A.S.T.M. committee on insulating materials meets

At a 2 day session on March 19 and 20 in New York, N. Y., committee. D-9 on electrical insulating materials of the American Society for Testing Materials reported much progress in advancing its work. In addition to completing work with regard to revisions of standard and tentative specifications and tests, there was outstanding discussion at the main committee and subcommittee meetings centering around such items as test cells for power factor and resistivity measurement of insulating oils, dielectric strength test of sheet and tape material, and conditioning requirements. In connection with insulating oils, committee D-9 has been attempting to secure a suitable test cell that would be inexpensive, but at the same time accurate and convenient to use. Several types of cells have been compared, and the laboratory results prompted considerable discussion. This involved the extremes in accuracy that miglit be desired by different interests, such as cable oil manufacturers, cable manufacturers, and operating companies. It is reported that these discussions and tests are bringing to light the desired information concerning the exactness of the present knowledge and limitations of equipment and measuring devices for power factor and resistivity of liquid insulation.