Abstract: A permanent-magnet type rotating electrical machine, including a rotor including a plurality of magnetic poles arranged at an equal interval, and a stator including a plurality of teeth and a plurality of armature windings. A high frequency voltage different in frequency and amplitude from voltages for generating a torque is applied to the armature windings. A magnetic pole position of the rotor is estimated by using a current trajectory of a measured high frequency current. When dq transform is applied to the measured high frequency current, a current trajectory forms an ellipse on d and q axes. Angular variation ranges of a major axis of the ellipse with respect to a load current and a rotor position are set so as to acquire a predetermined position estimation resolution.

Abstract: The electric motor is the electric motor that includes a shaft part that rotates around a rotation shaft and a casing that accommodates at least part of the shaft part. A through hole is formed in the casing at a position that overlaps with the rotation shaft. A set screw is screwed into the through hole so as to close the through hole. An O-ring is interposed between the casing and the set screw so as to suppress intrusion of water and dust into the casing.

Abstract: The electric motor is the electric motor that includes a shaft part that rotates around a rotation shaft and a casing that accommodates at least part of the shaft part. A through hole is formed in the casing at a position that overlaps with the rotation shaft. A set screw is screwed into the through hole so as to close the through hole. An O-ring is interposed between the casing and the set screw so as to suppress intrusion of water and dust into the casing.

Abstract: A permanent-magnet type rotating electrical machine, including a rotor including a plurality of magnetic poles arranged at an equal interval, and a stator including a plurality of teeth and a plurality of armature windings. A high frequency voltage different in frequency and amplitude from voltages for generating a torque is applied to the armature windings. A magnetic pole position of the rotor is estimated by using a current trajectory of a measured high frequency current. When dq transform is applied to the measured high frequency current, a current trajectory forms an ellipse on d and q axes. Angular variation ranges of a major axis of the ellipse with respect to a load current and a rotor position are set so as to acquire a predetermined position estimation resolution.