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: A temperature estimation method estimating a temperature of a heat generating site in an oil-immersed electric appliance immersed in insulating oil, the insulating oil being silicone oil or ester oil. The temperature estimation method includes measuring concentrations of two types of thermal decomposition products in the insulating oil and calculating a temperature of the heat generating site in the oil-immersed electric appliance based on a concentration ratio between the two types of thermal decomposition products and a relational expression between the temperature of the heat generating site and the concentration ratio prepared in advance. When the silicone oil is adopted as the insulating oil, at least one of the two types of thermal decomposition products is straight-chain siloxane, alcohol containing silicon, or benzene. When the ester oil is adopted as the insulating oil, the two types of thermal decomposition products are fatty acids.

Abstract: The method for diagnosing the oil-filled electrical apparatus in the present invention is a method for diagnosing whether or not discharge has occurred inside the oil-filled electrical apparatus. The diagnosing method includes: an in-oil gases analyzing step of analyzing hydrogen gas and a gas selected from the group consisting of methane, ethane, ethylene, acetylene, hydrocarbon having a carbon number of 3 or 4, carbon monoxide, carbon dioxide, oxygen, and nitrogen, contained in an insulating oil used inside the oil-filled electrical apparatus; a step of analyzing a causative substance serving as a cause of generation of hydrogen in the insulating oil irrespective of whether or not the discharge has occurred; and a step of diagnosing whether or not the discharge has occurred based on an analysis result of the in-oil gases analyzing step and an analysis result of the step of analyzing the causative substance.

Abstract: A temperature estimation method estimating a temperature of a heat generating site in an oil-immersed electric appliance immersed in insulating oil, the insulating oil being silicone oil or ester oil. The temperature estimation method includes measuring concentrations of two types of thermal decomposition products in the insulating oil and calculating a temperature of the heat generating site in the oil-immersed electric appliance based on a concentration ratio between the two types of thermal decomposition products and a relational expression between the temperature of the heat generating site and the concentration ratio prepared in advance. When the silicone oil is adopted as the insulating oil, at least one of the two types of thermal decomposition products is straight-chain siloxane, alcohol containing silicon, or benzene. When the ester oil is adopted as the insulating oil, the two types of thermal decomposition products are fatty acids.

Abstract: A testing method of the present invention is a testing method for examining a degree of deterioration, due to oxygen, of an object material constituting an oil-filled electrical apparatus. The oil-filled electrical apparatus is an open-type oil-filled electrical apparatus including an insulating oil, an insulator, and a conductor, the insulating oil being contained as being in contact with the atmosphere. The object material is at least any of the insulating oil, the insulator, and the conductor. The testing method includes putting the insulating oil and the object material into a testing tank, keeping a state where dry air is continuously supplied to the upper space in the testing tank, and subsequently performing measurement of an index of deterioration of the object material due to oxygen.

Abstract: A stationary induction apparatus includes: an iron core with a shaft portion including a plurality of first electromagnetic steel plates stacked in a stacking direction, the shaft portion having a main surface located at each of both ends of the plurality of first electromagnetic steel plates in the stacking direction; a winding wound around the shaft portion; a first magnetic shield arranged along the main surface, the first magnetic shield being configured by stacking a plurality of second electromagnetic steel plates in a direction orthogonal to the stacking direction of the first electromagnetic steel plates; and a second magnetic shield arranged along the main surface, the second magnetic shield being arranged on each of both sides of the first magnetic shield, the second magnetic shield being configured by stacking a plurality of third electromagnetic steel plates in a direction orthogonal to the stacking direction of the second electromagnetic steel plates.

Abstract: A stationary induction apparatus includes: an iron core with a shaft portion including a plurality of first electromagnetic steel plates stacked in a stacking direction, the shaft portion having a main surface located at each of both ends of the plurality of first electromagnetic steel plates in the stacking direction; a winding wound around the shaft portion; a first magnetic shield arranged along the main surface, the first magnetic shield being configured by stacking a plurality of second electromagnetic steel plates in a direction orthogonal to the stacking direction of the first electromagnetic steel plates; and a second magnetic shield arranged along the main surface, the second magnetic shield being arranged on each of both sides of the first magnetic shield, the second magnetic shield being configured by stacking a plurality of third electromagnetic steel plates in a direction orthogonal to the stacking direction of the second electromagnetic steel plates.

Abstract: The method for diagnosing the oil-filled electrical apparatus in the present invention is a method for diagnosing whether or not discharge has occurred inside the oil-filled electrical apparatus. The diagnosing method includes: an in-oil gases analyzing step of analyzing hydrogen gas and a gas selected from the group consisting of methane, ethane, ethylene, acetylene, hydrocarbon having a carbon number of 3 or 4, carbon monoxide, carbon dioxide, oxygen, and nitrogen, contained in an insulating oil used inside the oil-filled electrical apparatus; a step of analyzing a causative substance serving as a cause of generation of hydrogen in the insulating oil irrespective of whether or not the discharge has occurred; and a step of diagnosing whether or not the discharge has occurred based on an analysis result of the in-oil gases analyzing step and an analysis result of the step of analyzing the causative substance.

