The Journal of the Institute of Electrical Engineers of Japan
Online ISSN : 2187-6797
Print ISSN : 0020-2878
ISSN-L : 0020-2878
Volume 46, Issue 457
Displaying 1-11 of 11 articles from this issue
  • M. EZOE
    1926 Volume 46 Issue 457 Pages 827-852
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    In reference to extra-high-tension insulators, we state the progress of its development, the various causes of its deterioration and its ideal improvement. Accordingly we state the characteristics of porcelain itself and the testing process of porcelain insulators.
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  • K. NISHI, K. IKEDA
    1926 Volume 46 Issue 457 Pages 853-871
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    In the previous study of surface creepage in alternating field, (Surface Creepage and High-Voltage Insulation, J.A.I.E.E. Nov 1920, pp. 949-959) this phenomenon was found to be associated with the accurnulation of charge on the surface of dielectrics near the electrodes. During every half-cycle of alternating E. M. F., the residual charge accumulated during the preceding half-cycle is neutralised and fresh charge of opposite sign is accumulated, the latter being neutralised again in the following half-cycle Such a process goes on repeatedly sofar as the alternating field is held high enough to ionize air near electrodes.
    The neutralization of residual charge produces damped oscillations of very complicated nature in the circuit. The maximum value of the current of such oscillation was found to be unexpectedly high, though the effective value is of the order of some hundredths the maximum, probably due to the considerable damping in the oscillation circuits. The frequency of such oscillation was found to lie in the range of radio frequency, though it was unable to be determined definitely. Another peculier feature of the damped oscillations is their unidirectional property, i.e. such oscillations are prodaced only when the corona starting electrode is in negative half-cycle.
    In high voltage testing, if a surface corona is started anywhere in the circuit, the high frequency damped oscillation will be superimposed on the alternating E.M.F. of power frequency, it follows that:-
    (1) In pressure test or dielectric strength test, the insulating material is liable to be over-stressed.
    (2) A sphere gap for voltage measurement would discharge at apparently lower voltage.
    (3) The flash-over value of insulators, bushings etc. would be indefinite in flash over test.
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  • SABURO OSHIDA
    1926 Volume 46 Issue 457 Pages 872-884
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    The rear 1926 marks the fiftieth anniversary of the birth of the telephone, and the art of the long distance telephony was developed especially in the last decade.
    In this paper a general review of the long distance telephone cable is presented and a short note on the longest cable in Japan which is now in construetion is described.
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  • TAKESHI OKAMOTO
    1926 Volume 46 Issue 457 Pages 885-898
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    In this paper the electric butt welding of soft steel bars is treated and the conditions in order to obtain good results as well as the advices for practical operators are concluded from numerous experiments and the result obtained from them. In the first place oscillograms are taken to show the amplitudes of the welding current and the voltage across the butt joint and also that between the clamping block and the bar. From these we can ascertain that the voltage across the joint is comparatively small and its initial value is usually less than one volt and even this decreases pretty rapidly owing to the gradual melting of the joint surfaces. On the contrary the voltage between the block and the bar is not so small remains almost constant throughout the welding time and moreover appears on bath sides of the joint. The value of this voltage depends largely on the condition of the surface of the bar, which is more or less covered with rust. These voltages corresponding to a very rusty surface and a polished one are shown on the oscillograms. The rusty survace makes the power loss between the block and the bar large and renders the welding time long and irregular. The voltage across the joint is comparatively small and decreases rapidly as before mentioned, therefore the heat generated at the joint is not so large as might be expected; the head quantily necessary for raising the temperature and melting the part adjacent to the joint is rather produced in the metalle'c part itself owing to the increased resistivity of the metal, thus raising the temperature with acceleration. From this we can conclude that the metal with a smaller resistivity and temperature coefficient is more difficult to weld; that is, for example, copper bars are more difficult to weld than steel bars. In the next place, bars of different diameters were welded with various powers and the corresponding welding times were measured and these relations between the power and time for each diameter are shown by curves, which resemble hyperbolas but gradually deviate from them upwards for smaller power and larger time. This fact shows that the welding with the smaller power requires larger energy and time. The tensile test was made on these welded bars and the result shows that the welds made with smaller power, that is to say, with larger time are smaller in their tensile strength, although this tendency is less remarkable for bars of the larger diameters. In either case we must make the welding time as small as possible. The effect of the spring pressure which is (applied) to the bar axially was tested. Bars were welded under various pressures, but with a constant power, and the result of this test is that the welding time is almost independent of the pressure and remains constant, but the tensile strength generally increases with the pressure. The joint is liable to the oxydation and this the more remarkable the longer the welding time and the less the spring pressure. In order to be able to investigate the physical properties of the welds the knowledge of the maximum temperature along the bar and also the manner of the variation of the temperature is necessary and these are calculated from differential equations containing as many factors as possible, such as the heat transmission from the surface, the temperature coefficient of the resistivity and the heated generated at the joint etc., and these results are shown by curves.
