Fuji Electric Fa Components & Systems Co., Ltd.

Fuji Electric Co., Ltd.

Nippon Steel Corporation

Takahiro Taguchi

Kenji Suzuki

Akira Morita

Naoyuki Matsuo

Yasuhiro Naka

Kouetsu Takaya

Satoshi Yamazaki

Takashi Tsutsumi

Tsuyoshi Yamazaki

Satoshi Machida

Kosuke Ishibashi

Kokichi Okamoto

Shuhei Kasahara

Masahiro Motonobu

This electric furnace includes one or more upper electrodes, one or more bottom-blowing tuyeres, a mechanical stirrer equipped with an impeller, and a charging device which injects an iron oxide-containing iron raw material.

Electric furnace and method for melting and reducing iron oxide-containing iron raw material

An operation coil drive device includes a drive control unit to perform control to set, for a semiconductor switching element to switch on and off the source voltage applied to an operation coil of a magnetic contactor, a larger ON/OFF time ratio for a circuit-closing control and a smaller ON/OFF time ratio for a holding control, wherein the drive control unit includes: a circuit-closing-control inductance calculation unit to calculate an inductance of the operation coil immediately after a start of the circuit-closing control; a circuit-closing-control resistance value calculation unit to calculate a direct current resistance value of the operation coil based on the calculation result; and a circuit-closing-control switching correction unit to correct the ON/OFF time ratio of the semiconductor switching element for the circuit-closing control based on the calculation result.

Operation coil drive device for magnetic contactor

Operation coil drive device of electromagnetic contactor includes current detector and drive controller. The detector, when switching control is performed on operation coils of the contactor, detects coil current flowing through the coils. The controller controls an on/off time ratio of a semiconductor switching element wherein the on/off time ratio during close circuit control becomes larger than the on/off time ratio during holding control. Power supply voltage is switchingly applied to the coils at the on/off time ratio. The controller includes a determination locus setter and a close circuit state determiner. The setter sets a determination locus that continuously increases along a change locus of detected coil current during close circuit control. The determiner determines a contact point close circuit state by contact of a movable contact to a fixed contact based on deviation between the determination locus by the setter and the detected coil current detected.

Operation coil drive device of electromagnetic contactor

A method of mounting electronic parts on a surface mounting substrate includes a step of forming a film resist layer by applying a resist with a film coating device to amounting surface of a surface mounting substrate formed with a wiring pattern including a pair of lands to mount an electronic part; precuring the formed film resist layer; exposing, by using a mask, inner side regions of the film resist layer, the inner side regions defining the exposure regions and another region defining non-exposure region; etching away the film resist layer in the non-exposure regions and forming film resist layers in the inner side regions; post curing the film resist layers; printing solder pastes in regions on the lands excluding the inner side regions; and placing the electronic part on the solder pastes and reflow-soldering thereon.

Method of mounting electronic parts on surface mounting substrate using a film resist standoff

An electromagnetic coil drive device has a semiconductor switch connected in series with an electromagnetic coil for controlling a current supplied to the coil; a capacitor; a comparator for comparing a voltage to charge and discharge the capacitor with two different voltages, for generating a signal to operate on-off of the semiconductor switch in accordance with a result of a comparison; a first charging circuit to charge the capacitor based on a voltage applied to the coil; and a discharging circuit to discharge the capacitor. The first charging circuit has a first resistor and at least one compensating circuit connected in parallel with the first resistor; and a resistor and a Zener diode are connected in series in the compensating circuit.

Electromagnetic coil drive device

An electromagnetic contactor has a pair of fixed contacts disposed and fixed maintaining a predetermined interval; a movable contact disposed to be capable of contacting to and separating from the pair of fixed contacts; an electromagnet unit to drive the movable contact; and a drive circuit driving the electromagnet unit. The electromagnet unit includes at least a movable plunger urged by a return spring, a coil to move the movable plunger, and a ring-form permanent magnet magnetized in a moving direction of the movable plunger. The drive circuit includes a power source to supply power to the coil; a pulse drive circuit to output and supply to the coil an engage pulse causing the movable plunger to perform an attracting operation and a hold pulse maintaining the attracting operation when the movable plunger is subject to the attracting operation, and a flywheel circuit having a semiconductor switching element.

Growing community of inventors

Kounosu, Japan

Takahiro Taguchi