Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: The iron core characteristics of an amorphous iron core transformer degrade significantly when machining from material into a transformer. This phenomenon is suppressed to improve the iron core characteristics of the finished transformer products. In the present invention, an insulating thin film is formed in at least one side of an amorphous ribbon, and is formed in at least one for each plurality of amorphous ribbons of iron core material. Moreover, in the surface of the amorphous ribbon that is the iron core material of the amorphous iron core transformer, silane or the like is vapor deposited to form an insulating thin film, the insulating thin film being formed in the thickness of approximately 1 ?m. With such structure, an increase in eddy current loss occurring when machining from the material into a transformer is suppressed to reduce no-load loss of the transformer.

Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: There is provided a joint structure of a wound iron core in which iron core characteristics can be enhanced by improving the distribution of magnetic flux within an iron core. A wound iron core is formed to provide a joining structure or a butt joining structure and a lap joining structure disposed in an appropriate arrangement in which the a margin of overlapping is more increased as being closer to an outer periphery from an inner periphery of the iron core, taking a distribution of magnetic flux density within the iron core into consideration.

Abstract: The iron core characteristics of an amorphous iron core transformer degrade significantly when machining from material into a transformer. This phenomenon is suppressed to improve the iron core characteristics of the finished transformer products. In the present invention, an insulating thin film is formed in at least one side of an amorphous ribbon, and is formed in at least one for each plurality of amorphous ribbons of iron core material. Moreover, in the surface of the amorphous ribbon that is the iron core material of the amorphous iron core transformer, silane or the like is vapor deposited to form an insulating thin film, the insulating thin film being formed in the thickness of approximately 1 ?m. With such structure, an increase in eddy current loss occurring when machining from the material into a transformer is suppressed to reduce no-load loss of the transformer.

Abstract: There is provided a joint structure of a wound iron core in which iron core characteristics can be enhanced by improving the distribution of magnetic flux within an iron core. A wound iron core is formed to provide a joining structure or a butt joining structure and a lap joining structure disposed in an appropriate arrangement in which the a margin of overlapping is more increased as being closer to an outer periphery from an inner periphery of the iron core, taking a distribution of magnetic flux density within the iron core into consideration.

Abstract: There is provided a joint structure of a wound iron core in which iron core characteristics can be enhanced by improving the distribution of magnetic flux within an iron core. A wound iron core is formed to provide a joining structure or a butt joining structure and a lap joining structure disposed in an appropriate arrangement in which the a margin of overlapping is more increased as being closer to an outer periphery from an inner periphery of the iron core, taking a distribution of magnetic flux density within the iron core into consideration.

Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.

Abstract: There is provided a joint structure of a wound iron core in which iron core characteristics can be enhanced by improving the distribution of magnetic flux within an iron core. A wound iron core is formed to provide a joining structure or a butt joining structure and a lap joining structure disposed in an appropriate arrangement in which the a margin of overlapping is more increased as being closer to an outer periphery from an inner periphery of the iron core, taking a distribution of magnetic flux density within the iron core into consideration.

Abstract: A SF.sub.6 gas insulating electric apparatus usable as a circuit breaker, etc., containing a SF.sub.6 gas insulator and a resin insulator, both of which insulators are present in an atmosphere to be exposed to arcs, characterized by making at least the surface portion to be exposed to arcs of the resin insulator from a polymer containing nitrogen atoms or a polyolefin resin, and if necessary together with an inorganic filler powder, is excellent in both surface and inner arc resistance and can maintain breaking performance for a long period of time.

Abstract: There is disclosed a method of testing and verifying a performance for insulation to ground of a disconnecting switch when breaking a charging current. This disconnecting switch has a movable electrode and a fixed electrode which are arranged in a tank so as to face each other. One of these electrodes is connected to an electrostatic capacity load and the other is connected to a power supply. This test method comprises the steps of: applying a voltage from the power supply through the disconnecting switch to the load to cause the voltage to be trapped in the load; and applying a voltage of the polarity opposite to that of the trapped charged voltage from the power supply to the disconnecting switch to cause the discharge between those electrodes, thereby verifying the performance for insulation to ground.

Abstract: In a puffer type gas circuit breaker comprising at least a pair of main movable and fixed contacts, a puffer device and a pair of preinsertion resistor contacts inserted electrically in parallel with the main movable and fixed contacts, the preinsertion resistor contacts are closed prior to the closing of the main movable and fixed contacts, and are separated a short time after the main movable and fixed contacts have been closed.