A lifter with electro-permanent magnets is provided. It has an external bearing structure closed at the bottom by a plate, provided with a heat shield, and pole pieces secured under the respective poles and protruding from the bottom plate. Each of the electro-permanent magnets has a reversible magnet arranged on top of one of the poles, of a fixed polarization magnet formed by a plurality of blocks placed along the lateral faces of the pole and of a coil arranged around the reversible magnet to cause the reversal of the polarization of the latter by means of an electrical pulse. An airtight air gap between 1 and 4 mm high is formed between each pole piece and the respective pole through the interposition of a plate of thermal insulation material that resists high temperatures provided at each pole with a rectangular window slightly smaller in size than the pole itself, with the top sides of the pole pieces and/or the bottom sides of the poles being provided with peripheral recesses suitable to act as seats for the positioning of the plate.

When at least one of a value a detected output current to a magnet and a magnet load defined by the following formula is equal to or larger than a threshold value predetermined for the value of the detected output current or a threshold value predetermined for the magnet load, a controller constituting a control device outputs, to a control circuit, a command to decrease voltage applied to the magnet from next attracting operation. Magnet load=excitation ratio×I×V . . . ; wherein excitation ratio: excitation time/(excitation time+non-excitation time); I: value of the output current; V: voltage applied to a lifting magnet.

A rope hoist which hoists and lowers a cargo via a wire rope includes: a frame structure which rotatably supports a wheel; a rope drum mechanism which is provided on one side of the frame structure in a width direction, and includes a drum motor which rotates the rope drum; a counterweight which is provided on another side of the frame structure in the width direction and is arranged in a state of having a space with respect to the frame structure; and a control unit which is attached to a side of the counterweight opposite to the rope drum mechanism in the width direction and inverter-controls the drum motor, to the rope drum mechanism side of the counterweight, a braking resistor part which processes regenerative electric power in the inverter control is attached in a state of being located in the space.

Motor control architecture including a travel, a hoist, and a controller is disclosed. The travel disposed on a main rail having an auxiliary-encoder includes a master-driver and a slave-driver for driving two motors. Each motor has a main-encoder. The hoist drives a rope and calculates a rope length continuously. The controller calculates an anti-sway position command based on the rope-length and a position command. The two drivers perform a full closed-loop computation based on a feedback of one main-encoder, a feedback of the auxiliary-encoder, and the anti-sway position command. Wherein, the master-driver controls one motor based on a speed command generated by the full closed-loop computation and the slave-driver follows the speed command and a torque command of the master-driver to drive another motor; or the two drivers compensate the torque command based on an error value between the feedback of one main-encoder and the feedback of the auxiliary-encoder.

When at least one of a value a detected output current to a magnet and a magnet load defined by the following formula (1) is equal to or larger than a threshold value predetermined for the value of the detected output current or a threshold value predetermined for the magnet load, a controller constituting a control device outputs, to a control circuit, a command to decrease voltage applied to the magnet from next attracting operation. Magnet load=excitation ratioIV . . . (1); in which excitation ratio: excitation time/(excitation time+non-excitation time); I: value of the output current; V: voltage applied to a lifting magnet.

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.

Motor control architecture including a travel, a hoist, and a controller is disclosed. The travel disposed on a main rail having an auxiliary-encoder includes a master-driver and a slave-driver for driving two motors. Each motor has a main-encoder. The hoist drives a rope and calculates a rope length continuously. The controller calculates an anti-sway position command based on the rope-length and a position command. The two drivers perform a full closed-loop computation based on a feedback of one main-encoder, a feedback of the auxiliary-encoder, and the anti-sway position command. Wherein, the master-driver controls one motor based on a speed command generated by the full closed-loop computation and the slave-driver follows the speed command and a torque command of the master-driver to drive another motor; or the two drivers compensate the torque command based on an error value between the feedback of one main-encoder and the feedback of the auxiliary-encoder.

A lifter with electro-permanent magnets is provided. It has an external bearing structure closed at the bottom by a plate, provided with a heat shield, and pole pieces secured under the respective poles and protruding from the bottom plate. Each of the electro-permanent magnets has a reversible magnet arranged on top of one of the poles, of a fixed polarization magnet formed by a plurality of blocks placed along the lateral faces of the pole and of a coil arranged around the reversible magnet to cause the reversal of the polarization of the latter by means of an electrical pulse. An airtight air gap between 1 and 4 mm high is formed between each pole piece and the respective pole through the interposition of a plate of thermal insulation material that resists high temperatures provided at each pole with a rectangular window slightly smaller in size than the pole itself, with the top sides of the pole pieces and/or the bottom sides of the poles being provided with peripheral recesses suitable to act as seats for the positioning of the plate.

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.

A rope hoist which hoists and lowers a cargo via a wire rope includes: a frame structure which rotatably supports a wheel; a rope drum mechanism which is provided on one side of the frame structure in a width direction, and includes a drum motor which rotates the rope drum; a counterweight which is provided on another side of the frame structure in the width direction and is arranged in a state of having a space with respect to the frame structure; and a control unit which is attached to a side of the counterweight opposite to the rope drum mechanism in the width direction and inverter-controls the drum motor, to the rope drum mechanism side of the counterweight, a braking resistor part which processes regenerative electric power in the inverter control is attached in a state of being located in the space.