Abstract: A plurality of magnetic shields are arranged to be aligned in an axial direction with a gap there between. Each of a plurality of magnetic shields is formed with a plurality of electromagnetic steel plates stacked in a direction vertical to each of the axial direction and a normal direction to a shield support surface. The shortest spacing distance between each of a plurality of magnetic shields and a support is twice or more the length of the gap between magnetic shields adjacent to each other in a plurality of magnetic shields.

Abstract: An impulse tester according to the present invention includes a first terminal, a second terminal, a voltage generation circuit, and an oscillation suppression circuit. The oscillation suppression circuit includes a discharge switch and a capacitor. The discharge switch has a first electrode and a second electrode. The first electrode is connected to the first terminal. The second electrode is disposed at a spacing from the first electrode. The discharge switch becomes conductive when a voltage difference between the first electrode and the second electrode is greater than a discharge voltage corresponding to the spacing between the first electrode and the second electrode. The capacitor is connected between the second electrode and the second terminal.

Abstract: A stationary induction apparatus includes a winding formed of a plurality of winding layers disposed in a central axis direction, an insulating barrier and an insulating oil. The insulating barrier includes a first extension extending radially outwardly of the winding and partitioning the outer peripheral ends, a second extension bent from an end of the first extension, extending toward one side in the central axis direction, and covering at least a part of one outer peripheral end of the outer peripheral ends, a third extension bent from an end of the second extension and extending radially outwardly of the winding, and a fourth extension bent from an end of the third extension, extending toward the other side in the central axis direction, and covering at least a part of the other outer peripheral end of the outer peripheral ends. The fourth extension faces the second extension with a spacing therebetween.

Abstract: An impulse tester according to the present invention includes a first terminal, a second terminal, a voltage generation circuit, and an oscillation suppression circuit. The oscillation suppression circuit includes a discharge switch and a capacitor. The discharge switch has a first electrode and a second electrode. The first electrode is connected to the first terminal. The second electrode is disposed at a spacing from the first electrode. The discharge switch becomes conductive when a voltage difference between the first electrode and the second electrode is greater than a discharge voltage corresponding to the spacing between the first electrode and the second electrode. The capacitor is connected between the second electrode and the second terminal.

Abstract: A partial discharge determination method and apparatus, and a partial discharge determination system capable of indicating how much margin is left before dielectric breakdown, in a lighting impulse withstand voltage test, and a power device for which whether partial discharge is caused is determined by them, and a method for manufacturing a power device including the partial discharge determination method. A low-pass filter receives an acoustic signal resulting from application of an impulse voltage and acquired by an acoustic emission sensor, and removes an electromagnetic noise superimposed on the acoustic signal. A mechanical oscillation removal unit removes a mechanical oscillation component of a device under test, from the acoustic signal resulting from application of the impulse voltage which is a high voltage, based on the mechanical oscillation component acquired in advance and included in the acoustic signal resulting from application of the impulse voltage which is a low voltage.

Abstract: A stationary induction apparatus includes a winding formed of a plurality of winding layers disposed in a central axis direction, an insulating barrier and an insulating oil. The insulating barrier includes a first extension extending radially outwardly of the winding and partitioning the outer peripheral ends, a second extension bent from an end of the first extension, extending toward one side in the central axis direction, and covering at least a part of one outer peripheral end of the outer peripheral ends, a third extension bent from an end of the second extension and extending radially outwardly of the winding, and a fourth extension bent from an end of the third extension, extending toward the other side in the central axis direction, and covering at least a part of the other outer peripheral end of the outer peripheral ends. The fourth extension faces the second extension with a spacing therebetween.

Abstract: A partial discharge determination method and apparatus, and a partial discharge determination system capable of indicating how much margin is left before dielectric breakdown, in a lighting impulse withstand voltage test, and a power device for which whether partial discharge is caused is determined by them, and a method for manufacturing a power device including the partial discharge determination method. A low-pass filter receives an acoustic signal resulting from application of an impulse voltage and acquired by an acoustic emission sensor, and removes an electromagnetic noise superimposed on the acoustic signal. A mechanical oscillation removal unit removes a mechanical oscillation component of a device under test, from the acoustic signal resulting from application of the impulse voltage which is a high voltage, based on the mechanical oscillation component acquired in advance and included in the acoustic signal resulting from application of the impulse voltage which is a low voltage.

Abstract: A static apparatus includes an iron core which includes a plurality of magnetic plates stacked in one direction and in which a shaft portion having a main surface and a side surface is formed, and a coil wound around the shaft portion. Slits extending in an axial direction of the shaft portion are formed in at least a surface layer magnetic plate constituting the main surface, of the plurality of magnetic plates. Some of the slits are formed in the main surface, at an end portion close to the side surface, at a predetermined formation density. The formation density of the slits is highest at the predetermined formation density, and is reduced as at least one of a minimum distance from the side surface within the main surface and a distance from the main surface on a side close to the slits in the stacking direction is increased.

Abstract: A transformer includes a leg iron core including a plurality of magnetic sheets stacked in one direction (Z axis direction), and a coil wound around the leg iron core. A slit is formed in at least a magnetic sheet which faces an inner peripheral surface of the coil in a stacking direction of the plurality of magnetic sheets, of the plurality of magnetic sheets. Since eddy current is divided by the slit, eddy current density can be reduced. By reducing the eddy current density, loss density in an iron core can be reduced. By reducing the loss density in the iron core, loss in the transformer can be reduced.

Abstract: A static apparatus includes an iron core which includes a plurality of magnetic plates stacked in one direction and in which a shaft portion having a main surface and a side surface is formed, and a coil wound around the shaft portion. Slits extending in an axial direction of the shaft portion are formed in at least a surface layer magnetic plate constituting the main surface, of the plurality of magnetic plates. Some of the slits are formed in the main surface, at an end portion close to the side surface, at a predetermined formation density. The formation density of the slits is highest at the predetermined formation density, and is reduced as at least one of a minimum distance from the side surface within the main surface and a distance from the main surface on a side close to the slits in the stacking direction is increased.

Abstract: A transformer includes a leg iron core including a plurality of magnetic sheets stacked in one direction (Z axis direction), and a coil wound around the leg iron core. A slit is formed in at least a magnetic sheet which faces an inner peripheral surface of the coil in a stacking direction of the plurality of magnetic sheets, of the plurality of magnetic sheets. Since eddy current is divided by the slit, eddy current density can be reduced. By reducing the eddy current density, loss density in an iron core can be reduced. By reducing the loss density in the iron core, loss in the transformer can be reduced.

Abstract: A power equipment includes a first internal abnormality detection apparatus comprising a first antenna accommodation pipe which is connected to a first connection pipe formed in a enclosed container and which accommodates a first antenna therein, and a first signal detection circuit which is connected to a first antenna and which detects an electromagnetic wave signal emitted when any abnormality has occurred within the enclosed container.

Abstract: A power equipment includes a first internal abnormality detection apparatus comprising a first antenna accommodation pipe which is connected to a first connection pipe formed in a enclosed container and which accommodates a first antenna therein, and a first signal detection circuit which is connected to a first antenna and which detects an electromagnetic wave signal emitted when any abnormality has occurred within the enclosed container.

Abstract: A method of cutting a material which includes a first step of cutting a material by laser beams emitted from a laser machine, and a second, subsequent step of cleaning a surface of the material cut by the first step wherein water is used as a solvent. The second step of cleaning may be performed by ejecting a jet of water or by moving a material impregnated with water along the surface of the material cut in the first step. The material impregnated with water may be a cloth, sponge or paper.