| 摘要 |
<p>Magnet assembly consisting of a plurality of permanent magnets (1) each of which is wound around by a solenoid winding (4) which in use produces a field to force the permanent magnet (1) into positive or negative saturation in dependence on the direction of the solenoid current. Thus the overall magnetic moment of the assembly can be varied stepwise. Each permanent magnet (1) comprises a bundle of rods (2), made from a magnetic material such as chromium steel. The assembly is enclosed in a casing (3) of glass reinforced plastic to make the magnet assembly buoyant but not affect the magnetic fields produced. The magnet assembly can be constructed in the form of a 3-axis magnet to produce orthogonal magnetic fields. A number of the magnet assemblies can be connected in series to form a variable permanent magnet system producing a controllable magnetic field.</p> |
