Chemical progress on insulating OILS

Work has been continued on methods for evaluating the stability and resistance to sludging of transformer oils. Subcommittee IV, Committee D-9 of the American Society for Testing Materials, is engaged in studying a teat for the rate of formation of sludge in transformer oil samples subjected to a temperature of 120°C., and in contact with oxygen and copper. This committee is also studying a quality control test method in which oxygen, under pressure, is contacted with the oil and copper at 140°C. for twenty-four hours, following which the amount of sludge is determined.