DC-Biasing Test on the LCM and Computational Results
The square LCM shown in Figure 5.26(a)-(b) was made by the Tianwei Group, Baod- ing, China. Two coils entwine the magnetic core, both with 312 turns. One is the exciting coil, and the other is the search coil.
B-H Curve of the LCM
The ferromagnetic core is laminated by electric sheets, between which there are minor gaps. Therefore, the LCM may have different magnetizing characteristics, compared with the steel strips. Some measurements are carried out to obtain the accurate magnetizing curve of the LCM.
The exciting coil is fed by different alternating voltages. The induced voltage Uac and the exciting current I are measured by the power analyzer (WT-3000, Japan). The experimental data are manipulated as follows:
where ф is the magnetic flux in the magnetic core, Ncoii is the number of turns of the exciting coil, S is the cross-sectional area of the core, and l is the mean length of the magnetic circuit. The B-H curve (shown in Figure 5.26(c)) can be determined by solving the equations above.