Abstract: A direct-current circuit includes: a breaker that is inserted into the direct-current line and becomes a path for direct current when in a steady state; a resonance circuit connected in parallel with the breaker and superimposing resonance current on the direct current; and a first disconnector and a second disconnector connected to first and second connection points of the breaker and the resonance circuit, respectively, and forming a path for the direct current together with the breaker. The resonance circuit includes a series circuit that includes a capacitor and a reactor and generates the resonance current, a charging resistor for charging the capacitor with a direct-current potential of the direct-current line, a high-speed switch connected in series with the series circuit on the capacitor side and superimposing the resonance current on the direct current, and an arrester connected in parallel with the capacitor and the high-speed switch.

Abstract: A direct current circuit breaker used in a self-commutated direct current power transmission system includes a high-speed circuit breaker and a low-speed circuit breaker connected in series. The high-speed circuit breaker includes a high-speed circuit breaker interruption unit to interrupt a DC current flowing through a direct current line when a fault has occurred, and a current limiting element connected in parallel therewith. The low-speed circuit breaker includes a low-speed circuit breaker interruption unit to interrupt a DC current when a fault has occurred. A time required for the high-speed circuit breaker interruption unit to interrupt the DC current is shorter than a time required for the low-speed circuit breaker interruption unit. The low-speed circuit breaker interruption unit completes interruption of the DC current before a voltage applied to the current limiting element becomes lower than a minimum voltage allowable for the system.

Abstract: A wind power generation system according to the present invention includes: a DC bus; a plurality of feeders connected to the DC bus for transmitting DC powers to the DC bus; a plurality of wind power generators; a plurality of AC/DC converters connected one by one to each of the wind power generators for converting AC powers generated by the connected wind power generators, into DC powers, and outputting the DC powers to the feeders; and a DC breaker and a diode, which serve as a current limiting unit installed on each of the feeders for preventing a DC current from flowing from the DC bus into the feeder.

Abstract: A wind power generation system according to the present invention includes: a DC bus; a plurality of feeders connected to the DC bus for transmitting DC powers to the DC bus; a plurality of wind power generators; a plurality of AC/DC converters connected one by one to each of the wind power generators for converting AC powers generated by the connected wind power generators, into DC powers, and outputting the DC powers to the feeders; and a DC breaker and a diode, which serve as a current limiting unit installed on each of the feeders for preventing a DC current from flowing from the DC bus into the feeder.

Abstract: An AC circuit breaker is provided between an AC system and an AC-DC converter, and a DC circuit breaker is provided between a DC line and the AC-DC converter. A bypass switch capable of short-circuiting a converter cell included in the AC-DC converter is connected to the AC-DC converter. At the time of a fault in the DC line, the bypass switch is turned on to interrupt the supply of DC power from the AC system to the DC line.

Abstract: A direct-current circuit includes: a breaker that is inserted into the direct-current line and becomes a path for direct current when in a steady state; a resonance circuit connected in parallel with the breaker and superimposing resonance current on the direct current; and a first disconnector and a second disconnector connected to first and second connection points of the breaker and the resonance circuit, respectively, and forming a path for the direct current together with the breaker. The resonance circuit includes a series circuit that includes a capacitor and a reactor and generates the resonance current, a charging resistor for charging the capacitor with a direct-current potential of the direct-current line, a high-speed switch connected in series with the series circuit on the capacitor side and superimposing the resonance current on the direct current, and an arrester connected in parallel with the capacitor and the high-speed switch.

Abstract: A traction motor comprises a stator, a rotor core, an iron core holder, a cooling fan, a rotor, a frame, a bracket, and a bearing unit. The cooling fan includes a main plate that separates the inside and the outside of the totally-enclosed traction motor; blades provided on the bracket side of the cooling fan and along a rotational direction of the rotor; and a guide provided on the bracket side of the blades. In the bracket, inlets are provided within an area obtained when the guide is projected onto the bracket. The guide is formed such that air drawn in through the inlets is guided to a rotor shaft.

Abstract: A direct-current circuit breaker includes a switching unit inserted in the direct-current line; and a commutation circuit that includes a series circuit including a first current-limiting element and an interrupting unit that forms a current zero point by superimposing a resonance current on a direct current flowing in the direct-current line and interrupts the direct current at the current zero point, that is connected in parallel with the switching unit, and that becomes a flow path for the direct current after the switching unit is opened, wherein current interruption is performed by the interrupting unit after the switching unit is opened.

Abstract: A direct-current circuit breaker includes a switching unit inserted in the direct-current line; and a commutation circuit that includes a series circuit including a first current-limiting element and an interrupting unit that forms a current zero point by superimposing a resonance current on a direct current flowing in the direct-current line and interrupts the direct current at the current zero point, that is connected in parallel with the switching unit, and that becomes a flow path for the direct current after the switching unit is opened, wherein current interruption is performed by the interrupting unit after the switching unit is opened.

Abstract: A novel electromagnetic balance-type weighing apparatus according to the invention includes a weighing pan/balance beam assembly (15) whose balance beam is angularly displaced as a function of the weight of an object of weighing placed on the weighing pan. An electromagnetic coil (9) is provided to generate an electromagnetic force that offsets the displacement of the balance beam of the weighing pan/balance beam assembly (15) caused by the weight of the object of weighing. A displacement detector (3, 4, 5) is provided to detect the displacement of the balance beam of the weighing pan/balance beam assembly (15). An operation unit (7) performs operations to determine a control voltage in response to the detection signal transmitted from the displacement detector (3, 4, 5). A current transducer circuit (20) generates an electric current in response to the control voltage applied to it by the operation unit (7) and supplies it to the electromagnetic coil (9).