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  • HIROSHI ANDO
    1926 Volume 46 Issue 457 Pages 899-907
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    If we try to amplify ultra short waves such as 50 meters or less by a vacuum tube amplifier, the inter-electrode capacity of the said vacuum tube will have important effect and the tube get a tendency toward oscillation accompanied by a diminution of the amplification per stage. So that untill recently, direct H.F. amplification of such ultra short waves deemed impossible or impracticable. There exists only few amplifying method of such short waves, such as regenerative systems and various derivatives of them.
    The author is engaging on the research of vacuum tube high frequency amplifier especially of a tuned type for many years and devised the method of preventing inter-electrode capacity coupling, which is employed extensively in the broadcast receiving apparatus since then. Now. I improve and as well as to expand my earlier idea. The improved form proved superior than the simple so called neutrodyne system in the 100-300 meter band and much more effective in the ultra short wave region. The following is the first report of the same.
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  • TATSUO ISHIYAMA
    1926 Volume 46 Issue 457 Pages 908-935
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    It is well known that the irregularities of amplitude which exist in the pressure cud current wave of direct current generators, rotary converers and mercury are rectifiers often give disturbances to acoustic instcuments conneeted to the communication circuits. The most conspicuous i regularities of ampliftude are due to (i) slot and commutator harmonies direct current generators and rotary converters, (ii) higher harmonics of 6 times the frequency of the supply alternating current of motary couverters and (iii) higher harmonics of n, 2n, 3n & c times the frequency of the supply alternating current in mercury are rectifiers where n is the number of anodes. In order to absorb such higher harmonics, the use of the resonant shunt wave filter which consists of a static capacity and an inductance connected in series to the terminals of direct current machines has often been proposed by many authors. Although this wave filter is effective for the suppression of inductive disturbances due to higher harmonics in the communication circuits, yet it is not sufficient to protect the direct disturbances to acoustic instruments from irregularities of pressure waves of direct current generators to be used for the plate or filament circuit of vacuum tubes in the wireless communication and for the power source of automatic or common battery telephone systems. The author has analytically investigated the properties of wave filters of different kind and the method of preliminary design of the wave filter which is effective in protecting the direct disturbances Consequently he has found that an aluminium cell condenser can best be applied as a shunt condenser for such wave filters. Also be has deduced the simple formula for the determination of the above wave filters and explained the test results of so designed wave filters with oscillograms.
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  • SHIGEO MOCHIZUKT
    1926 Volume 46 Issue 457 Pages 936-944
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    The Lichteinberg's figure produced by the damped oscillatory discharge is investigated, by arranging electrode to act on the rotary sensitive photographic film, and following facts are observed.
    I. Case with a needle electrode placed on the rotary drum acting as an another electrode.
    (1) When the first half wave is positive, the neg. figure of the next half wave, loses its characteristic form and creeps over the same bath as the previous pos. one.
    (2) When the first half wave is negative, the pos. figure of the next half wave, maintains its characteristic form, but its path is not straight and proceede tangentially near the extremity of the previous neg. charge.
