Specifications

B-field Exposure From Induction Cooking Appliances 18
Worst-case set of pots A worst-case set of pots has been selected (see Figure 11), composed
of pots 8, 7, 13 and 2 with bottom diameters of 14 cm, 14 cm, 14.5 cm and 15 cm, respectively.
Figure 11: Worst-case set of pots.
3.4 B-field Narda Sensor ELT-400
The magnetic flux density (B-field) was measured using the Narda exposure level tester ELT-400
(see Figure 12).
Figure 12: Narda exposure level tester ELT-400.
The probe is especially designed for investigating the magnetic field produced by household
equipment and other electrical devices. The DASY4 system was extended to enable use with
the Narda probe ELT-400. This involved mechanical, electrical and software modifications.
The reference test method described in EN50366 is implemented in the Narda probe, and the
measured B-field is given in [µT], or as a percentage of the ICNIRP guideline [2]. The 3D-
sensor system covers the frequency range from 1-30 Hz to 400 kHz. The B-field is measured
using three orthogonal coils with a common center point (allowing isotropic measurement).
The cross sectional area is 100 cm
2
(standard-compliant), and the probe’s external diameter is
125 mm. The signal voltages in the coils are digitized and evaluated by a digital signal processor
(DSP), which calculates in real-time the root-mean-square (rms) value of the B-field, according
to EN50366 [4]. The rms-value of the magnetic flux density B is calculated from the rms-values
of each of the three measurement axes (B
x
, B
y
and B
z
) according to Equation (1).
B =
q
B
2
x
+ B
2
y
+ B
2
z
(1)