Abstract: Abnormality of a temperature sensor is detected by: calculating the amount of heat generated in a predetermined time period from an object of sensing temperature by the temperature sensor; calculating the amount of temperature change of the object of sensing temperature in the predetermined time period; calculating a coordinate value in a coordinate system represented by having the heat amount information calculated by the heat amount calculation step, on a coordinate axis, and having information on the amount of temperature change of the temperature sensor, calculated by the temperature change calculation step, on another coordinate axis; and detecting abnormality of the temperature sensor in the case where the coordinate value calculated by the coordinate value calculation step is included in a predetermined abnormality detection judgment area in the coordinate system continuously for a certain time.

Abstract: A magnet embedded rotor is provided in which permanent magnets are embedded in the iron core of the rotor at a fixed interval. Notch parts are formed at the first protruding part and both the sides of the first protruding parts on the outer face between salient poles in the iron core of the rotor correspond to the multiple permanent magnets. Non-magnetic parts for preventing the short circuit of magnetic flux are formed at both the edges of the permanent magnets. A bridge part between the non-magnetic parts and the notch parts are narrowed as much as possible to an extent to cause a magnetic saturation, and one or multiple of the second protruding part extending to the direction of the outer face are formed at the notch parts.

Abstract: A magnet embedded rotor is provided in which permanent magnets are embedded in the iron core of the rotor at a fixed interval. Notch parts are formed at the first protruding part and both the sides of the first protruding parts on the outer face between salient poles in the iron core of the rotor correspond to the multiple permanent magnets. Non-magnetic parts for preventing the short circuit of magnetic flux are formed at both the edges of the permanent magnets. A bridge part between the non-magnetic parts and the notch parts are narrowed as much as possible to an extent to cause a magnetic saturation, and one or multiple of the second protruding part extending to the direction of the outer face are formed at the notch parts.

Abstract: In a permanent magnet rotor type electric motor in which a permanent magnet is embedded in a rotor, a permanent magnet used for a magnetic pole of one polarity in a rotor core and another permanent magnet used for a magnetic pole of the other polarity have different configurations and materials from each other, so that the selecting range for the magnetic flux density and the reluctance torque of the permanent magnet rotor type electric motor can be increased.

Abstract: In an electric motor, such as a DC brushless motor or the like, having a permanent magnet in a rotor, each magnetic pole is formed of three permanent magnets, and the permanent magnets are made of at least two kinds of magnetic materials represented by ferrite magnet and rare-earth magnet. Thus, in a permanent magnet rotor type electric motor, a reluctance torque and a magnetic flux density can be selectively established, and cost is reasonable, corresponding to the quality.

Abstract: A permanent magnet rotor type electric motor is formed of a stator core generating a rotation magnetic field, and a rotor core rotationally situated inside the stator core. The rotor core includes a first core member for generating a magnet torque, permanent magnets embedded in the first core member for forming magnetic poles, and a second core member for generating a reluctance torque without having a permanent magnet therein. The second core member is coaxially united with the first core member so that the rotor core is divided into the first core member for generating the magnet torque and the second core member for generating the reluctance torque.

Abstract: In a permanent magnet rotor type electric motor having a stator core generating a rotation magnetic field and provided therein with a rotor core in which each magnetic pole is formed by a permanent magnet, the rotor core is fabricated by coaxially and unitedly joining a first core member and a second core member, in which a first permanent magnet of a predetermined cross-section shape is embedded per magnetic pole in the first core member, and a second permanent magnet which is made of a different material and has a different cross-section shape from those of the first permanent magnet is embedded per magnetic pole in the second core member, thereby achieving the permanent magnet rotor type electric motor having the performance and size appropriate for the intended use.