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 +or-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 I/sup 2/R 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/sub 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 degrees C can be detected by the system.<
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