Linear motor for extended travel

A linear motor comprising:

• an armature and a stator moveable relative to one another along a path of movement and having, respectively, first and second sets of magnetic flux generators,
• the flux generators of the first set being arranged in pairs uniformly spaced at a predetermined pole pitch along the length of said path, the flux generators of each pair being disposed in an opposed relationship to one another to opposite sides of said path and producing magnetic fields across and defining therebetween at least one stator magnetic circuit air gap extending over the length of said path, the polarities of the fields alternating between successive flux generator pairs along said air gap,
• the second set of flux generators comprising at least two drive coils disposed in said magnetic fields, each drive coil comprising a contiguous set of cylindrical sub-coils, the sub-coils of each set having a pole pitch substantially equal to that of the first set of flux generators, the sub-coils of the respective drive coils being disposed such that their axes are directed laterally of said path so as to extend across said gap and such that the axes of the sub-coils of one set are offset longitudinally of the path from those of the other set by an amount differing from said pole pitch,
• the sub-coils of a drive coil being arranged such that their axes are spaced apart longitudinally of the motor by a distance substantially equal to their maximum diameters and being energisable such that the mutually adjacent portions of the windings of longitudinally successive sub-coils of a coil produce fields of the same polarity.