Electric discharging test for coal carbons

✍ Scribed by H. Honda; Y. Sanada; T. Furuta

• Publisher: Elsevier Science
• Year: 1967
• Tongue: English
• Weight: 667 KB
• Volume: 5
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(67)90051-6

✦ Synopsis

Coal carbon electrodes heat treated at temperatures between 800 and 2800°C were tested with electric discharge under various conditions. The electrode specimens were prepared from Akabira weakly-caking coal and from Itmann strongly-coking coal without binder by means of cold molding at pressures of 1000 and 2000 kg/cm2 respectively. The change in the threshold voltage (Avr) before and after a number of short duration discharges was found to be sensitive to temperature and residence time of the heat treatment. The voltage change occurring for a continuous discharge after 5 min (Av,), the size of craters formed, as well as the consumption of the material exhibit minima at HTT of about 2000°C. The voltage change due to pulsed discharges (Ak'i) and the frequency of occurrence of shortcircuiting show a maximum and a minimum. It is concluded that the coal carbon heat treated at about 2000°C is the most stable one against the discharges examined.