Showing papers by "Mitsubishi Electric published in 1973"

Characteristics of superconductive magnetic suspension and propulsion for high-speed trains

Abstract: Theoretical analyses are carried out on a magnetic suspension and a linear synchronous motor, both utilizing superconducting magnets. The derived theory is applied to the studies of the high-speed train models. In the suspension system investigated here, the roadbed is equipped with normal conducting coils. The magnetic lift force is found to be pulsating, and a design criterion for eliminating the pulsation components in the lift force is derived. An improved suspension system is proposed, which consists of a "ladder-type conductor" in the roadbed. This new system is investigated theoretically. An end effect of the suspension system is also studied. In the linear synchronous motor, the methods of minimizing reaction forces are derived. The combined magnetic suspension and propulsion system is analyzed. It is found that the influence of the track loops for the suspension on the linear synchronous motor is not very significant.

Instability of feedback systems by orthogonal decomposition of L 2

Abstract: A useful method for investigating the L 2 instability of the feedback interconnection of a linear unstable subsystem G and a nonlinear stable subsystem N is to resolve L 2 into two orthogonal spaces on the basis of the input-output behavior of G . This yields insight and permits simple proofs of various instability counterparts to stability theorems.

End-Effect of High-Speed Linear Induction Motor

Abstract: This paper presents a new theory of the end-effect of a high-speed linear induction motor, an experimental proof of the theory, and several countermeasures to eliminate the end-effect. The theory is developed on the basis of a two-dimensional solution of electrodynamic equations and compared with the experimental results. The experiment has been made by use of a rotary type test facility; the maximum test velocity is 450 km/h. It is found that the theory agrees well with the experiment and that the end-effect exercises a very adverse influence on motor performance. The end-effect is investigated as functions of design parameters by making use of the theory. Some measures to counter the end-effect are proposed and discussed. A parallel-connected linear induction motor is also proposed as a measure to compensate the end-effect, and its performance is studied.

Apparatus for charging materials into vertical heating furnace

Abstract: In the vertical heating furnace of the bottom charge type having a lift to go up for charging a piece of to be-heated material, an apparatus for charging a piece of such material into the furnace, provided, for free vertical movement, with a cap for supporting the so charged piece of material by the engagement of the groove made on the bottom surface thereof with the tip of said piece of material.

Design Considerations on the P. P. F. for a Control Center

Abstract: Permanent Power Fuse which is called by the abbreviated name P. P. F. is an entirely new reusable fuse with excellent current limiting performance developed by Mitsubishi Electric Corp. of Japan1. Since our previous work on the development of the series of the low voltage P. P. F. up to 800 A1 ., various P. P. Fused devices have been applied to the actual field. Among these applications, the application of the P. P. F. to a control center is an example which makes the very best use of the self-recovering function of the P. P. F. This paper explains the design considerations on the P. P. F. for use in a control center. In the considerations, emphases are put on quantitative discussions on the stable performance for repeated operation and the recovery time.

A theory of formal microprograms

Abstract: This paper attempts to formulate a mathematical theory of microprogramming, along with Glushkov's approach on formal microprogram transformations In particular, we have attempted to construct an algebraic theory of formal microprograms

Relation between electrical and optical gaps of amorphous semiconductors in the SiAsTe system

Abstract: Electrical and optical properties of semiconducting SiAsTe glasses have been investigated. Compositional dependences of the properties in the SixAsyTez system are examined as a function of atomic percentage x (or y, z) of one element with parameters of constant atomic ratio y/z (or x/z, x/y) of the other two elements. A pre-exponential factor σ0 in the dc conductivity formula is estimated to be (2.1 ± 0.6) × 10 4 (Ω · cm ) −1 , inependently of the compositions. A systematic relationship between the compositional changes in the electrical gap Eg(el) and optical gap Eg(op) has been found. The energy gaps increase linearly with increasing Si content and decreasing Te content, but are almost independent of As content. The relation between Eg(el) and Eg(op) is expressed by Eg(el) = 1.60 Eg(op) − 0.15 in eV. On the other hand, the optical absorption coefficient α(Ω) near the band edge follows the empirical formula, α(Ω) = α 0 exp ( h Ω/E s ). The experimentally determined factor Es increases linearly with Eg(op) and is closely related to the energy difference between the two gaps. A tentative model to explain these experimental results is proposed by taking into account of the effect of the potential fluctuations in such disordered materials.

