A permanent magnet direct current electric motor including a stator core, a stator winding for a stator core, and a magnetic rotor rotatably mounted inside the stator, in which the stator core comprises a closely wound helical coil of ferromagnetic wire, and in which the stator winding is positioned between the stator core and the rotor.
A slot-less motor for super high speed driving by which a stator coil is not detached from a housing even at a super high speed of rotation of the slot-less motor, and an air gap flux density for super high speed driving is easily obtained and is uniformly maintained, the slot-less motor employing a stator coil bonded to an inner surface of a housing for maintaining an air gap with a rotor magnet fixed to a rotor shaft to form a stator, wherein the slot-less motor comprises a cylindrical stator ring made of material with low relative magnetic permeability and disposed between a magnet and a stator coil in order to maintain an air gap flux density appropriate for super high speed rotation, and for being distanced from the magnet at a predetermined space to press the stator coil and to be fixed by a coupling unit for fixation and keep within a predetermined space.
A unitary amorphous metal magnetic component for an axial flux electric machine such as a motor or generator is formed from a spirally wound annular cylinder of ferromagnetic amorphous metal strips. The cylinder is adhesively bonded and provided with a plurality of slots formed in one of the annular faces of the cylinder and extending from the inner diameter to the outer diameter of the cylinder. The component is preferably employed in constructing a high efficiency, axial flux electric motor. When operated at an excitation frequency "f" to a peak induction level B.sub.max the unitary amorphous metal magnetic component has a core-loss less than "L" wherein L is given by the formula L=0.0074f(B.sub.max).sup.1.3+0.000282f.sup.1.5(B.sub.max).sup.2.4, the core loss, excitation frequency and peak induction level being measured in watts per kilogram, hertz, and teslas, respectively.