Computerised DC bridge method of thermistor measurement of localised power loss in magnetic materials

A fully automated localized power loss measurement system with a repeatability of ±1% was designed and constructed. A thermistor and associated electronics were used to measure the localized power loss from the initial rate of rise of temperature in magnetic materials. The designed system was calibrated by using I²R Joule loss obtained from a known DC current through a copper strip sample. The system was capable of detecting the localized power loss not only on conventional silicon-iron laminations but also on a single amorphous ribbon magnetized in the flux density range of 1 T to B _s in a frequency range of 50 Hz to 5 kHz. The quality of the system was assessed by comparing the results to data obtained from other conventional systems. A change in temperature on the order of 0.0002°C can be detected by the system