A dynamoelectric machine comprising: a stator comprising: a cylindrical stator core (15, 15A) in which slots that open radially inward are arrayed circumferentially; and a stator coil that is installed in said slots; a pair of frames (1, 2) that are each formed so as to have a bowl shape, and in each of which a receiving groove is formed around an entire circumference on an inner circumference of an opening of said bowl shape, outer circumferential portions at two axial ends of said stator core (15, 15A) fitting together with said receiving grooves so as to be held therebetween; a rotor that is disposed inside said stator core (15, 15A) so as to be coaxial with said stator core and that is rotatably supported by said pair of frames (1, 2); a plurality of through bolts that are arrayed circumferentially radially outside said stator core (15, 15A) so as to have an axial direction that is parallel to a central axis of said stator core, and that fasten and integrate said pair of frames (1, 2) that hold said stator core; and a cooling fan that is fixed to at least one axial end surface of said rotor, an air intake aperture (1a, 2a) being disposed through an end surface of said pair of frames (1, 2) near said cooling fan, and an air discharge aperture (1b, 2b) being disposed through a side surface of said pair of frames near said cooling fan, wherein said stator core (15, 15A) is configured by laminating and integrating thin magnetic plates (31, 31A), and has an outer circumferential surface that has a cylindrical surface; said receiving groove is constituted by: an annular axial surface that is constituted by a flat surface that is perpendicular to said central axis of said stator core (15, 15A); and a radial surface that is constituted by a cylindrical surface that is centered around said central axis; and surfaces of said thin magnetic plates (31, 31A) at two axial ends of said stator core (15, 15A) are held between each of said axial surfaces of said pair of frames (1, 2) in a state of close contact around an entire circumference, and characterized in that an insulating coating is coated only onto portions of said outer circumferential surface of said stator core that fit together with said radial surfaces, the surfaces of said thin magnetic plates (31, 31A) at two axial ends of said stator core (15, 15A) that are held between each of said axial surfaces of said pair of frames (1, 2) in a state of close contact around an entire circumference being metal surfaces. a stator comprising: a cylindrical stator core (15, 15A) in which slots that open radially inward are arrayed circumferentially; and a stator coil that is installed in said slots; a cylindrical stator core (15, 15A) in which slots that open radially inward are arrayed circumferentially; and a stator coil that is installed in said slots; a pair of frames (1, 2) that are each formed so as to have a bowl shape, and in each of which a receiving groove is formed around an entire circumference on an inner circumference of an opening of said bowl shape, outer circumferential portions at two axial ends of said stator core (15, 15A) fitting together with said receiving grooves so as to be held therebetween; a rotor that is disposed inside said stator core (15, 15A) so as to be coaxial with said stator core and that is rotatably supported by said pair of frames (1, 2); a plurality of through bolts that are arrayed circumferentially radially outside said stator core (15, 15A) so as to have an axial direction that is parallel to a central axis of said stator core, and that fasten and integrate said pair of frames (1, 2) that hold said stator core; and a cooling fan that is fixed to at least one axial end surface of said rotor, an air intake aperture (1a, 2a) being disposed through an end surface of said pair of frames (1, 2) near said cooling fan, and an air discharge aperture (1b, 2b) being disposed through a side surface of said pair of frames near said cooling fan, wherein said stator core (15, 15A) is configured by laminating and integrating thin magnetic plates (31, 31A), and has an outer circumferential surface that has a cylindrical surface; said receiving groove is constituted by: an annular axial surface that is constituted by a flat surface that is perpendicular to said central axis of said stator core (15, 15A); and a radial surface that is constituted by a cylindrical surface that is centered around said central axis; and an annular axial surface that is constituted by a flat surface that is perpendicular to said central axis of said stator core (15, 15A); and a radial surface that is constituted by a cylindrical surface that is centered around said central axis; and surfaces of said thin magnetic plates (31, 31A) at two axial ends of said stator core (15, 15A) are held between each of said axial surfaces of said pair of frames (1, 2) in a state of close contact around an entire circumference, and characterized in that an insulating coating is coated only onto portions of said outer circumferential surface of said stator core that fit together with said radial surfaces, the surfaces of said thin magnetic plates (31, 31A) at two axial ends of said stator core (15, 15A) that are held between each of said axial surfaces of said pair of frames (1, 2) in a state of close contact around an entire circumference being metal surfaces.