A pump apparatus for pumping fluid, the apparatus comprising: - an electric motor configured to generate a rotational output, the electric motor comprising: - a rotor configured to rotate about a common axis, the rotor comprising a plurality of magnets, each magnet elongate and extending parallel with the common axis, the plurality of magnets annularly arrayed around the common axis; and - a stator configured to be electrically energized to generate magnetic flux that causes the rotor to rotate, the stator comprising a plurality of coils, the plurality of coils arrayed along the common axis, each coil of the plurality of coils coaxial with the common axis; - a drive configured to convert the rotational output from the electric motor into a linear reciprocating output; and - a fluid displacement member configured to receive the linear reciprocating output from the drive to be linearly reciprocated along the common axis to pump fluid; characterized in that the stator comprises a plurality of circular spur arrays that are arrayed along the common axis, each circular spur array (146a-146f) of the plurality of circular spur arrays respectively comprising a plurality of spurs that are arrayed in a circle coaxial with the common axis, all spurs of the plurality of spurs configured to be polarized simultaneously by a coil of the plurality of coils to generate flux to rotate the rotor relative to the stator; wherein the plurality of circular spur arrays are arranged in sets of paired circular spur arrays, each set of paired circular spur arrays has a first circular spur array and a second circular spur array, and each respective coil of the plurality of coils is located between a respective set of paired circular spur arrays; and wherein, for each set of paired circular spur arrays, a plurality of axial returns are disposed so that each axial return of the plurality of axial returns radially overlaps the first circular spur array of the set of paired circular spur arrays and the second circular spur array of the set of paired circular spur arrays to allow a flux circuit to polarize pairs of spurs on the first circular spur array and the second circular spur array. - an electric motor configured to generate a rotational output, the electric motor comprising: - a rotor configured to rotate about a common axis, the rotor comprising a plurality of magnets, each magnet elongate and extending parallel with the common axis, the plurality of magnets annularly arrayed around the common axis; and - a stator configured to be electrically energized to generate magnetic flux that causes the rotor to rotate, the stator comprising a plurality of coils, the plurality of coils arrayed along the common axis, each coil of the plurality of coils coaxial with the common axis; - a rotor configured to rotate about a common axis, the rotor comprising a plurality of magnets, each magnet elongate and extending parallel with the common axis, the plurality of magnets annularly arrayed around the common axis; and - a stator configured to be electrically energized to generate magnetic flux that causes the rotor to rotate, the stator comprising a plurality of coils, the plurality of coils arrayed along the common axis, each coil of the plurality of coils coaxial with the common axis; - a drive configured to convert the rotational output from the electric motor into a linear reciprocating output; and - a fluid displacement member configured to receive the linear reciprocating output from the drive to be linearly reciprocated along the common axis to pump fluid; characterized in that the stator comprises a plurality of circular spur arrays that are arrayed along the common axis, each circular spur array (146a-146f) of the plurality of circular spur arrays respectively comprising a plurality of spurs that are arrayed in a circle coaxial with the common axis, all spurs of the plurality of spurs configured to be polarized simultaneously by a coil of the plurality of coils to generate flux to rotate the rotor relative to the stator; wherein the plurality of circular spur arrays are arranged in sets of paired circular spur arrays, each set of paired circular spur arrays has a first circular spur array and a second circular spur array, and each respective coil of the plurality of coils is located between a respective set of paired circular spur arrays; and wherein, for each set of paired circular spur arrays, a plurality of axial returns are disposed so that each axial return of the plurality of axial returns radially overlaps the first circular spur array of the set of paired circular spur arrays and the second circular spur array of the set of paired circular spur arrays to allow a flux circuit to polarize pairs of spurs on the first circular spur array and the second circular spur array.