calibrated in a known magnetic field and/or by the voltage injection technique. With this approach, the field values determined with each sensor of the single-axis and three-axis field meters are compared with measurements obtained with the reference field meter in the same magnetic field (produced by a coil system). It is assumed that (1) the sensor dimensions of the meter being calibrated and the reference meter are comparable, or the field uniformity is sufficiently great that the averaging effects of the sensors (over their cross-sectional areas) are not significantly different, (2) the pass-band of the field meter being calibrated is comparable to that of the reference meter, and (3) background magnetic fields (typically unstable) do not make significant contributions to the calibration field. Comparisons are made at field levels and frequencies of interest.
Alternatively, the reference magnetic field meter may be used to verify the calibration of a coil system used for calibration purposes.
NOTE 1 Comparison of the magnetic fIeld meter readings with the calibration field values enables the determination of correction factors that should be applied to readings wtien measurements are performed. Alternatively, the comparisons allow corrective adjustments to be made in the detector circuit, In either case, the uncertainty associated with the above calibration processes is equal to the uncertainty in the value of the calibration field values (once the corrections have been made) combined with uncertainties related to the stability and resolution of the field meter readings.