Abstract: A linear electromagnetic machine comprises two relatively movable members with an array of coils on one member and a plurality of magnets of alternating polarity on the other whereby to generate a magnetic field which intersects a current flowing in the coils in such a way as to give rise to a mechanical force between the two members. The coils are encased within an outer casing having a plurality of generally elongate fins to encourage the transfer of heat from the coils to the environment. The relative positions of the coils and the magnets sensed by a position transducer and the coils are grouped in modular units which can be supplied independently by one or more power supply and control unit such that coils can be selectively energized in dependence on the relative positions of the magnets and the coils.