ABSTRACT
Chapter 2 addresses three main approaches to the measurement of rotational losses in magnetically soft materials: torquemetric (based on mechanical effects), thermometric (temperature effects) and fieldmetric (electromagnetic effects). None of them is metrologically superior since they all merely employ different physical quantities related to the same underlying phenomenon. They are not competing but rather complementing each other and allow scientific cross-validation of the measured values and achieved reproducibility of the results. Under carefully controlled conditions, the agreement between different methods is good, considering the variety of the measured physical quantities. A fourth method that could be described as wattmetric (electromagnetic effects detected as electric effects) was attempted by some researchers. Nowadays, this method does not seem to be used due to problems with excitation level and magnetisation uniformity. This method is briefly explained for the sake of completeness because it evolved from the standardised measurements under alternating magnetisation.
