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Volume 1969 (1969)
- Issue 59 Pages 272-
- Issue 58 Pages 224-
- Issue 57 Pages 186-
- Issue 56 Pages 149-
Volume 1969, Issue 58
Displaying 1-7 of 7 articles from this issue
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Kinji KOKUBU, Kanji ISHIKAWA1969 Volume 1969 Issue 58 Pages 224-234
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSBouncing of brushes mounted on a laboratory-made mimic commutator was quantitatively investigated by the so-called electric capacity method. In combination with the measurement of contact potential drop simultaneously examined, following conclusions have been obtained: (1) The brush bounce is affected rather severely by the unevenness of commutator surface than its off-centricity, which takes place further violently as the backward inclination of the surface is steepened, (2) In order to prevent such bouncing of brushes when motor is operated under ordinary conditions the unevenness of commutator surface should be less than 3 microns in depth, and the off-centricity should not exceed 15 microns, (3) It produces fairly good effect for diminishing the bounce to strengthen the brush pressure, if the unevenness is not too large. For the effective suppression, the working points of pressure are desirable to be as close as possible to the trailing side.(4) The critical height of brush bounce at which commutator sparks are transformed into arcs is estimated to be 5-6microns.View full abstractDownload PDF (14105K) -
Kazumaro Koshiishi, Yoshiro Mori1969 Volume 1969 Issue 58 Pages 235-241
Published: October 25, 1969
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSCarbon paste, which is the material of electrode for extrusion forming, is generally considered to be a “Bingham Body”. We made experimental extrusion on the carbon paste by a bench-scale plunger type extruder with various size of cone nozzles.
As a result, it was concluded that the carbon paste slipped on the wall of cylinders at elevated temperatures from 110°C to 130°C, and also the material was almost in steady flow if the position of the piston was apart more than 50 mm from the entrance of the nozzle and the piston speed was less than 0.5 mm/sec, when the extruder having the cylinder, 50 mm in diameter, with the nozzle of 25 mm and 17 mm in diameter. Extrusion pressure, Ppiston, was given, as the following equation on the basis of the Sach's theory, which approximately coincided with the experimental results.
Ppiston=K [(1+1/μncotd) {(A1/A2)μncota-1} +4d/3√3] ·e2μsh/r1
Yield stresses of the carbon paste determined from the above equation were 1.2 Kg/cm2 and 0.5 Kg/cm2 at the temperatures of 110°C and 130°C, respectively.
In order to analyze stresses, we obtain a flow pattern of the carbon paste by the method of Siebel's grid and measured the coordinates of the intersections of the deformed grid. The distribution of the strain velocity, the principal stress tranjectories and the stress distribution were determined from the analysis of the flow pattern using electron data processing system.View full abstractDownload PDF (939K) -
M. Saito, M. Baba, K. Tashiro, T. Tsuzuku1969 Volume 1969 Issue 58 Pages 242-246
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe widths (W) of the stacking faults accompanying by the ribbon dislocations in pure, IC1-doped and Br-doped graphites have been examined to the direct measurement by the transmission electron microscopy at temperatures from 100° to 300°K.
The thermal coefficients 1/W·dW/dT have been found to be 3.4×10-4, 2.2×10-4 and 0×10-4 (°K-1) for the original specimen (pyrolitic graphite, heat treated at 3600°C after deposition) and those doped with IC1 and Br respectively.
A tentative explanation in relation to the interaction energies (E) between dislocations and impurities evaluated through the internal friction study has been proposed, while the dependence of the stacking fault energy on the nature and concentration of impurities has not been well understood yet.View full abstractDownload PDF (805K) -
IV - Relation between Electro-Discharging Properties in Kerosene and Physical Properties of CarbonsT. Furuta, Y. Sanada, H. Honda1969 Volume 1969 Issue 58 Pages 246-250
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCarbon electrodes heat-treated at temperatures between 1000 and 3000°C were tested with electric discharge in kerosene. The electrode specimens tested were coal carbons and pitch bonded petroleum coke carbons. The removal rate of steel, which is faced against carbon cathod by small gap, depends markedly upon physical properties of carbon electrode. The wear rate of carbon electrode in a discharge for 10 min. increases with heat treatment temperature. It is concluded that electric conductivity of carbon electrode play an important role under the pulse discharge in kerosene.View full abstractDownload PDF (599K) -
[in Japanese]1969 Volume 1969 Issue 58 Pages 251-256
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1197K) -
[in Japanese]1969 Volume 1969 Issue 58 Pages 257-262
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (976K) -
[in Japanese]1969 Volume 1969 Issue 58 Pages 263-268
Published: October 25, 1969
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (884K)
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