摘要:
This invention relates to an apparatus for controlling a D.C. power transmission system having a line-commutated converter which is connected between a first A.C. system and D.C. power transmission lines and which performs power conversion between A.C. power and D.C. power, and a forced-commutated converter which is connected between the D.C. power transmission lines and having a second A.C. system and which performs power conversion between A.C. power and D.C. power. In order to control transmission power in the two-terminal D.C. power transmission system wherein the two A.C. systems are associated by direct current, a control apparatus for a D.C. power transmission system according to this invention includes a voltage detector which detects a D.C. voltage of the D.C. power transmission lines, a first control circuit for comparing the output of the voltage detector with a voltage reference signal and for controlling ignition of the self-excited converter in accordance with the comparison, a detector which detects a current which is proportional to the conversion power of the line-commutated converter, and a second control circuit for comparing the output of the current detector with a power reference signal and for controlling ignition of the line-commutated converter in accordance with the comparison.
摘要:
A thyristor apparatus employing light-triggered thyristors comprises forward voltage detecting circuits (15) and a thyristor number detecting circuit (17). The forward voltage detecting circuits (15) detect forward voltages applied to light-triggered thyristors (13) to provide detected signals. The thyristor number detecting circuit (17) is responsive to the detected signals to cause light-triggered thyristors in a thyristor arm (U) to be turned on simultaneously in the case where the number of the light-triggered thyristors being supplied with forward voltages is one or more but not more than a predetermined number. Accordingly, if and when an overvoltage is applied to the thyristor arm (U), overvoltage suppressing elements (14) are prevented from being damaged even if partial commutation failure occurs in the light-triggered thyristors.
摘要:
A transmission line interconnecting system including an AC-DC converter connected to a first transmission line; and a forced-commutated type inverter connected to a second transmission line. DC terminals of the AC-DC converters and the forced commutated type inverter are connected and the output voltage of the forced commutated type inverter is varied by controlling DC voltage to feed a reactive power to the second transmission line in a normal state and to feed an active power from the first transmission line through the AC-DC converter and the forced excited type inverter to the second transmission line in an emergency state.
摘要:
A method for producing a raw material powder of a permanent magnet, includes: preparing a material powder of a permanent magnet, measuring magnetic characteristics of the material powder, and judging the quality of the material powder as the raw material powder based on a preliminarily determined relation between magnetic characteristics and the structure of the material powder. A method for producing a permanent magnet includes integrating material powders judged as good in the step of judging the quality as raw material powders by the method for producing a raw material powder of a permanent magnet. A method for inspecting a permanent magnet material powder includes transmitting a magnetic field to a material powder of a permanent magnet, receiving the magnetic field from the material powder, and measuring a magnetic field difference between the transmitted magnetic field and the received magnetic field as magnetic characteristics of the material powder.
摘要:
A rare earth magnet of the invention has a composition represented by the compositional formula RaHbFecCodBeMf, where: R is at least one rare earth element including Y; H is at least one heavy rare earth element from among Dy and Tb; M is at least one element from among Ga, Zn, Si, Al, Nb, Zr, Ni, Cu, Cr, Hf, Mo, P, C, Mg, and V; 13≦a≦20; 0≦b≦4; c=100−a−b−d−e−f; 0≦d≦30; 4≦e≦20; 0≦f≦3, and has a structure constituted by a main phase: a (RH)2(FeCo)14B phase, and a grain boundary phase: a (RH)(FeCo)4B4 phase and a RH phase, with a crystal grain size of the main phase of 10 nm to 200 nm.
摘要:
A semiconductor device is immersed into a cooling medium in its liquid phase disposed in a vessel. The cooling medium changes to its vapor phase due to heat from the semiconductor device to enter a condenser located above the vessel. The cooling medium condensed in the condenser passes through a conduit connected to the lower portion of the vessel to be directly mixed with the liquid cooling medium within the vessel.
摘要:
In a generating system including a plurality of parallel-operated fuel cells possessing a plurality of stacks, each of the cells is provided with a control circuit comprising chopper means each composed of switching elements which are ignition-controlled and each of which is connected to the output terminal of the respective cells, and ignition circuits each generating an ignition signal for ignition-controlling the switching elements in such manner that output current of the chopper means is made to be a prescribed value in accordance with the output current, whereby output control is effected in respect of each stack of the fuel cells so that load in respect of the respective cells is equalized and parallel operation with a high efficiency is effectuated.
摘要:
A rare earth magnet of the invention has a composition represented by the compositional formula RaHbFecCodBeMf, where: R is at least one rare earth element including Y; H is at least one heavy rare earth element from among Dy and Tb; M is at least one element from among Ga, Zn, Si, Al, Nb, Zr, Ni, Cu, Cr, Hf, Mo, P, C, Mg, and V; 13≦a≦20; 0≦b≦4; c=100−a−b−d−e−f; 0≦d≦30; 4≦e≦20; 0≦f≦3, and has a structure constituted by a main phase: a (RH)2(FeCo)14B phase, and a grain boundary phase: a (RH)(FeCo)4B4 phase and a RH phase, with a crystal grain size of the main phase of 10 nm to 200 nm.
摘要:
A connector comprises a plug and a socket. The plug has a main plug body, a plurality of contact pins projecting from the main plug body and including a contact pin for grounding, and a shielding member surrounding the plurality of contact pins. The socket has a main socket body, a plug receiving part provided on the main socket body for receiving the shielding member, a plurality of contact portions provided within the plug receiving part for making contact with corresponding ones of the plurality of contact pins and including a first contact portion for making contact with the contact pin for grounding, and a second contact portion provided on the main socket body for making contact with the shielding member. The plug is detachably coupled to the socket by inserting the shielding member into the plug receiving part. The first and second contact portions are made of a single contact member.
摘要:
The invention is a water purification system through denitrifying reduction with faculative anaerobes in which a nitrate harmful in the breeding of creatures such as tropical fishes and coral for appreciation and fishes and shellfishes for food and the like is decomposed and denitrifying-reduced in a short time. In this case, an aerobic circulating pathway of water reduced through a filter using aerobes is separately arranged from an anaerobic circulating pathway of water reduced through a closed type anaerobic filter device (10) using anaerobes. A nitrate produced in the aerobic circulating pathway is exuded into the anaerobic circulating pathway through powdery sand (5). This nitrate is decomposed in the anaerobic circulating pathway. A nitrogen gas inside the anaerobic circulating pathway produced in the decomposition of the nitrate is discharged at an isolated state so as not to contact with water in the aerobic circulating pathway.