Abstract: An electronic device is configured to be coupled to a capacitor bank in a power system network. The electronic device includes a first switch, a second switch, and a damping circuit in series with the second switch. The damping circuit includes a passive damping circuit and a thyristor that is in parallel with the passive damping circuit. Related methods and circuits are also described.

Abstract: An apparatus and method to machine cavities in die blanks having little to no taper. The apparatus includes an electrode tool (200) including intersecting walls coated with electrically insulating coating (258), an erosion face (204) comprising a cross section of the walls exposed through the electrically insulating coating, and a channel formed by the walls to supply electrolyte to the erosion face, the channels defined by interior surfaces of the walls and having an opening formed by edges of the erosion face. The method includes pulsed electrochemical machining a work piece with the electrode tool.

Abstract: A method of manufacturing a gear, the method includes applying a first charge to a workpiece and applying a second, opposite charge to an electrochemical machining (ECM) attachment, the ECM attachment having a pattern. The method further includes simultaneously forming a plurality of surfaces of a gear tooth in the workpiece using the pattern of the ECM attachment while applying the first charge to the workpiece and applying the second charge to the ECM attachment and turning the workpiece and the ECM attachment in opposite rotational directions. The plurality of surfaces includes at least one end face and a top land of the gear tooth.

Abstract: A position control apparatus is provided that can perform accurate nonlinear compensation control immediately after the apparatus is activated. At a time of acceleration, a signal amplification ratio is calculated and designated for each signal vector element based on information related to acceleration/deceleration at a starting time and the structure of a signal vector that is determined for a target plant, and as a result, a signal vector for which the strength of linear independence is increased is generated. Because the strength of the linear independence condition of the signal vector is increased, the speed of convergence of identification for a low-frequency disturbance element, such as a gravitational torque or a sliding-mode load torque, can be increased.

Abstract: An electrode for an electrochemical machining process is provided. The electrode includes an electrically conductive member defining at least one passage and an insulating coating partially covering a side surface of the electrically conductive member. The insulating coating does not cover at least one of first and second exposed sections of the electrically conductive member, where the first and second exposed sections are separated by approximately 180 degrees and extend substantially along a longitudinal axis of the electrically conductive member. The insulating coating also does not cover an exposed front end of the electrically conductive member. An electrochemical machining method is also provided, for forming a non-circular hole in a workpiece using the electrode.

Abstract: An electrochemical machining process for forming a non-circular hole from a substantially circular hole within a workpiece using an electrode. The electrode is made of an electrically conductive material and has insulated areas in which the electrically conductive material is coated with an insulating material, and exposed areas of metal or conductive material. The insulated areas and exposed areas extending in rows substantially along a longitudinal axis of the electrode. The electrode is first positioned in a substantially circular hole. An electric current is then applied to the electrode to electrochemically remove a predetermined amount of material from the substantially circular hole to form a non-circular hole. A variety of different non-circular shapes are achievable using the process.

Abstract: The invention concerns a method for the machining of a metallic structural component, particularly a structural component of a gas turbine, by means of finishing with a pulsed electrochemical ablation process, whereby the structural component features a pre-contour, to be finished, with different over-measures. The method is characterized by the following processing steps: a) determination of the different over-measures of the pre-contour, and b) bilateral and simultaneous finishing by means of a simultaneous feed of respectively at least one electrode disposed on different sides of the structural component, whereby the feed velocity of the electrode in the area of the largest over-measure of the pre-contour is higher than the feed velocity in the area of the smaller over-measure of the pre-contour.

Abstract: A method of electrochemical machining that includes the steps of: positioning a workpiece and a tooling piece in a first position; moving at least one of the workpiece and the tooling piece toward the other such that the workpiece and the tooling piece occupy a second position; moving at least one of the workpiece and the tooling piece away from the other such that the workpiece and the tooling piece occupy a third position; and during at least a portion of the moving of the workpiece and/or the tooling piece from the first position to the second position and from the second position to the third position, using a power supply to apply a voltage across a gap formed between the workpiece and the tooling piece.

Abstract: Disclosed herein is a method of manufacturing a hydrodynamic bearing in which a metal bearing made of sintered metal powder is internally subjected to chemical etching, to form hydrodynamic pressure grooves thereon, thus assuring a high-precision and reliable hydrodynamic bearing. The method includes: compressing metal powder that is a raw material of the bearing in a press unit, and sintering the compressed metal powder at a predetermined temperature, thus preparing a sintered bearing; removing foreign substances adhering to the sintered bearing through a deburring process, and pressing the sintered bearing into a desired shape; forming a hydrodynamic groove, configured to generate hydrodynamic pressure, on an internal surface of the shaped bearing using chemical etching; and conducting a post treatment of cleaning the bearing including the hydrodynamic grooves thereon and drying the bearing.

Abstract: An electrode and method for the electrochemical machining of a workpiece is disclosed. The electrode is designed as a cathodically polarized tool electrode. It has a geometry that corresponds to the geometry to be removed from the workpiece, at least in a machining range, and perviousnesses in the electrode to allow an electrolyte to flow through and exit at the electrode surface, at least in the area of the machining range. The perviousnesses are formed by a porous design of the electrode and/or by artificially created openings in the electrode or the electrode surface. The porosity distribution and/or the number, arrangement and configuration of the openings is selected such that a uniform electrolyte flow and/or electrolyte exchange at the electrode surface is ensured at least in the machining range of the electrode.

