Abstract: An insulated wire includes a conductor, a first insulation coating layer which is provided directly on the conductor and includes a polyamide-imide resin including dispersed inorganic fine particles, and a second insulation coating layer which is provided on the outer circumference of the first insulation coating layer and includes a polyamide-imide resin or a polyimide resin. A minimum winding multiplied diameter that does not cause a crack in the first insulation coating layer when the insulated wire is elongated by 30% by a method in compliance with JISC 3216 “5.1.1” and is wound around a winding bar is greater than 2d but smaller than 4d (where d is a conductor diameter of the insulated wire).

Abstract: A partial discharge measurement method includes: a moving step of moving an insulated wire including an insulating layer on a surface of the insulated wire; a voltage applying step of bringing an electrode which is connected to a power supply into contact with the insulating layer of the insulated wire which is moving, and applying a predetermined test voltage to the insulating layer while moving the insulated wire; a detection step of detecting, as a partial discharge signal, a signal which is more than or equal to a threshold value among signals involved in partial discharge events occurring from the insulating layer due to application of the predetermined test voltage; and a determination step of determining, based on a result in the detection step, frequency of occurrence of partial discharge events at the predetermined test voltage.

Abstract: An insulated wire includes a conductor, a first insulation coating layer which is provided directly on the conductor and includes a polyamide-imide resin including dispersed inorganic fine particles, and a second insulation coating layer which is provided on the outer circumference of the first insulation coating layer and includes a polyamide-imide resin or a polyimide resin. A minimum winding multiplied diameter that does not cause a crack in the first insulation coating layer when the insulated wire is elongated by 30% by a method in compliance with JISC 3216 “5.1.1” and is wound around a winding bar is greater than 2d but smaller than 4d (where d is a conductor diameter of the insulated wire).

Abstract: A partial discharge measurement method includes: a moving step of moving an insulated wire including an insulating layer on a surface of the insulated wire; a voltage applying step of bringing an electrode which is connected to a power supply into contact with the insulating layer of the insulated wire which is moving, and applying a predetermined test voltage to the insulating layer while moving the insulated wire; a detection step of detecting, as a partial discharge signal, a signal which is more than or equal to a threshold value among signals involved in partial discharge events occurring from the insulating layer due to application of the predetermined test voltage; and a determination step of determining, based on a result in the detection step, frequency of occurrence of partial discharge events at the predetermined test voltage.

Abstract: An insulated wire used under a condition where the insulated wire is brought into contact with ester-based synthetic oil includes a conductor and an insulating film on a periphery of the conductor. The insulating film is composed of an insulating paint including at least one resin component selected from polyamide imide, polyester imide, and polyimide and inorganic fine particles including alkali metal ion or alkaline-earth metal ion.

Abstract: The present invention provides a coil for a low-voltage inverter drive motor having insulation performance preventing the insulation breakdown even when partial discharge occurs within the warranty period of the motor. The coil is used for a low-voltage inverter drive motor that is driven at a low voltage of less than AC 700 V by an inverter power supply, the coil is formed of an insulated wire, and a total discharged charge amount discharged until an expiration of the warranty period is less than 10 C/mm2. The insulated wire is provided with a conductive wire and an insulation coating layer, the insulation coating layer being disposed covering the periphery of the conductive wire.

Abstract: A winding wire includes a conductor and a partial-discharge-resistant coating layer on the conductor. The partial-discharge-resistant coating layer contains a base resin, electrically insulating fine inorganic particles present in the base resin, and fine conductive particles present in the base resin in an amount of 1.25 to 3.00 parts by weight based on 100 parts by weight of the base resin.

Abstract: A insulated wire includes a conductor, and an insulating coating on a periphery of the conductor. The insulating coating includes an insulating film formed by applying and baking a polyester imide resin insulating coating material, and the insulating film has a relative permittivity of less than 3.5 both in a dried state and in a moisture-absorbed state. The insulating film is formed by applying and baking a polyester imide resin insulating coating material including an imide dicarboxylic acid and an alcohol component, the imide dicarboxylic acid being obtained by synthesizing a diamine component including aromatic diamine having not less than three aromatic rings and an acid component including aromatic tricarboxylic acid anhydride.

Abstract: An insulated wire includes a conductor, a partial-discharge-resistant layer formed on the conductor and including an insulating coating material including a base resin coating material and an inorganic fine particle dispersed in the base resin coating material, and an adhesion layer formed between the conductor and the partial-discharge-resistant layer and including an insulating coating material including the base resin coating material and an adhesion improver. A decrease rate in adhesion strength of the adhesion layer to the conductor after 20% elongation relative to that before the elongation is less than 25%.

Abstract: An insulated wire used under a condition where the insulated wire is brought into contact with ester-based synthetic oil includes a conductor and an insulating film on a periphery of the conductor. The insulating film is composed of an insulating paint including at least one resin component selected from polyamide imide, polyester imide, and polyimide and inorganic fine particles including alkali metal ion or alkaline-earth metal ion.

Abstract: An insulating varnish usable for an insulating coat of an insulated wire on a conductor with a quadrangular cross section contains polyamide-imide resin varnish and organosilica sol mixed with the polyamide-imide resin varnish. The polyamide-imide resin varnish contains solvent and polyamide-imide resin. The organosilica sol contains dispersion medium and silica particles dispersed in the dispersion medium. Cyclic ketones having boiling point in a range of 130 to 180° C. make up 70 to 100 wt % or more of the dispersion medium.

Abstract: An insulated wire including conductor, and a first resin layer formed on an outer periphery of the conductor, wherein the first resin layer includes an insulating resin including inorganic fine particles and an unreacted organic metal. An insulated wire including a conductor, a second resin layer formed on an outer periphery of the conductor and including an insulating resin that contains inorganic fine particles, and a third resin layer formed under the second resin layer and including an unreacted organic metal.

Abstract: An insulated wire includes a conductor, a partial-discharge-resistant layer formed on the conductor and including an insulating coating material including a base resin coating material and an inorganic fine particle dispersed in the base resin coating material, and an adhesion layer formed between the conductor and the partial-discharge-resistant layer and including an insulating coating material including the base resin coating material and an adhesion improver. A decrease rate in adhesion strength of the adhesion layer to the conductor after 20% elongation relative to that before the elongation is less than 25%.

Abstract: A insulated wire includes a conductor, and an insulating coating on a periphery of the conductor. The insulating coating includes an insulating film formed by applying and baking a polyester imide resin insulating coating material, and the insulating film has a relative permittivity of less than 3.5 both in a dried state and in a moisture-absorbed state. The insulating film is formed by applying and baking a polyester imide resin insulating coating material including an imide dicarboxylic acid and an alcohol component, the imide dicarboxylic acid being obtained by synthesizing a diamine component including aromatic diamine having not less than three aromatic rings and an acid component including aromatic tricarboxylic acid anhydride.

Abstract: An insulating varnish usable for an insulating coat of an insulated wire on a conductor with a quadrangular cross section contains polyamide-imide resin varnish and organosilica sol mixed with the polyamide-imide resin varnish. The polyamide-imide resin varnish contains solvent and polyamide-imide resin. The organosilica sol contains dispersion medium and silica particles dispersed in the dispersion medium. Cyclic ketones having boiling point in a range of 130 to 180° C. make up 70 to 100 wt % or more of the dispersion medium.