prEN IEC 61308:2025

This International Standard specifies test methods for the determination of available high frequency
power output in equipment for industrial heating and processing of materials. It is in particular applicable
to HF generators made available to users as separate units.
This document is basically applicable to equipment operating in the frequency range 100 kHz to 300
MHz, as defined in IEC 60519-1:2020, with the following limitations.
– This document does not apply to induction heating, which it is possible to carry out in the lower part
of the specified frequency band.
– The ISM centre frequencies for dielectric heating and processing of industrial interest are
narrow bands about 6,78 MHz, 13,56 MHz, 27,12 MHz and 40,68 MHz.
– This document is not applicable to:
• appliances for household and similar use;
• commercial use;
• laboratory use;
• medical high frequency equipment.
NOTE 1 The following criteria are suitable for determination of the classification as industrial equipment:
– commercial equipment is typically designed and planned for series production of many identical units,
– industrial equipment is typically produced in small series or even as single units. The processed goods are consumed or
ready for final use at the end of the heating process.
NOTE 2 Heating a workload with dielectric parameters which change significantly in time and/or with temperature, the value of
the output power obtained with the actual charge may be different from that obtained with the test load specified in this standard.
NOTE 3 For equipment working in designated ISM bands it is required that the frequency remains within the ISM bands
according to CISPR11, but the resonant frequency of the circuit varies with the change of dielectric parameters of the load.
Therefore, the value of the mean output power in the work cycle can be much lower than the value obtained under the test
conditions. This value depends upon the response of the tuning system.
This standard relates to equipment normally operating under continuous rated conditions.