Abstract: A marking (7) that indicates inherent information about a stator (2), is formed of recesses inscribed at a predetermined position on the outer circumferential surface of a laminated iron core (21) of the stator (2), by melting a magnetic thin plate with a laser beam. The marking (7) is formed of recesses in the outer circumferential surface of the laminated iron core (21), i.e., in the outer circumferential surface, at the laminated side of the magnetic thin plate, of the laminated iron core (21). Accordingly, friction or the like does not peel off the marking.

Abstract: A marking (7) that indicates inherent information about a stator (2) is formed of recesses inscribed at a predetermined position on the outer circumferential surface of a laminated iron core (21) of the stator (2), by melting a magnetic thin plate by means of a laser beam. The marking (7) is formed of recesses in the outer circumferential surface of the laminated iron core (21), i.e., in the outer circumferential surface, at the laminated side of the magnetic thin plate, of the laminated iron core (21); therefore, friction or the like does not peel off the marking. The inherent information about a stator is information, such as information that in which place of which factory the stator has been manufactured, which is utilized for a product analysis in the case where, after being utilized as a product, the manufacturer obtains the stator.

Abstract: Grooves are formed on a rotor by rotor holders for holding a rotor at both ends of a rotary shaft thereof, a groove rolling die for forming grooves in the outer surfaces of the field cores of the rotor, and a holder die having a groove pattern in conformity with a pattern of the grooves that are formed in the outer surfaces of the field cores by the groove rolling die. When the grooves are formed, the grooves are uniform in depth over the entire length of the magnetic poles from the root to the top, thereby preventing the eddy-current loss reduction effect from being deteriorated.