A stator assembly for an electric machine includes stator teeth connected to a stator yoke to form a stator core. Adjacent teeth define a stator slot. Stator windings are disposed within the slot. A molding material fills the slot around the windings, providing a desired thermoelectrical performance level at different slot regions, including electrical insulation, thermal conductivity, and/or electrostatic shielding levels. A method insulates the stator assembly by inserting a molding tool(s) into the slot to define a void volume, filling the void volume with the dielectric molding material, and curing the dielectric molding material to form a slot liner layer adjacent to the tooth walls. A slot opening between adjacent teeth is filled with an electrically-conductive resin to form an electrostatic shielding layer. An electrical system includes an AC voltage bus connected to a power inverter module and to the electric machine having the above-described stator assembly.

A motor comprising a shaft, an array of stator assemblies rigidly attached to the shaft, each stator assembly includes a stator yoke having a toroid shape fixed around the shaft and having a number of slots at radial and axis directional faces with windings within the slots of the stator yoke, and a rotor assembly rotatively attached to the shaft to enclose the array of stator assemblies, the rotor assembly has a rotor drum with sections, each section embraces one stator assembly, each section has two axial-flux permanent magnet arrays attached on axial-directional inner surfaces of the section and has one radial-flux permanent magnet array attached on a radial-directional inner surface of the section furthest from the shaft, wherein the axial-flux and the radial-flux permanent magnet arrays with the number of pole pairs equals the number of the stator slots plus or minus the number of stator winding pole pair.

A resin producing method is a method of producing a resin with which an insulating structure formed on an outer peripheral portion of a conductor is impregnated, the method including: a filler mixing step of mixing a nanofiller at a ratio of 15 wt % or more with an epoxy resin to form a mixture; a shear mixing step of causing the mixture to be subjected to shear mixing; a diluent mixing step of mixing a reactive diluent that reduces a viscosity of the epoxy resin, with the mixture after the shear mixing step; and a curing agent mixing step of mixing an acid anhydride curing agent with the mixture after the diluent mixing step.

A coil of a stator winding of an electric machine is formed of a number of windings, which are wound together with a number of layers of a mica tape, on which a number of layers of a cover tape are in turn wound. The coil is a three-dimensional form-wound coil. The mica tape has a bending stiffness of less than 50 N/m according to specification IEC 60371-2:2004 and a static friction coefficient between the top side and the bottom side thereof of less than 0.7 according to specification ISO 8295:1995.

A coil of a stator winding of an electric machine is formed of a number of windings, which are wound together with a number of layers of a mica tape, on which a number of layers of a cover tape are in turn wound. The coil is a three-dimensional form-wound coil. The mica tape has a bending stiffness of less than 50 N/m according to specification IEC 60371-2:2004 and a static friction coefficient between the top side and the bottom side thereof of less than 0.7 according to specification ISO 8295:1995.

A slot includes a coil housing portion having first and second side portions and a bottom portion. A first straight line connects first and second points which are boundaries between the bottom portion and the side portions. A slot opening has third and fourth points closest to the first and second side portions. A second straight line connects the first and third points. A third straight line connects the second and fourth points. A first region is surrounded by the first straight line and the bottom portion. A second region is surrounded by the second straight line and the first side portion, and is surrounded by the third straight line and the second side portion. A third region is surrounded by the three straight lines. Areas A1, A2 and A3 of the three regions and total cross-sectional areas S1, S2, S3 of coils therein satisfy (S1/A1)>(S2/A2)>(S3/A3).

A slot includes a coil housing portion having first and second side portions and a bottom portion. A first straight line connects first and second points which are boundaries between the bottom portion and the side portions. A slot opening has third and fourth points closest to the first and second side portions. A second straight line connects the first and third points. A third straight line connects the second and fourth points. A first region is surrounded by the first straight line and the bottom portion. A second region is surrounded by the second straight line and the first side portion, and is surrounded by the third straight line and the second side portion. A third region is surrounded by the three straight lines. Areas A1, A2 and A3 of the three regions and total cross-sectional areas S1, S2, S3 of coils therein satisfy (S1/A1)>(S2/A2)>(S3/A3).

A rotating electrical machine stator and a method for manufacturing a rotating electrical machine stator with high productivity. A rotating electrical machine stator includes a stator core having a slot; and a coil having a leg part including a held-in-slot part held in the slot and a portion extending from the held-in-slot part, and a resin foam is provided between an inner surface of the slot and an outer surface of the held-in-slot part facing the inner surface of the slot. The coil is formed by joining together a plurality of segment conductors each having a joint part, and a conductive joint material is disposed between a pair of joint parts facing each other in the slot.

A rotating electrical machine stator and a method for manufacturing a rotating electrical machine stator with high productivity. A rotating electrical machine stator includes a stator core having a slot; and a coil having a leg part including a held-in-slot part held in the slot and a portion extending from the held-in-slot part, and a resin foam is provided between an inner surface of the slot and an outer surface of the held-in-slot part facing the inner surface of the slot. The coil is formed by joining together a plurality of segment conductors each having a joint part, and a conductive joint material is disposed between a pair of joint parts facing each other in the slot.

To provide an insulated wire that can increase in a partial discharge starting voltage, prevent deterioration of an insulator, and not cause worsening of an occupancy ratio, a coil that uses the insulated wire, a variable-thickness insulating tape used in manufacture of the insulated wire, and a manufacturing method of the same. The above-described problem is solved by an insulated wire (10) for a coil, comprising a conductor (1), and insulating coatings (2, 3) provided on an outer periphery of the conductor (1). The insulated wire (10) is constituted by the thick insulating coating (3) for an area where voltage increases and partial discharge readily occurs, and the thin insulating coating (2) for an area where the voltage does not increase and partial discharge does not readily occur, when the coil is wound. The thick insulating coating (3) and the thin insulating coating (2) are repeatedly provided at desired intervals. The above-described problem is solved by a coil (40) obtained by winding such an insulated wire (10) and configured so that the insulating coating (3) of the insulated wire (10) in an area where partial discharge readily occurs is thick, and the insulating coating (2) of the insulated wire (10) in an area where partial discharge does not readily occur is thin.