Effects of eddy currents in the specimen in a single sheet tester on measurement errors

The most favorable construction of the yoke of a single-sheet tester (SST) has been studied by measurements and numerical analysis. It is shown that the eddy currents in a specimen affect the measurement error of the SST, and the error increases with increase in the overhang length and with decrease in the distance between yokes. It is concluded that the single-yoke-type tester has a large error due to eddy currents and that the double-yoke tester is superior. If a single-yoke-type SST is used, the lengths of the B and H coils should be chosen in such a way that the measured power loss is not affected by the eddy currents in the specimen