Abstract: A moving coil linear motor having a central row of alternating, permanent magnets, with multi-phase, multi-pole coil assemblies located on both sides of the magnet row. Magnetic circuit completion material is located approximately the same height as the magnets and outside the coil assemblies. The coil assemblies are formed of a series of individual coils connected in a multi-phase, multi-pole relationship. At locations other than the coil assembly ends, the individual coils of a phase are adjacent and connected so that a current passes through them in a uniform direction. The individual coil total width is equal to the distance from a point on a magnet to the same point on the adjacent magnet, with the individual coil thickness being the total width divided by twice the number of phases. The coil assembly is coated with an epoxy to improve thermal mass and thermal conductivity and a phenolic to resist abrasion and the environment.

Abstract: A motion compensator for disposition between an offshore support and an offshore well string or the like movable with respect to the support comprises first and second compensator bodies interconnected with the support and the well string such that relative movement between the support and well string causes relative movement between the compensator bodies. The compensator bodies are further interconnected with each other for relative movement in generally vertical directional modes. A compressible fluid or the like is associated with the compensator bodies for resiliently resisting relative movement therebetween in a first directional mode. A position indicator associated with the compensator bodies comprises a flexible vessel having one end connected to one of the compensator bodies and the other end connected to the other compensator body generally below the one end.

Abstract: A moving coil linear motor having a central row of alternating, permanent magnets, with multi-phase, multi-pole coil assemblies located on both sides of the magnet row. Magnetic circuit completion material is located approximately the same height as the magnets and outside the coil assemblies. The coil assemblies are formed of a series of individual coils connected in a multi-phase, multi-pole relationship. At locations other than the coil assembly ends, the individual coils of a phase are adjacent and connected so that a current passes through them in a uniform direction. The individual coil total width is equal to the distance from a point on a magnet to the same point on the adjacent magnet, with the individual coil thickness being the total width divided by twice the number of phases. The coil assembly is coated with an epoxy to improve thermal mass and thermal conductivity and a phenolic to resist abrasion and the environment.