ASTM D149-97A PDF
May 26, 2020 | by admin
Buy ASTM Da() Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at. Dielectric Strength ASTM D, IEC Scope: Dielectric Strength is a measure of the electrical strength of a material as an insulator. Dielectric strength is. ASTM DA – Designation: D – 97a (Reapproved ) An American National Standard Standa.
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If no electrodes have been speci? This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ve years and if not revised, either reapproved or withdrawn.
Unless the breakdown path between the electrodes is solely xstm the solid, results in one medium cannot be compared with those in a different medium.
Dielectric Strength ASTM D, IEC
For such materials, the bath must be of such design that it will not be necessary to expose the specimens to air before testing. The following discussion applies only to solid and semisolid materials. This type of failure, usually associated with slow-rise tests at elevated temperatures, will in some cases be reversible, that is, it is possible that recovery of the dielectric strength will occur if the specimen is allowed to cool to its original test temperature before reapplying voltage.
Similar requirements shall apply to the procedure used to increase the voltage between successive steps. Through our network of over 43, people in 1, laboratories and offices in countries, Intertek provides quality and safety solutions to a wide range of industries around the world.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every? D — 09 Preferred starting voltages, Vs are 0. Standards which refer to this method should determine for the material with which that standard is concerned the applicability of this precision statement to that particular material.
Within the limits speci? Due to copyright restrictions, we are not able to provide copies of standards. However, the longer-time tests, Methods B and C, which usually will give lower test results, will potentially give more meaningful results when different materials are being compared with each other.
This will usually reduce the probability of surface? If prolonged current follows breakdown it will result in unnecessary burning of the test specimens, pitting of the electrodes, and contamination of any liquid surrounding medium.
In general, the breakdown voltage will tend to increase with increasing rate of voltage application.
D astn 97a Reapproved An American National Standard Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies1 This standard is issued under the xed 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.
However, this test method may be used at any frequency from 25 to Hz. Since the electrode separation can be xed at will in such cases, it is customary to perform dielectric strength tests on liquids and usually on fusible solids, with electrodes having a standardized xed spacing.
Dielectric strength is calculated by dividing the breakdown voltage by the thickness of the sample. This will usually reduce the probability of surface ashover. If tests are to be made at other than room v149-97a, the bath must be provided with a means for heating or cooling the liquid, and with a means to ensure uniform temperature.
In many cases it is specied that specimens to be tested in insulating oil are to be previously impregnated with the oil and not removed from the oil before testing see Practice D Dielectric breakdown often occurs in an area of the test specimen other than that where the?
If the time to breakdown cannot be adhered to, the time shall be made a part of the report. Weak spots within the volume under stress sometimes determine the test results. Whitehead10 that in order to avoid discharges in the surrounding medium prior to reaching the breakdown voltage of the solid test specimen, in alternating voltage tests it is necessary that Em? If breakdown occurs prior to the end of the holding period at any step, the dielectric withstand voltage, Vws, for the specimen is taken as the voltage at the last completed step.
Dielectric Strength ASTM D149, IEC 60243
Except in cases where the effect of exposure on dielectric strength is being investigated, it is customary to control or limit aetm relative humidity effects by standard conditioning procedures.
Other dielectric uids may be used as surrounding mediums if specied. Since the dielectric astmm is so dependent upon thickness it is meaningless to report dielectric strength data for a material without stating the thickness of the test specimens used. D-7, Glenway Ave. If failure occurred while the voltage was being increased to the starting voltage the failure time shall be zero. Differences between this method and IEC are largely editorial.
Work Item s – proposed revisions of this standard. C The electrodes surfaces shall be polished and free from irregularities resulting from previous testing. Referenced Documents purchase separately The ast listed below are referenced within the subject standard but are not provided as part of the standard.
Hence, its importance will depend to a large extent upon the nature of the material being tested.
Since the electrode separation can be? The outer few layers of roll material, the top sheets of a package of sheets, or material immediately next to an edge of a sheet or roll should be avoided, unless the presence or proximity of defects or discontinuities is of interest in the investigation of the material. In most cases, tests using Type 7 electrodes are made with the plane of the electrode surfaces in a vertical position. ASTM D 97a With the exception of Type 5 electrodes, no attempt has been made to suggest electrode systems for other than?
Global Reach Intertek is the industry leader with over 42, people in 1, locations in over countries. See also Appendix X1.
This may be necessary for specimens that have not been dried and impregnated with oil, as well as for those which have been prepared in accordance with Practice Dfor example. Method A is the most commonly-used test for quality-control tests. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
However, this test method is suitable for use at any frequency from 25 to Hz. Dielectric Strength is a measure of the electrical strength of a material as an insulator.
The material of the gaskets or seals around the electrodes has the potential to in? At frequencies above Hz dielectric heating may be a problem. Conditioning times for these materials shall be sufficiently long to permit the specimens to reach moisture equilibrium as well as temperature equilibrium.