| 摘要 |
<p>The grooves on a plate surface separate the poles of the magnetic system, and the side of the plate facing the source of the magnetic field exhibits additional grooves which are offset from the other grooves. The spacing from the bottom of the groove to the surface of the plate, and the distance separating the main and the additional grooves as well as the overlap of the main and additional grooves are equal to each other. The blanks are placed on the plate and the coils are connected to the d.c. source ensuring a different polarity in adjacent cores. The magnetic flux generated by the coils passes through the base, cores, plate and the blank, the path determined by the geometry of the plate and by the size of the blank. If the blank overlaps two poles, the additional grooves prevent flux closure through the plate, while in the case of a small blank covering only one pole, the additional grroves (7) provide a path of two fluxes through the blank.</p> |
