Smoother thrust on multi-polar type linear DC motor

As compared with a mono-polar type linear DC motor (LDM), multi-polar type LDM can have a longer stroke and more thrust with thin shape. However, there is thrust ripple on the multi-polar LDM. In this paper, a design to prevent thrust ripple is discussed. In order to achieve smoother thrust on multi-polar type LDM, the structure of the LDM is set as a 2-phase coil type. This paper clarifies that the thrust ripple of the LDM has a minimum value of 1.68%, a pole pitch of 15 mm, a coil width of 12 mm and a permanent magnet width of 10 mm.