Abstract: Simplification of a device configuration and control is realized, which enables attraction and release by a magnet without using a battery. A magnet work machine includes a generator motor (8) driven by an engine (7); and an inverter (10) which controls a magnet (6) and the generator motor (8) such that the magnet (6) is energized by electric power from the generator motor (8) to attract metal scraps or the like, and during demagnetization for releasing metal scraps or the like, electric power applied to the magnet (6) is transmitted to the generator motor (8) as regenerative power so as to be consumed. The inverter (10) determines a torque of the generator motor (8) as a motor according to a voltage change of a main circuit based on a detected main circuit voltage so as to suppress the voltage change, and gives the torque as a command.

Abstract: Simplification of a device configuration and control is realized, which enables attraction and release by a magnet without using a battery. A magnet work machine includes a generator motor (8) driven by an engine (7); and an inverter (10) which controls a magnet (6) and the generator motor (8) such that the magnet (6) is energized by electric power from the generator motor (8) to attract metal scraps or the like, and during demagnetization for releasing metal scraps or the like, electric power applied to the magnet (6) is transmitted to the generator motor (8) as regenerative power so as to be consumed. The inverter (10) determines a torque of the generator motor (8) as a motor according to a voltage change of a main circuit based on a detected main circuit voltage so as to suppress the voltage change, and gives the torque as a command.

Abstract: A weft yarn feed device (1) comprises a measuring and storing drum (7) for storing a predetermined length of a weft yarn (4) thereon for picking operation, a rotary yarn guide (6) for winding the weft yarn (4) on the measuring and storing drum (7), a feed motor (8) for rotating the rotary yarn guide (6), a drive control unit (3) for controlling the operation of the feed motor (8), and a command control unit (2) which gives commands to the drive control unit (3). The length of the weft yarn (4) wound on the measuring and storing drum (7) is detected accurately on the basis of the relation between the number of rotation of the rotary yarn guide (6) and that of the crankshaft of the loom, and a detection signal indicating the length of the weft yarn (4) wound on the measuring and storing drum (7) is fed back to the command control unit (2) to control the feed motor ( 8) properly for winding a predetermined length of the weft yarn (4) on the measuring and storing drum.