Electrical Characteristics of High-Voltage High-Power Fast-Switching Reverse-Conducting Thyristor and Its Applications for Chopper Use

Abstract: The structures, features, electrical characteristics, and successful application results of two types of high-voltage high-power reverse-conducting thyristors are described. The first has blocking voltage ratings of 1300 V and current ratings of 400 A in the forward direction and 150 A in the reverse direction, with a turn-off time of 30 ?s. The second has ratings of blocking voltage of 2500 V, current ratings of 400 A in the forward direction and 150 A in the reverse direction, with a turn-off time of 40?s.

Development of new mica paper epoxy insulation systems for high voltage rotating machines

Abstract: Better insulation performance is persistently required for high voltage rotating machines with the trend of increasing capacity and rated voltage Resistance to thermal shock, mechanical reliability and dielectric strength of insulation are especially important As for the impregnating varnish, asphaltic compound has been replaced by synthetic resins with progress in the chemical industry Unsaturated polyester and epoxy resins are the most popular resins, the latter becoming more important because of their overall suitability On the other hand, the main barrier insulating material tends to move toward reconstituted mica from mica splittings In this paper, electrical and therm omechanical performances of newly developed epoxy insulation systems based on mica splittings and reconstituted mica are compared with asphaltic compound and unsaturated polyester insulation systems based on mica splittings by extensive thermal cycle tests Superior characteristics of epoxy insulation systems are proved

System for controlling rolling mills

Abstract: There is described a system for controlling the tensile force acting on a rolling material between individual sets of rollers of a continuous rolling mill. In order to carry out the continuous rolling operation with accuracy, the constants of transfer function of the tensionfree control loop is automatically corrected in accordance with variations in the rolling conditions such as dimension and shape of the steel material being worked, the rolling speed, the distance between individual sets of rollers and the like. Furthermore, the control includes a learning function.

Development of 500KV Gas Insulated Switchgear and its Application

Abstract: The application of Gas Insulated Switchgear (GIS) up to 275kV substations has been proven and the authors have been working jointly on the research and development, with a view of supplying GIS for the 500kV trunk systems in the near future. To demonstrate the reliability and intearity of GIS. a prototype installation was provided and subjected to excess voltage and current during endurance and service tests. The satisfactory results obtained have led to the Kansai Electric Power Co. (KEP CO) Japan placing orders for a 500 kV substation to be commissioned in March 1973. The paper covers some specific engineering problems encountered on 500kV GIS, the results of tests and the investigations of its application.

Channeling Analysis and Electrical Behavior of Boron Implanted Silicon

Abstract: The depth distribution and the lattice location of boron atoms and their correlations with defects and effective carriers in heavily boron implanted silicon have been studied by means of channeling analysis and electrical measurements with a successive layer removal technique. The same set of crystals was used, which had been implanted with boron ions of 100 keV to doses of 1 x 1016/cm2 at room temperature. The 11B(p,α)8 Be reaction was utilized to obtain the boron distribution and to determine the lattice location of boron atoms. The angular dependences of the yields of the (p,α) reaction around the , and axes were measured after annealing at 900°C with non-etched, 2950 A etched, and 3750 A etched samples. Main results obtained are the following: 1) Boron atoms which exceed the solubility limit, precipitate parallel to the direction in the region of the highest concentration of boron atoms after annealing at 700-900°C. This is also confirmed by the facts that the distribution of the secondary defects coincides with that of boron and that the percentage of the electrically active boron is significantly lower around the boron ion range. 2) The boron distribution does not change significantly after annealing up to 900°C. A considerable diffusion of boron atoms was detected after annealing at 1000°C. In the temperature range from 900°C to 1000°C, the precipitated boron atoms are released and diffuse to become electrically active. 3) The depth distribution of boron atoms deviates from a gaussian. The projected ion range is approximately 20% shorter than the value calculated from the LSS theory.

