Specifications

B-field Exposure From Induction Cooking Appliances 26
Figure 19: Time-domain signals of the alternating magnetic field generated by appli-
ance 3. Graphs a) and b) correspond to the heat settings 4 and 12. The fundamental signal
frequencies are 62.7 kHz and 21.7 kHz, respectively. The signal rms-value increases approxi-
mately by a factor of 4 for heat settings from 4 to 12. Graphs c) and d) correspond to the heat
settings 6 and 10 and show a signal envelope with a frequency of 300 Hz that remains constant
for all heat settings. Graphs e) and f) correspond to the heat settings 1 and 3. For heat settings
1 to 4, the signal is pulse-width modulated, with a frequency of approximately 0.5 Hz.
respectively), does not depend on the heat setting (see Table 5). It is assumed that the 100 Hz
envelope component is caused by the power supply operating from a single-phase 50 Hz mains,
and the 300 Hz component by the three-phase power supply. As shown in Figures 17 e) and f),
18 e) and f), and 19 e) and f), the signal is pulse-width modulated for all three appliances and
at the heat settings 1 to 4. The duty cycles (ratio of time on to total cycle time) are given in
Table 6.
4.2.2 Frequency-Domain Characterization
The determination of the spectral content of the B-field in the frequency range from 10 Hz to
400 kHz was performed with the Narda probe ELT-400 (analog signal output) connected to a