Abstract: The conservator is provided with a housing that houses an insulation oil, a rubber bag that inflates or deflates inside the housing so as to contact an oil surface of the insulation oil, and an oil level gauge that detects the oil level of the insulation oil housed inside the housing. The oil level gauge includes a float member, an arm connected to one end of the float member, and a dial display unit that displays an oil level in response to an angle of the arm. The float member is swingably connected to the arm, extending away from the arm along the lower surface of the rubber bag. The length of the float member in the extending direction thereof is larger than the maximum thickness of the float member.

Abstract: The invention is related to a device for detecting insulation degradation in an inverter-driven load device, in particular a motor, the device including: zero-phase current measuring means for measuring a zero-phase current in power-feed lines, provided in the power-feed lines between an inverter device and the motor; and command control means for putting rotation of the motor on standby; wherein the zero-phase current measuring means measures the total of phase currents fed into respective phases so as not to rotate a shaft even when an external force is applied to the shaft during the rotation being on standby, whereby allowing regular detection of insulation degradation without switching over the power-feed lines connected with the load device.

Abstract: A diagnosis method for oil-filled electrical equipment, for diagnosing a risk of occurrence of an abnormality caused by generation of copper sulfide on insulating paper, wherein a step 1 of conducting sulfidation corrosion evaluation of insulating oil in the oil-filled electrical equipment is performed, any one of a step 2A-1 of analyzing the insulating oil for presence of dibenzyldisulfide and an oxidative degradation preventing agent, a step 2A-2 of analyzing the insulating oil for presence of a copper sulfide generation inhibitor, and a step 2B of checking presence of oxygen in an atmosphere of the insulating oil is performed, a step 3 of analyzing the insulating oil for presence of a byproduct derived when copper sulfide is generated from dibenzyldisulfide is performed, and a step 4 of diagnosing the risk of occurrence of an abnormality based on results of the steps 1, 2A-1, 2A-2, and 3 is performed.

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: The present invention is a diagnosing method for oil-filled electrical equipment for diagnosing a degree of risk with regard to occurrence of abnormality due to copper sulfide generation in oil-filled electrical equipment, and the method includes a first step of detecting specific compounds contained in insulating oil in said oil-filled electrical equipment, a second step of evaluating a possibility of copper sulfide generation at a dangerous part leading to dielectric breakdown in said oil-filled electrical equipment in accordance with a detection result obtained in said first step, and a third step of diagnosing a degree of risk with regard to occurrence of abnormality in said oil-filled electrical equipment in accordance with an evaluation result obtained in said second step. Said specific compounds include dibenzyldisulfide and 2,6-di-t-butyl-p-cresol.

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 method for manufacturing a thin metal wire electromagnetic shield includes the steps of preparing a thin metal wire bundle unified by bundling a plurality of thin metal wires each having a surface coated with an insulating material, and compression-molding the thin metal wire bundle by press working.

Abstract: In a stationary induction apparatus, an inter-partial-coil insulating plate and a plurality of inter-partial-coil spacer insulators form a refrigerant flow path in conjunction with each other. A space having an inter-partial-coil insulation dimension for withstanding an abnormal voltage is formed between a pair of partial coils. The inter-partial-coil insulating plate and the inter-partial-coil spacer insulators support both the pair of partial coils at an insulated state so as to maintain the inter-partial-coil insulation dimension. The insulators are arranged so as to be overlapped with each other in the direction in which mutually adjacent partial coils are opposed to each other.

Abstract: In a stationary induction apparatus, an inter-partial-coil insulating plate and a plurality of inter-partial-coil spacer insulators form a refrigerant flow path in conjunction with each other. A space having an inter-partial-coil insulation dimension for withstanding an abnormal voltage is formed between a pair of partial coils. The inter-partial-coil insulating plate and the inter-partial-coil spacer insulators support both the pair of partial coils at an insulated state so as to maintain the inter-partial-coil insulation dimension. The insulators are arranged so as to be overlapped with each other in the direction in which mutually adjacent partial coils are opposed to each other.

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: In a stationary induction apparatus, an inter-partial-coil insulating plate and a plurality of inter-partial-coil spacer insulators form a refrigerant flow path in conjunction with each other. A space having an inter-partial-coil insulation dimension for withstanding an abnormal voltage is formed between a pair of partial coils. The inter-partial-coil insulating plate and the inter-partial-coil spacer insulators support both the pair of partial coils at an insulated state so as to maintain the inter-partial-coil insulation dimension. The insulators are arranged so as to be overlapped with each other in the direction in which mutually adjacent partial coils are opposed to each other.

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.