Abstract: An apparatus and method of electrochemical machining utilizes a computer controlled static array of electrically insulated cathode sections to selectively and individually energize the electrodes for the purpose of shaping the surface of a part. The tightly clustered array of electrodes can be formed by individual wires as an example. The waste reaction products may be managed so as to improve machining accuracy. The electrodes can be composed of materials capable of generating an oxide layer or that resist electrolytic dissolution to combat the problem of crossover erosion in closely spaced conditions. An alternative approach to remedy crossover erosion is to extend the reach of insulation into the gap space between tool and part.

Abstract: A machine for electrochemically polishing indentations within the wall of an aluminum workpiece, such as a wheel, has a cathode attached to an upper platen. The workpiece is mounted upon a lower platen which acts as an anode. Electrolyte is passed between the cathode and the anode while simultaneously a current is applied which passes through the cathode and the anode. The current is selectively pulsed to maximize polishing but at the same time to permit the flushing away of residual material and to cool the cathode and the workpiece.

Abstract: An electrode containing a dielectric layer on a surface of the electrode and an active zone containing a metal embedded below the surface of the electrode, wherein the electrode is configured to form a groove pattern on a workpiece by an electrochemical machining process is disclosed. The electrode is capable of manufacturing a workpiece such as a counter plate, a sleeve journal or a conical bearing containing a groove pattern for fluid dynamics bearing, the groove pattern having a pitch of less than 80 microns. The electrode could be made by a method including depositing a dielectric layer on a surface of a metal, depositing a photoresist layer on the dielectric layer, printing a groove pattern on the photoresist layer, etching or physico-chemically removing portions of the dielectric photoresist layers to form grooves in the dielectric layer; removing the photoresist layer; and filling the grooves with a metal to produce the electrode.

Abstract: Apparatus and process for removing surface regions of a component. The prior art involves removing surface regions of a metallic component by means of electrochemical processes. The electrochemical process is accelerated by the use of a current pulse generator.

Abstract: A method and an apparatus for electroerosive material machining of a workpiece with an elongated tool electrode are described. The tool electrode is guided in an electrode guide, in which an oval void is embodied. The wire segment located in the void is exposed to a magnetic field, as a result of which the wire segment can be deflected laterally. The lateral deflection is converted into an axial motion of the wire segment located in the region of the workpiece, in order to create an optimal work gap between the workpiece and the free end part of the wire segment.

Abstract: An electrode (10) is provided for electrochemical reduction of a workpiece (20) that is to be treated. The electrode (10) has a predefined contour and contains an electrically conductive material. The electrically conductive material of the predefined contour forms an electrode core (12). The outside of the electrode core (12) is covered with an insulation layer (13). The insulation layer (13) is porous and is made of an electrically non-conductive material.

Abstract: When forming metallic components, in particular three-dimensionally curved blades, which constitute a single piece with the blading of turbomachine rotor wheels, the linear oscillation of the electrode acting as a tool is superimposed by a circular oscillation, enabling the electrode to turn into the workpiece conformally with its shape. Further forming is performed by circular oscillation with circular feed in the one and/or the other direction. An embodiment of the corresponding apparatus comprises an electrode holder (9) with linear feed (Zvor) and linear oscillation (Zosz) and a workpiece holder (5) with circular oscillation (Cosz) and circular feed (Cvor).

Abstract: A lithographic printing plate substrate web is brush grained with some of the brushes having the bristles moving over the web along a first track and some additional brushes having the bristles moving over the web along a second track at an angle of at least 5° to the first track. Some of the brushes may have the axis of rotation perpendicular to the direction of movement of the web in the conventional manner and at least one additional brush having the axis of rotation at an angle to the direction of movement of the web. There may be a plurality of such additional brushes, usually two, with the additional brushes being angled with respect to each other. In one embodiment, the bristles of the additional brush track over the web in a direction perpendicular to the web movement. Subsequent to brush graining, the brush grained surface is electrochemically grained.

Abstract: An electrochemical machining process gives a workpiece such as a honeycomb panel a 3-dimensional profile form having a varying cross-section perpendicular to an axis of the profile form. In the process an electrode is maintained in a constant position relative to the axis and the surface of the profile form is exposed differentially to the action of the electrode in the axial direction to vary the amount of material removal and so vary the cross-section.

Abstract: According to this dynamic pressure groove processing method, dynamic pressure grooves are formed in specified regions by electrochemical machining with the electrode of an electrode tool put close to a workpiece in the initial stage. Through this electrochemical machining, corners of land portions adjacent to the dynamic pressure grooves can be curved and smoothed. Next, by subjecting the workpiece to electrochemical machining with the electrode of the electrode tool put away from the workpiece, the land portions are to undergo weak electrochemical machining. Surface roughness of surfaces of the land portions can be reduced, and the curved corners of the land portions can be made smoother at the same time. Therefore, the abrasion resistance characteristic of the dynamic pressure grooves can be improved further than that achieved by the conventional electrochemical machining, allowing the abrasion resistance characteristic and reliability to be sufficiently improved.

Abstract: A method for producing a separator in which a recessed gas path is formed. Depth fluctuations of the gas path can be reduced. The gas path having plural depths or gradation can be formed easily. An electrically conductive member 3, as a separator, and a processing electrode 16, having patterned electrode projections 20, are immersed in an electrolytic solution facing each other. Current is fed between member 3 and electrode 16 for electrolytic processing to dissolve the portion of the member 3 facing projections 20, thus forming a gas path 30 having a surface roughness Rz on this bottom surface 30e not larger than 1 &mgr;m.