Lifting electromagnet with pole face winding - has winding arranged in spiral form to give alternate pole polarity between grooves

摘要

The windings are embedded in spiral slots in the active pole material to give two branches. Each is a spiral lying within the other, and they are joined at the centre. Current passing from terminal to terminal thus flows in towards the centre and then out again thereby magnetising the pole material to give a successive sequence of alternate poles across the magnet face. The winding may be excited with either direct or alternating current. By employing three branches suitably displaced a three phase excitation may be used. The magnetic field is of approximately equal strength over the whole face of the lifting face.