B-H loops (hysteresis loops) measured on a toroidal core, made from grain-oriented electrical steel grade M4. The core was cut and lapped. Blue curve shows the B-H loop with the lapped faces touching. Red curve shows data measured for the same core, with an air gap of 0.07 mm (plastic shim) introduced between the lapped faces.
B-H loops measured at 1.7T, 50Hz. Power loss was 1.49 W/kg without air gap, and 1.45 W/kg with the air gap, so very little change comparing to great changes of the shape of the loop.
Data measured by Stan Zurek on measurement system A.
air_gap_in_bh_loop.png
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