Abstract: To provide a battery-driven motor and a motor-driven system that achieve high output density without compromising overall system efficiency, a battery-driven motor is supplied electric power from a battery via an inverter to drive a load, wherein current supplied from the battery is 3.0 C or more when driven at maximum output, the battery-driven motor including a stator core (12) provided with an electrical steel sheet as an iron core material that has a magnetic flux density of 1.65 T or more at a magnetic field strength of 5,000 A/m and an iron loss of 40.0 W/kg or less under sinusoidal excitation of 1 kHz-1.0 T.

Abstract: A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): MII3MIII4(XVO4)6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.

Abstract: Provided is a miniaturized motor core with multiple poles for use in motors that require both output density and high efficiency. The motor core is formed by stacking a plurality of electrical steel sheets with a tooth width of 0.5 mm or more and 2.0 mm or less and 12 or more of slots arranged between the teeth, where the electrical steel sheet has an iron loss of 220 W/kg or less when excited at 1.0 T-3000 Hz.

Abstract: Provided is a laser machining method that causes no degradation in magnetic properties for thin electrical steel sheets. An electrical steel sheet machining method comprises machining an electrical steel sheet to a predetermined shape by melt-cutting the electrical steel sheet using a laser, wherein a scanning rate of the laser in the melt-cutting is 10000 mm/min or more.

Abstract: A motor comprising a steel sheet used as a core material of the motor, wherein the steel sheet includes a composition including: by mass %, 0.010% or less of C; 2.0% to 7.0% of Si; 2.0% or less of Al; 0.05% to 1.0% of Mn; 0.005% or less of S; 0.005% or less of N; and balance Fe and inevitable impurities; the steel sheet includes a magnetic flux density changing area where a change ?B in magnetic flux density to a change ?H=50 A/m in a magnetic field, is equal to or higher than 0.50 T; a thickness of the steel sheet is 0.05 mm to 0.20 mm; and an eddy-current loss of the steel sheet, at 1000 Hz?1.0 T, is equal to or less than 0.55 of a total iron loss.

Abstract: Provided is a non-oriented electrical steel sheet having excellent adhesion with an insulating coating even if the thickness of the insulating coating is reduced. The non-oriented electrical steel sheet of the present disclosure has an insulating coating on at least one surface of the steel sheet, where the insulating coating has a P-concentrated layer on both a surface side and an interface side with a steel substrate, and a P concentration of the P-concentrated layer is higher than a P concentration in the steel substrate.

Abstract: A method for manufacturing a motor core includes a step of manufacturing a motor core by performing melt-cutting on an electrical steel sheet using heat input from a surface, the electrical steel sheet having an average thermal conductivity in depth positions from the surface to one-third depth of a sheet thickness lower than a thermal conductivity in a middle position in a sheet thickness direction by 30% or greater.

Abstract: Further lower iron loss can be achieved in a grain-oriented electrical steel sheet including: a predetermined film mainly composed of forsterite on a front and back surfaces thereof; and a plurality of grooves on the front surface thereof, in which the plurality of grooves have an average depth of 6% or more of a thickness of the steel sheet and are spaced a distance of 1 mm to 15 mm from respective adjacent grooves, the steel sheet has a specific magnetic permeability ?r15/50 of 35000 or more when subjected to alternating current magnetization at a frequency of 50 Hz and a maximum magnetic flux density of 1.5 T, and the steel sheet includes isolated parts having a presence frequency of 0.3/?m or less, the isolated parts being separated from a continuous part of the film in an interface between the steel sheet and the film in a cross section orthogonal to the rolling direction of the steel sheet.

Abstract: A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): MII3MIII4(XVO4)6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.

Abstract: A motor comprising a steel sheet used as a core material of the motor, wherein the steel sheet includes a composition including: by mass %, 0.010% or less of C; 2.0% to 7.0% of Si; 2.0% or less of Al; 0.05% to 1.0% of Mn; 0.005% or less of S; 0.005% or less of N; and balance Fe and inevitable impurities; the steel sheet includes a magnetic flux density changing area where a change ?B in magnetic flux density to a change ?H=50 A/m in a magnetic field, is equal to or higher than 0.50 T; a thickness of the steel sheet is 0.05 mm to 0.20 mm; and an eddy-current loss of the steel sheet, at 1000 Hz?1.0 T, is equal to or less than 0.55 of a total iron loss.

Abstract: Further lower iron loss can be achieved in a grain-oriented electrical steel sheet including: a predetermined film mainly composed of forsterite on a front and back surfaces thereof; and a plurality of grooves on the front surface thereof, in which the plurality of grooves have an average depth of 6% or more of a thickness of the steel sheet and are spaced a distance of 1 mm to 15 mm from respective adjacent grooves, the steel sheet has a specific magnetic permeability ?r15/50 of 35000 or more when subjected to alternating current magnetization at a frequency of 50 Hz and a maximum magnetic flux density of 1.5 T, and the steel sheet includes isolated parts having a presence frequency of 0.3/?m or less, the isolated parts being separated from a continuous part of the film in an interface between the steel sheet and the film in a cross section orthogonal to the rolling direction of the steel sheet.