    (3) The ratio of the radius of the pos. and neg. figure of the first half wave, is far greater than that of the next half wave.
    (4) Connecting the two electrodes placed on the rotary film to the lead wires different inductances the figure produced by the electrode with the greater inductance is larger than that produced by the electrode wish the smaller one.
    II. Case with the needle electrodes placed on the opposite sides of a rotary insulator disc.
    While the discharge is in the state of pole-brush, the pos. figure obtained on one surface has longer creeping distance, compared with the neg. one on the opposite surface, but the pos. figure in the state of surface-spark-co one has the same creeping distance with the neg. one, and the discharges of both sides seem to restrain each other.
    Examining the spark by means of a rotating mirror, the lowest frequency of damped oscillatory discharge obtained in these arrangement was ascertained to be the order of about 1.1×105 cycles per sec.
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  • ISAMU YAMAMOTO, KIYOSHI MORITA
    1926 Volume 46 Issue 457 Pages 945-959
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    In order to obtain the Braun Tube figure in a rectangular co-ordinate, it is necessary to use the saw-teeth shaped voltage wave as the time axis, that is to say, the instantaneous value of the time-axis voltage should vary holding the exact linear relation with the time during the complete period.
    The writers tried to employ the secondary induced voltage of a small transformer which is excited by the full wave rectified current obtained by two kenotrons. This secondary voltage was applied between one pair of electrode plates in a Braun Tube and the voltage under test between another pair of plates, and when the fundamental frequency of the latter was an even multiple of that of the time-axis voltage, stationary figures were obtained in a rectangular co ordinate.
    Ideal teme-axis voltage can be obtained when the primary rectified cur-ent has the, parabolic wave form and the transformer has the ideal characteristics, but these conditions are not satisfied exactly in actual case. For practical purpose, the wave form can be seen without appreciable error, taking a portion. of the steady figure which is superposed on the linear part of the time-axis voltage.
    In the present paper, influences of the circuit constants upon the wave form of the secondary induced saw-teeth shaped voltage were first investigated by ordinary Braun Tube figures, (from Fig. P-1 to Fig. P-16) and then thewave forms of Microphone Hammer, Multi-vibrateur and the damped oscillation in a triode circuit were observed by our method in a rectangu ar co-ordinates (Fig. 8. Fig. 9 and Fig. 17-a & b ).
    This paper contains the following items:-
    (1) Introduction
    (2) General consideration
    (3) Experimental results
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  • H. NUKIYAMA, K. KOBAYASHI
    1926 Volume 46 Issue 457 Pages 960-978
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    A confined elastic medium bounded by two surfaces which are able to displace independently is called an acoustic transformer. The theory of the acoustic transformer and a moving coil type telephone receiver are described. Experiments were worked out on an aco stc transformer loaded by an orifice, and coupl d with a moving coil type telephone receiver were measured by changing the volume of the acoustic transformer and the lead. By determination of the constants of the acoustic transformer at every case by analysis of the total mechanical impedance of the vibrating system obtained by measurements of the motional impedances, the theory of the acoustic transformer was confirmed to be applicab'e to any load conditions. In this paper, the theory and experimental results are described in detail.
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  • K. KUROKAWA
    1926 Volume 46 Issue 457 Pages 979-997
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
    The current and displacement impedance graphs as well as those of admittances of simple series circuits of two and three elements are shown when one component of the hyperbolic complex angular velocity -α+jω is varied. Straight lines, circles, parabolas, inverse parabolas, circular cubits and inverse circular cubics appear as such locus graphs. Angular velocities of natural decays or oscillations are also discussed on these graphs.
    A correction of an oscillographic record of damped oscillation is explained as an application of such locus curves. And a transients in impressing to a L-R circuit an oscillating emf. gradually growing is also appended.
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  • [in Japanese]
    1926 Volume 46 Issue 457 Pages 998-1000
    Published: 1926
    Released on J-STAGE: November 20, 2008
    JOURNAL FREE ACCESS
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