Abstract: An inverter controlled conveying/measuring apparatus according to the invention includes a conveyor (3) for conveying an object (W) of measurement. The conveyor (3) is driven by an AC motor (M2). Inverter (20) controls and operates the conveyor (3) at a given speed by supplying the AC motor (M2) with frequency converting signals according to a specified frequency. A measuring section (4) is arranged on a conveying path of the conveyor (3) in order to measure an attribute of the object (W) being conveyed by the conveyor (3).

Abstract: A conveying section is engaged with works to be weighed to sequentially convey the works at predetermined intervals along a substantially arcuated path. An engagement releasing section sequentially releases engagement between the conveying section and one of the works at a predetermined region substantially equal to one of the predetermined intervals of convey midway along the arcuated path of the conveying section. A conveyor section is linearly arranged to oppose the predetermined region on the arcuated path on which engagement between the conveying section and the one of the works is released by the engagement releasing section. The conveyor section linearly and sequentially conveys the one of the works released from the conveying section. A weighing section sequentially measures weight of the one of the works while the one the works released from the conveying section is linearly conveyed by the conveyor section.

Abstract: The disclosed pump includes a casing housing a working chamber and an impeller. The impeller includes a blade wheel mounted on a rotational shaft, a plurality of pumping blades extending axially from the periphery of the blade wheel and a cover mounted within the casing and fitted over the blade wheel for rotation therewith. The cover includes an end face member defining one side of the working chamber and a cylindrical skirt portion depending from the periphery of the end face member and encircling the blade wheel and defining a hollow interior space within the impeller between the end face member and the blade wheel. The end face member has a plurality of slots through which the blades extend into the working chamber. The interior surface of the cover defines a plurality of pockets, each contoured to receive and mate with one of the blades so that in use each blade rests flush against one surface of the pocket with no space for fluid therebetween.

Abstract: An improved liquid fuel combustion apparatus of the type including a cylindrical combustion chamber, an ignition plug, an ignition plug mounting sleeve and a heat exchanger is disclosed. The cylindrical combustion chamber and the heat exchanger constituting essential components of the apparatus are separable. The ignition plug mounting sleeve is firmly mounted within coaxially aligned nipples on the heat exchanger and on the combustion chamber so that its inner wall lined with a layer of wick is exposed to the interior of the cylindrical combustion chamber. Typically, the ignition plug mounting sleeve is secured to the mounting seat by securing a flange on the outer surface of the mounting sleeve to mounting seat associated with the nipple of the heat exchanger by means of bolts with a packing interposed therebetween.

Abstract: An apparatus for carrying and separating articles includes a pair of parallel endless belts made of an elastic material, a plurality of carrying rods bridging the two belts in the transversal direction and carriers each engaged with adjacent carrying rods and capable of sliding relative thereto in transversal directions. Articles are put on the carriers and are separated with displacement of the carriers in transversal directions. The belt has a core buried in it and incapable of elongation or contraction in the length direction. The pair of belts have carrying rod mounting pins projecting from their opposed edges. These pins are coincident with the center of the cores. They each have an engaged portion and an embedded portion, the engaged portion being engaged in an end of a carrying rod, the embedded portion being embedded in a belt.

Abstract: An improved vaporized liquid fuel combustion apparatus of the type including a cylindrical combustion chamber, a blower, and end plate located between the combustion chamber and the blower and a heat exchanger for heating air by utilizing thermal energy generated in the combustion chamber is disclosed. The combustion chamber, the blower, the end plate and the heat exchanger are separable components and the blower and the heat exchanger are firmly assembled together by tightening bolts at a single flange connection with the end of the combustion chamber making gastight contact with the peripheral end part of the end plate. The one end part of the combustion chamber, the peripheral end part of the end plate are formed and the one end part of the heat exchanger are formed to mate together.

Abstract: An improved apparatus for heating fluid by burning liquid fuel is disclosed. To heat fluid such as water, air or the like medium heat exchanging is effected between the combustion chamber in which liquid fuel is burnt with combustion air introduced therein and the fluid passage through which fluid to be heated flows. The apparatus includes means for controlling rotational speed of a single motor for rotating the fuel pump and the blower, means for controlling a flow rate of fuel to be pumped from the fuel pump, means for controlling a flow rate of combustion air and an electronic control unit into which a variety of parameters relative to the above-mentioned means are inputted. The parameters are processed in the electronic control unit to individually control the means for controlling rotational speed of the motor, the means for controlling a flow rate of fuel and the means for controlling a flow rate of combustion whereby heat exchanging therebetween is achieved without fluctuation in temperature of fluid.

Abstract: A compound carburetor wherein, in order that, in the course of the transit from the primary side to the secondary side, an air-fuel mixture fed to each cylinder may maintain a uniform air-fuel ratio without causing an air lock and the transit may be made smoothly and definitely, an independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes in the course a pipe connected between a carburetor part and manifold part.

Abstract: A construction of an inner venturi constituted by pressingly inserting an inner core having a main nozzle into an outer core having a main fuel passage such that a main fuel passage and the main nozzle open to each other, forming an annular fuel well between the outer wall of said inner core and the inner wall of said outer core, and arranging an appropriate number of bleed air inlet holes for admitting air into said fuel well and an appropriate number of sub-nozzles on the circumference of said inner core for delivering fuel from the fuel well.

Abstract: A carburetor provided with a rocking member which will be able to forcibly move a needle valve to a valve closing position through a float when a carburetor body inclines by an angle larger than a predetermined angle from a normal position, in order to prevent the overflow of a fuel caused by continuously flowing into the float chamber from a fuel tank when the carburetor body inclines extremely.