A novel rare-earth permanent magnet lifting device

It is becoming increasingly essential to carry out a theoretical analysis using finite element method (FEM) for a design problem before the unit is actually constructed. This method of solving problems is helpful in the sense that one can find a close approximation to the prototype solution before it is actually built. This saves an enormous amount of time and money because difficulties in the design can be detected and rectified at an early stage before the device is constructed and hence avoids any trial and error prototypes. The FEM analysis also helps in choosing the right material for the design. This paper describes an analysis of flux in a novel rare-earth permanent magnet lifting device by using the finite element method. Ferrite and Alnico magnets had been used in the past in permanent magnet lifting devices. These magnets are extremely cheap compared to the neodymium-boron-iron magnets, but a relatively large volume of these magnets is required to achieve a given performance. A careful study of the flux distribution in the prototype is first carried out using a two-dimensional commercial FEM electromagnetic field software package. The two-dimensional analysis informs the designer whether any improvements are necessary. Then the three-dimensional analysis is carried out in order to fully optimise the design