Abstract: An abnormality detecting apparatus in which noise is rejected in determining the condition of each of rotating electrical machines, so that a partial discharge of a rotating electric machine is detected with high accuracy. The abnormality detecting apparatus includes partial discharge detectors for detecting a partial discharge of a rotating electrical machine, a switching unit for selecting a partial discharge detector, a partial discharge measurement section for measuring the signal from the selected switch, a computer for selecting the respective partial discharge detectors or sequentially selecting respective partial discharge detectors for measurement, noise rejection, insulation diagnosis judgement, and data management for the respective discharge detectors, and for displaying measurement results, and a control section for controlling the switching unit and the partial discharge measurement section through the computer.

Abstract: A stator coil for a rotating electrical machine having a ground wall insulation of a stator coil impregnated with a resin, maintaining a releasing characteristic between the ground wall insulation and a slot of a stator core, preventing surface corona and exhibiting excellent characteristics for a long time. The stator coil of the rotating electrical machine has a conductor covered with an insulating layer and a surface-corona preventive layer, the stator coil being accommodated in the slot of a stator core and, together with the stator core, impregnated with a thermosetting resin so that the stator coil is integrated with the stator core. The surface-corona preventive layer has a wound semiconductive tape and a composite tape including a fluorine-containing non-bonding material layer on a second semiconductive tape.

Abstract: The present invention provides a wire saw for use in cutting works of electronics materials or optical materials and a method for manufacturing the same, said wire saw having the following characteristic features. Namely, onto a high-strength core wire 2, abrasive grains 3 having a grain size not smaller than two-thirds the thickness of a layer of resin bond 4 on said core wire 2 but not exceeding a half the diameter of said core wire are fixed with said resin bond, said resin bond containing a filler having a grain size smaller than two-thirds the thickness of said resin bond layer. The thus structured and arranged wire saw has an improved efficiency and precision in cutting. The wire saw can be manufactured readily by using an enamelling oven.

Abstract: A synthetic single crystal diamond for wire drawing die; the process of manufacturing it and a wire drawing die to utilize it are disclosed. At least one plane of the diamond for wire drawing die is a cleavage plane of (111) faces, and the drawing hole of wire drawing die lies vertical to the cleavage plane.The diamond for the wire drawing die is produced by providing a synthetic single crystal having 20-400 ppm nitrogen of Ib type diamond. A groove is made on the diamond surface parallel to (111) faces employing energy beams such as a laser beam, an ion beam and an electron beam. A wedge is struck into the groove to cleave the diamond, and a plate is obtained. Furthermore, the plate is divided into polyhedrons, employing either an energy beam or a blade. The cleavage plane of the polyhedron is almost parallel to the (111) faces of crystal, therefore the cleavage plane is used as the standard plane to build the drawing hole.

Abstract: A blade comprises a disc-shaped substrate having a major surface and an outer peripheral edge portion encircling the major surface, and an abrasive grain layer mounted on the outer peripheral edge portion of the substrate. The substrate includes a first disc having a major surface, and a second disc having a major surface which is superposed on that of the first disc. The major surface of the second disc is separated from that of the first disc, thereby defining a clearance between the major surfaces of the first and second discs and correspondingly forming a convex surface region on the outside surface of the substrate. The peripheral portion of the convex surface region is provided with a contact portion where the major surfaces of the first and second discs are slidably in contact with each other.

Abstract: A synthetic single crystal diamond for wire drawing die; the process of manufacturing it and a wire drawing die to utilize it are disclosed. At least one plane of the diamond for wire drawing die is a cleavage plane of (111) faces, and the drawing hole of wire drawing die lies vertical to the cleavage plane. The diamond for the wire drawing die is produced by providing a synthetic single crystal having 20-400 ppm nitrogen of Ib type diamond. A groove is made on the diamond surface parallel to (111) faces employing energy beams such as a laser beam, an ion beam and an electron beam. A wedge is struck into the groove to cleave the diamond, and a plate is obtained. Furthermore, the plate is divided into polyhedrons, employing either an energy beam or a blade. The cleavage plane of the polyhedron is almost parallel to the (111) faces of crystal, therefore the cleavage plane is used as the standard plane to build the drawing hole.

Abstract: A diamond tool, e.g., cutting tool, dresser, wire drawing die, etc., having excellent wear resistance, heat resistance and oxidation resistance and with an improved tool life is provided, which is mainly composed of a synthetic diamond single crystal containing boron or boron and nitrogen.

Abstract: A tool comprising a blank and shank, bonded at a low temperature through a bonding layer of gold formed by thermocompression bonding between the blank and shank is provided which can be used at a high temperature independently of the temperature at which the blank and shank were bonded.

Abstract: A method for bonding a cubic boron nitride sintered compact to other cubic boron nitride sintered compact or to a body of shank material is disclosed. The method comprises forming a Ti layer of 0.01-1 .mu.m in thickness over a bonding interface between two cubic boron nitride sintered compacts or between a cubic boron nitride sintered compact and a body of shank material, forming a layer of Ni or Cu over the Ti layer to a thickness of 0.01-5 .mu.n, putting together the two cubic boron nitride sintered compacts or the cubic boron nitride sintered compact and the body of shank material with a 10-1,000 .mu.m foil of Al, Al-Ni alloy or Ag--Cu--In alloy being placed over the boding interface, and heating the cubic boron nitride sintered compact structure to temperatures above the meeting point of the metal foil and not exceeding 750.degree. C. in an inert atmosphere or in a vacuum.