Abstract: An electromagnetic brake (10) including a plurality of elastic members (25) which are arranged between an engagement surface of a brake pad (13) and an engagement surface of a hub (12) symmetrically about a center of rotation of the shaft (11). The biasing directions of the plurality of elastic members are in a rotational direction of the shaft.

Abstract: An electromagnetic brake (10) including a plurality of elastic members (25) which are arranged between an engagement surface of a brake pad (13) and an engagement surface of a hub (12) symmetrically about a center of rotation of the shaft (11). The biasing directions of the plurality of elastic members are in a rotational direction of the shaft.

Abstract: A synchronous electric motor including a rotor having a rotation axis, and a stator surrounding the rotor through a gap. The rotor includes a rotor core having an outer circumferential surface extending about the rotation axis and a plurality of permanent magnets attached to the rotor core to form plural poles along the outer circumferential surface of the rotor core. The outer circumferential surface of the rotor core is provided, at each pole, with a contour deviating from a circular arc and bulging out in a radial outward direction, as seen in a cross-section perpendicular to the rotation axis. The permanent magnets include a plurality of magnet sets individually assigned to the plural poles, each set including two or more permanent magnets. The contour of the outer circumferential surface of the rotor core, at each pole, has at least partially a shape represented by a hyperbolic cosine function or a secant function.

Abstract: In the control of a synchronous motor having a permanent magnet, an alternating current power supply voltage that is input to a power amplifier or a direct current link voltage of which input voltage is rectified is measured. A reactive current (a d-axis current) or a current control phase advance is changed, according to this power supply voltage. With this arrangement, reactive current control or current phase control can be carried out directly according to a change in the input power supply voltage. A motor control device includes a voltage measuring unit that measures a voltage supplied to a driving amplifier, and a current control unit that controls a current passed to a synchronous motor based on the measured voltage. The voltage measuring unit measures a voltage supplied to the amplifier. The current control unit controls a current that is passed to the synchronous motor, according to the measured voltage.

Abstract: A synchronous electric motor including a rotor having a rotation axis, and a stator surrounding the rotor through a gap. The rotor includes a rotor core having an outer circumferential surface extending about the rotation axis and a plurality of permanent magnets attached to the rotor core to form plural poles along the outer circumferential surface of the rotor core. The outer circumferential surface of the rotor core is provided, at each pole, with a contour deviating from a circular arc and bulging out in a radial outward direction, as seen in a cross-section perpendicular to the rotation axis. The permanent magnets include a plurality of magnet sets individually assigned to the plural poles, each set including two or more permanent magnets. The contour of the outer circumferential surface of the rotor core, at each pole, has at least partially a shape represented by a hyperbolic cosine function or a secant function.

Abstract: In the control of a synchronous motor having a permanent magnet, an alternating current power supply voltage that is input to a power amplifier or a direct current link voltage of which input voltage is rectified is measured. A reactive current (a d-axis current) or a current control phase advance is changed, according to this power supply voltage. With this arrangement, reactive current control or current phase control can be carried out directly according to a change in the input power supply voltage. A motor control device includes a voltage measuring unit that measures a voltage supplied to a driving amplifier, and a current control unit that controls a current passed to a synchronous motor based on the measured voltage. The voltage measuring unit measures a voltage supplied to the amplifier. The current control unit controls a current that is passed to the synchronous motor, according to the measured voltage.