ASTM D877 PDF
ASTM D specifies that for insulating fluids to qualify ASTM D – Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using. Page 1. Page 2. Page 3. Page 4. ASTM D DIELECTRIC BREAKDOWN VOLTAGE OF LIQUIDS. This test method describes two procedures, A and B, for determining the electrical breakdown.
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During testing maintain at least two significant digits for each breakdown. For further information refer to RR: A decrease in dielectric strength of the liquid can have an accentuated effect on the electric creepage strength of the solid insulating materials immersed in the liquid.
Refer to Annex A1 for illustrations of measuring edge radius. Procedure A or Procedure B, Procedure A may be used once the single operator precision of Obtain the new mean breakdown value for the ten breakdowns. Retain all breakdown test values. These liquids include petroleum oils, hydrocarbons, and askarels PCB used as insulating and cooling liquids in transformers, cables, and similar apparatus.
ASTM International – Standard References for ASTM D / DM – 13
Alternate procedures utilizing electrode shapes and configurations similar to those in the apparatus and in Test Method D should be used for oil-filled equipment utilizing well-rounded and insulated electrodes. Use the same gage size when conducting comparative tests. The cup shall be designed to permit easy removal of the electrodes for cleaning and polishing, verification that the sharp edge is within the specified tolerance, and to permit easy adjustment of the gap spacing.
Test Method D is not sensitive to low levels of these contaminants. Originally approved in Last previous edition D —87 d877 This condition requires that the disk be machined back to a sharp edge. Record on the label of the sample container identification of the device from which the sample was obtained, the date, and temperature of the sample at sstm time of collection Note 1.
A low-boiling solvent should not be used as its rapid evaporation may cool the cup, causing moisture condensation. If a value lower than expected is obtained, flush or clean the cup as necessary until test results meet the expected value for the known sample. Precision and Bias Active view current version of standard.
Construct the electrodes of polished brass as disks Voltage Application to the Specimen It should be filled to a level not less than If the range is acceptable, report this mean value as the dielectric breakdown voltage.
These may include samples taken from circuit breakers, load tap changers, and other liquids heavily contaminated with insoluble particulate material. The voltage stress distribution between the parallel disk electrodes used in this test method are quasi-uniform and there is substantial stress concentration at the sharp edges of the flat disk faces.
It is important to avoid touching the electrodes or the cleaned gage with the fingers or with portions of the tissue paper or chamois that have been in contact with the hands. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Test Method D is not sensitive to low levels of these contaminants. The breakdown test uses ac voltage in the power-frequency range from 45 to 65 Hz.
Please fill this form, we will try to respond as soon as possible. If the allowable range is exceeded, the error is too large. Therefore, results of two properly conducted tests in different laboratories on the same sample of oil should not differ by more than Breakdown in this test method is dominated by events occurring at the electrode edges.
If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. A low result in this test method indicates the presence of significant concentrations of one or more asrm these contaminants in the liquid tested.
These liquids include petroleum oils, hydrocarbons, and askarels PCB used as insulating and cooling liquids in transformers, cables, and similar apparatus. The use of Procedure B will result in a more accurate value of breakdown voltage when testing such liquids.
Test Vessel ASTM D877, with disc electrodes
If pitting or scratches of the disk faces are found, examine the electrodes in accordance with 7. If the sample shows evidence of free water, the dielectric breakdown test should be waived, and the sample shall be reported as unsatisfactory. If a second series of five breakdowns is required fill the cup with a new specimen in accordance with 8. Procedure A may be used once the single operator precision of has been demonstrated. Prior to starting the test, the sample shall be inspected for the presence of moisture, sludge, metallic particles, or other foreign matter.