Koin Kawamura

Tracking and Ignition Phenomena of Polyvinyl Chloride Resin under Wet Polluted Conditions

This paper describes tracking and ignition phenomena of distribution cable and sheet specimens of polyvinyl chloride (PVC) resin on the basis of experimental results obtained by a test method conforming to the IEC tracking test method. Also, the processes of tracking associated with the ignition and combustion of PVC resin are discussed. In the tracking test using two kinds of F-Cables made of PVC resin, depending on the shape of the specimens, F-Cables may be ignited. From the results, it is found that a dry band is apt to form on the specimen and that tracking occurs by an arc across the dry band. The jacket is ignited by the arc under the test condition in which the deteriorated parts are always in contact with the open air. For the sheet specimens made of PVC resin, free carbon deposited by the heat of the scintillations forms a band, and the arc is produced between the carbon band and an electrode when the voltage gradient exceeds 14.2 kV/cm. The arc recurrence frequency is from 3 to 8 s-i just before ignition. The sheet specimens compounded with DOP, TCS, plus other mixtures are apt to produce an arc in comparison with the specimen compounded with only DOP and TCS, and the resistance to tracking and ignition is increased by including paraffin chloride and high melting point paraffin.

Processes Contributing to Low DC Tracking Failure

This paper describes the correlation between tracking phenomena and the behavior of dissolved and deposited metals from copper or brass electrodes at the interface between an electrolyte and paper phenolic laminate. The test method resembles the IEC tracking test, but with the application of a low dc voltage. The paper also describes the results of an analysis of the dissolved and deposited metals obtained by electron microscopy and X-ray diffraction. It was found that the dissolved metallic compounds from positive copper or brass electrodes were Cu(OH)Cl and Cu2OH)3C1, or Cu(OH·Cl)2·2H2O and Cu2(OH)3C1, respectively. On the other hand, the deposited metals originating from the negative copper or brass electrodes were Cu or Cu and Zn, respectively. When the deposited metals bridged the electrodes, the test solution was evaporatedby joule heating caused by leakage current in the deposited metals on the insulation surface, after which scintillation appeared at the edge of the positive copper or brass electrodes. Theseprocesses were repeated until tracking took place.

Three-body attachment in oxygen and an air-like nitrogen and oxygen mixture

Calculations of the three-body attachment coefficient eta 3/N, N being the gas number density, in oxygen and an air-like nitrogen and oxygen mixture, are performed using a Boltzmann equation method. First, an appropriate cross-section Qa3 for this attachment process in oxygen is deduced by modifying that of Spence and Schulz (1972) so that the calculated eta 3/N agrees well with the experimental values of Grunberg (1969). Then, the deduced Qa3 is used for the calculation of eta 3/N in an air-like mixture of 79% nitrogen and 21% oxygen. Good agreement is obtained with the eta 3/N values measured for dry air by Hessenauer (1967) at low E/N, where E is the electric field. The variation of eta 3/N2 with N is studied, and it is found that even though the value of Qa3 is assumed to be proportional to N, eta 3/N2 can decrease with increasing N due to the change in the electron energy distribution, caused by the variation of Qa3.

A calculation method for estimating a cross section using a Boltzmann equation analysis

A calculation method is proposed for estimating a momentum transfer cross section or a total cross section (summation of the elastic momentum and inelastic), from electron drift velocity versus E/N data, by a Boltzmann equation method. Here, E is the electric field and N is the gas number density. In this method, the calculation is performed knowing that the electron energy distribution is shifted towards higher energy with increasing electric field. The validity of this method is examined by applying the analysis to a model gas, which consists of elastic momentum transfer and electronic excitation as collisions between an electron and a gas atom. The results show that a good approximation, a correct cross section can be obtained automatically from the electron drift velocity data by this method.

New supporting system for musicotherapy using computer processing

The purpose of this paper is to construct a new supporting system for musicotherapy. The supporting system is a combined system that is composed of two systems. One is an operation system that controls sounds and pictures with a multimedia personal computer. The other is a measuring system that measures four kinds of event-related physiological changes (ERPC) such as electroencephalogram (EEG), electromyogram (EMG), body temperature and micro vibration on the palm. The former system was used as the stimulation source to the subject. The latter system was used for observing the mental condition of the subject. This present report especially focuses the function on the proposed system for measuring the ERPC. In conclusion, a proof examination test that used the proposed system was implemented and the author succeeded in detection and measurement of the ERPC.