Ionic conduction mechanism of polymers

Abstract: Many polymers have excellent electrical properties, as well as a variety of physical, chemical, and mechanical properties, that make them very suitable for insulating materials. Since knowledge of the nature of electrical conduction in insulating materials is incomplete, it is sometimes not clear whether the charge transfer process involves the transport of ions or electrons for a certain polymer. However, it would appear that the electrical conduction of polar polymers in a relatively low electric field is ionic. It is, therefore, useful to try to explain some of the complexities of the conduction process in polymers on the basis of behavior of ionic charge carriers. The complexities noticed commonly are the abrupt change in conductivity versus temperature behavior at the glass transition temperature of polymers and the derivation from Arrhenius behavior at temperatures above the glass transition temperature.

The application of gas plasma to the fabrication of MOS-LSI

Abstract: The gas plasma technique was applied to the etching of Si 3 N 4 , poly-Si, SiO 2 and the multi-layer films in fabrication of MOS-LSI. For Si 3 N 4 film in the selective oxidation process, the so-called side-etching can be controlled from negative, zero to positive, by varying the plasma conditions. The Al-gate MOS-LSI's fabricated by this process work well and havegood reliability, and their wafer yield was better than that of devices fabricated by the process using the wet-chemical etching. The gas plasma technique could give the tapered etching of poly-Si film in the Si-gate process and also smooth edges without under-cutting in the multi-layer structures including the MNOS and SNOS. SiO 2 films could be etched successfully by the gas plasma technique, but the processing time may be too long depending on processes.

An Injection Type Electro-Luminescence in ZnSe-Sno2 Hetero-Junction

Abstract: Injection type electro-luminescence has been observed in the forward biased ZnSe-SnO2 heterostructure junction. The junction shows good rectification characteristics. Clearly separated four main emission bands are found at energies of 2.00, 2.35, 2.70 and 2.80 eV at 90 K. Emission light intensity has almost no frequency dependence from DC up to 10 KHz. Injection current and temperature dependence of the emission spectra are demonstrated. The C-V characteristic and the spectral response of photovoltaic effects are also measured to determine the potential profile of the junction.

Fundamental aspects of a new electrodeposition insulating process "MEDIS"

Abstract: Within the past ten years, electrodeposition coating for general protective purposes has been extended into a wide range of industries because of its high efficiency and the potential advantage of using water based materials1.

Effect of Deuteron Irradiation on the Magnetic Anisotropy of Thin Ni-Fe Films

Abstract: Thin films of Ni-Fe (Ni 50–100%) are irradiated by 250 kV-deuterons below 50°C. The anisotropy constant, Ku, of normal incidence films reaches a saturation value with 10–20 minutes irradiation (1016 deuterons/cm2), easy axis being parallel to the magnetic field applied during irradiation. The saturation value of Ku as a function of Ni concentration is explained well by the atom and vacancy orders. The change in Ku of oblique incidence films is independent of the field direction during irradiation. In the case of 30° incidence, Ku increases (Ni 90%) at the initial stage of irradiation, and after the initial change |Ku| decreases monotonously. In the case of 60° incidence, a similar result is obtained except that the initial stage change in Ku with irradiation is not so clear. These results are suspected to be due to a change in the columnar structure caused by the vacancy migration.

Thermal Runaway Phenomena of Composite Superconductors

Abstract: A theoretical and experimental investigation on thermal runaway phenomena of composite superconductors has been performed. It has been theoretically found that there are two substrate limited currents, a “thermal runaway current” Ih and a “completely stable current” Is, in addition to the take-off current and the recovery current. For a current above Ih the temperature of a composite conductor rises rapidly, and for a current below Is the conductor always recovers to superconducting state no matter how large a disturbance has occurred. The thermal runaway phenomena can be explained by considering the temperature dependences the resistivity of the substrate and heat transfer rate to liquid helium.The cornposite comductor tested consists of a copper strip 0.86mm thick by 2.16mm wide on which a copper-clad Ti-Nb-Ta superconducting wire of 0.37mm diameter (core dia.: 0.25mm) is soldered. The test results for the thermal runaway currents agreed well with the predicted. For example, the conductor in an external magnetic field of 43kOe began to runaway thermally at Ih=360A when the temperature reached about 30K. The teermal runaway current may be used as an important standard for designing a metastable superconducting coil.

Problems in checking condition of transformer oil in service by dielectric loss

Abstract: From the test results on both the oil in service and the oil obtained by accelerated oxidation, it became clear that in the initial stage of deterioration process tan δ is extremely large in spite of the “good” value of ρ, acid number, and interfacial tension and its magnitude is influenced by air, sunlight, and temperature.