IEC 61308:2026

IEC 61308:2026 specifies test methods for the determination of useful 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, 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.
For equipment working in designated ISM bands, it is a legal requirement that the frequency remains within the ISM bands according to CISPR 11, 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.
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 can be different from that obtained with the test load specified in this document.
This document relates to equipment normally operating under continuous rated conditions.
This third edition cancels and replaces the second edition published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) adaptation and alignment to the principles in more recent editions of IEC 60519-1 and IEC 60519-6;
b) more detailed descriptions of, in particular, the calorimetric load test and output power evaluation for dielectic plastic welders.