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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Thank you for interesting in our services. We are a non-profit group that run this website to share aatm. We need your help to maintenance this website. Please help us to share our service with your friends. D — 02e1 Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes1 This standard is issued under the fixed designation D ; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision.
A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. These liquids include petroleum oils, hydrocarbons, and askarels PCB used as insulating and cooling liquids in transformers, cables, and similar apparatus. Procedure B, modified in accordance with Section 17 of Test Methods Dis acceptable for testing silicone dielectric liquids if the requirements of 1.
These may include samples taken from circuit breakers, load tap changers, and other liquids heavily contaminated with insoluble particulate material. These examples represent samples that may have large differences between replicate tests. The use of Procedure B will result in a more accurate value of breakdown voltage when testing such liquids. Procedure A may be used once the single operator precision of The breakdown test uses ac voltage aztm the power-frequency range from 45 to 65 Hz.
This test method should be used as recommended by professional organization standards such as IEEE C For further information refer to RR: D787 edition approved Oct.
Originally approved in Last previous edition D —87 Test Method D should be used to determine the breakdown voltage of filtered and degassed liquids.
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. Calibration s shall be traceable to national standards d8777 should be conducted annually or more often. The voltage in the test circuit should be stable enough to be practically unaffected by varying current flowing in the aastm and resistive paths of the test circuit. Nondisruptive discharges in the test circuit should astk reduce the test voltage to such an extent, and for such a time, that the disruptive discharge breakdown voltage of the atm specimen is significantly ast.
It is recommended that the circuit design limit the disruptive current duration and magnitude to low values that will minimize damage to the disks and limit formation of non-soluble materials resulting from the breakdown, but consistent with the d877 of 4.
Automatic equipment should be used to control the voltage rate of rise because of the difficulty of maintaining a uniform voltage rise aastm. The equipment should produce a straight-line voltage-time curve over the operating range of the equipment.
Hipotronics TCDE Oil Dielectric Test Cell for ASTM D testing – Mitchell Instrument Company
Calibrate and label automatic v877 in terms of rate-of-rise. Significance and Use 3. The power-frequency breakdown voltage of a liquid is reduced by the presence of contaminants such as cellulosic fibers, conducting particles, dirt, and water. A low result in this test method indicates the presence of significant concentrations of one or more of these contaminants in the liquid tested.
Test Method D is not sensitive to low levels of these contaminants.
Breakdown in this test method is dominated by events occurring at the electrode edges. 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. Take care to avoid touching the electrodes or the inside of the cup after cleaning. Flush the cup using part of the sample. Fill the cup with a specimen from a sample with a known breakdown voltage.
Make a voltage breakdown test as specified in this test method. If the breakdown voltage is judged in the proper range for the sample with a known breakdown value, the test cup is prepared for testing other samples. 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. Check the disk in at least four locations for each criteria.
Refer to Annex A1 for illustrations of asstm edge radius. Resurfacing may be necessary in order to remove deep pit marks or edge damage. All residue from the buffing must be removed before the electrodes are reinstalled in the s877 cup. This can be accomplished by repeated wiping with lint-free tissue paper saturated with a suitable solvent such as petroleum etherfollowed by solvent rinsing or ultrasonic cleaning.
After the electrodes have been reinstalled in the test cup, clean and adjust spacing in accordance with 7. Construct the electrodes of polished brass as disks The sharp edge shall have a quarter circle radius no greater than 0.
The cup material shall not absorb moisture or the cleaning and test liquids. Construct the cup so that no part is less than 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 d87 gap spacing. The top of the cup shall be maintained at least Adjustment and Care of Electrodes and Test Cup 7.
Hipotronics TCDE Oil Dielectric Test Cell for ASTM D877 testing
If pitting or scratches of the disk faces are found, examine the electrodes in accordance with 7. For severe problems resurfacing may be required. The gap shall be reset in accordance with 7.
Clean and prepare the cup in accordance with 7. The adjustment is made with a standard round gage of 2. Use d87 same gage size when conducting comparative tests.
Astm d 877 – 02 Dielectric Breakdown
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.
After adjustment of the gap spacing, the cup asmt be rinsed with a dry solvent. A low-boiling solvent should not be used as its rapid evaporation may cool the cup, causing moisture condensation. If c877 occurs, the cup should be warmed slightly to evaporate any 8.
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 the time of collection Note 1. Prior to starting the test, the sample shall be inspected for the presence of d787, sludge, metallic particles, or other foreign matter.
If the sample aetm evidence of free water, the dielectric breakdown test should be waived, and the sample shall be reported as unsatisfactory. In order that a representative test specimen containing the impurities may be obtained, invert and swirl the sample container several times before filling the test cup.
Rapid agitation is undesirable, since an excessive amount of air may be introduced into adtm liquid.
Immediately after agitation, use a small portion of the sample to rinse the test cup. The cup shall then be filled slowly with the liquid to be tested in a manner that will avoid entrapment of air. It should be filled to a level not asstm than In order to permit the escape of air, allow the liquid to stand in the cup for not less than 2 min and not more than 3 min before voltage is applied.
If the range is acceptable, report this mean value as the dielectric breakdown voltage. Obtain the new mean breakdown value for the ten breakdowns. If the allowable range is exceeded, the error is too large. Investigate the cause of the error and repeat the tests. When testing high-viscosity liquids in this range, the sample should be allowed to stand until it reaches room temperature.
The sample container should not be swirled as prescribed in 8.
Record the temperature of the sample and ambient temperature. Procedure A or Procedure B, Voltage Application to the Specimen Apply the test voltage as specified in Section 4 until operation of the interrupting equipment.
Record the maximum voltage reached prior to the breakdown. The mean of the five breakdowns shall be considered the dielectric breakdown voltage of the sample, provided the range criteria of Retain all breakdown test values.
If a second series of five breakdowns is required fill the cup with a new specimen in accordance with 8. During testing, maintain at least two significant digits for each breakdown. The mean of the five breakdowns may be reported as the breakdown voltage, provided the range criteria of Retain all breakdown values. During testing maintain at least two significant digits for each breakdown. Precision and Bias Therefore, results of two properly conducted tests by the same operator on the same sample should not differ by more than Therefore, results of two properly conducted tests in different laboratories on the same sample of oil should not differ by more than f877 The gray area represents the disk and the white area represents the gage.
Note both edges fit to the edge of the gage and the disk edge fits in the radius with no gap as in Fig. This disk asgm acceptable, however, consideration should be given to machining the disk to a sharp edge because any degradation will make it unacceptable.
Both sides of the gage are flush with the disk, and the edge of the disk does not fit into the gage. This condition requires that the disk be d877 back to a sharp edge.