Effects of dissolved metals on tracking in organic insulating materials

This paper describes the relation between the dissolved metals which are dissolved from the electrodes and the resistance to tracking on the surfaces of organic insulating materials using a test method which complies with the IEC recommended tracking test.

Design and development of new electrostatic voltmeter using strain gauge

This 50 kV class voltmeter accurately detects the displacement of a thin plate of phosphor bronze in the movable electrode, to which the foil gauges are attached, when DC and AC voltages are applied between the fixed and movable electrodes. The movable aluminum-disc electrode and a strain beam are designed, and an electrostatic voltmeter of 50 kV class and higher is manufactured for trial. The relation between the mechanical system part of the movable electrode and the strain on the strain beam is analyzed mathematically. From the results obtained from the relation between the strain on the strain beam and applied voltage, it is ascertained that the strain varied proportionally to the square of the electric stress between the fixed and movable electrodes. A comparison of experimental results to theoretical values is presented. >

Application of multimedia personal computer to supporting system for vocal diagnosis

Due to the recent introduction and diffusion of multimedia in personal computers, the requirements to apply multimedia to medical techniques and rehabilitation are increasing. The author proposes a supporting system for treating patients with articulation disorders as a technique of vocal rehabilitation which was used with a multimedia personal computer. In this study, first, the author designed the multimedia personal computer which was composed of a multimedia upgrade kit, a multimedia pack with video capture and local area network (LAN) equipment. Next, the supporting system for treating the patients with articulation disorder was structured with the trial multimedia personal computer. Finally, the proof examination test was carried out using the proposed system, and it was confirmed that the function of multimotion which was equipped with the screen division and that the electric flash effect was an effective means as the function to support a language cure.

Articulate reproducing system for speech sound using computer processing in cases with disturbance of speech

This paper d e s c r i b e s t h e development of reproducing system f o r making of t h e art ic u l a t e speech sound u s i n g acomputer proc e s s i n g i n t h e cases w i t h d i s t u r b a n c e of speech. T h i s paper a l s o d e s c r i b e s t h e e x per imenta l r e s u l t s o b t a i n e d by t h e s t r u c t u r e system. I n t h i s s tudy , t h e a u t h o r s proposed t h e d i f f e r e n c e c a l c u l u s as t h e p r o c e s s i n g method of v o i c e s i g n a l f o r speech sound. The used computer program w a s t h e sound ana lyz ing type w i t h v e r s i o n of MS-DOS, I n p a r t i c u l a r , t h i s program had t h e spec i a l f u n c t i o n as t h e a n a l y s i s of v o i c e p r i n t with c o l o r mapping o r w i t h t h r e e dimension, n a l which w a s p rocessed i n t h e computer by means of t h e d i f f e r e n c e c a l c u l u s c o u l d be reproduced c l e a r l y , and it was confirmed t h a t t h e d i s t i n c t p a t t e r n of v o i c e print could be a c q u i r e d by employing t h e proposed computer p r o c e s s i n g i n t h e cases with d i s t u r b a n c e of speech

Effects of natural zeolite filler on tracking in paper phenolic laminate

In order to improve tracking failure, natural zeolite was used as filler in paper phenolic laminate. The X-ray diffraction pattern of the natural zeolite clearly shows the mineral structure. The main mineral is clinoptilolite. This zeolite structure was maintained at test temperatures up to 450 degrees C. The improvement of the resistance to tracking in the natural-zeolite-filled paper phenolic laminate with 0.5 wt.% to 5.0 wt.% was investigated by a test method similar to the IEC tracking test. From the experimental results obtained by the IEC tracking test for copper electrodes, on the basis of comparative indices in the unfilled sample, the increasing percentages of comparative indices in samples with 0.5 wt.% to 5.0 wt.% are about 11% to 37%.<<ETX>>