ASTM D149-97A PDF
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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It has been shown by S. This will usually reduce the probability of surface ashover. The optimum current setting is not the same for all specimens and depending upon the intended use aastm the material and the purpose of the test, it is often desirable to make tests on a given sample at 3 more than one current setting. This phenomenon is most commonly evidenced during the test by an abrupt visible and audible rupture through the thickness of the specimen, resulting in a visible puncture and decomposition of the specimen in the breakdown area.
A number in parentheses indicates the year of last reapproval. Other electrode and specimen con? This technique is of particular value for research testing.
Some electrode systems for testing in air make use of pressure gaskets around the electrodes to prevent ashover.
G It is acceptable to use other diameters, provided that all parts of the test specimen are at least 15 mm inside the edges of the electrodes. Due to copyright restrictions, we are not able to provide copies of standards. References to this document should specify the particular options to be xstm see 5.
Dielectric Strength ASTM D149, IEC 60243
If the items listed in 5. It is recommended that mineral oil meeting the requirements of Speci? See also Appendix X1.
With the exception of Type 5 electrodes, no attempt has been made d14-97a suggest electrode systems for other than at surface material. Provide means for use at the completion of any test to ground any parts which fall into any of the following cases: D — 97a 6. However, the longer-time tests, Methods B and C, which usually will give lower test results, may give more meaningful results when astmm materials are being compared with each other.
Link to Active This link will always route to the current Active version of the standard. D — 09 Preferred starting voltages, Vs are 0. It is acceptable to use such repeated applications of voltage to give positive evidence of breakdown and to make the breakdown path more visible. If breakdown occurs prior to the end of the holding period at any step, the dielectric withstand voltage, D1449-97a, for the specimen is taken as the voltage at s149-97a last completed step.
Specic hazard statements are given in Section 7.
If no electrodes have been specied, select an applicable one from Table 1, or use other electrodes mutually acceptable to the parties concerned when the standard electrodes cannot be used due to the nature or conguration of the material being tested. In any event the electrodes must be described in the report. Similar requirements shall apply to the procedure used to increase the voltage between successive steps.
In many cases the dielectric strength of a material will be the determining factor in the design of the apparatus in which it is to be used. Motor-driven controls are preferable for making short-time see Solidly ground all electrically conductive parts that any person might come into contact with during the test.
Do not use another document, including those listed in this appendix, as a model for reference to this test method unless there is conformity with 5. It should also be noted that if the solid is porous or capable of being permeated by the immersion medium, the breakdown strength of the solid is directly affected by the electrical properties of immersion medium.
This test method is useful for process control, acceptance or research testing. Active view current version of standard. If the items listed in 5.
In these uses of the test it is the relative value of the breakdown voltage that is important rather than the absolute value. 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 Ozone has a distinctive odor which is initially discernible at low concentrations but sustained inhalation of ozone can cause temporary loss of sensitivity to the scent of ozone.
Therefore there is a great need for a test to evaluate the performance of particular materials at high voltage stress. The breakdown mechanisms usually operate in combination rather than singly.
However, inferences concerning dielectric strength behavior at other than commercial power frequencies 50 to 60 Hz must not be made from results obtained by this method. Method A is the most commonly-used test for quality-control tests.
This type of failure, usually associated with slowrise tests at elevated temperatures, may in some cases be reversible, that is, recovery of the dielectric strength may occur if the specimen is allowed to cool to its original test temperature before reapplying voltage.
Dielectric Strength ASTM D, IEC
Test results are also affected by the electrode geometry. The test is sometimes performed in oil to prevent arcing from the electrode to the ground. If the control is set too high, the circuit will not respond when breakdown occurs; if set too low, it is possible that it will respond to leakage currents, capacitive currents, or partial discharge corona currents or, when the sensing element is located in the primary, to the step-up transformer magnetizing current.
Ozone has a distinctive odor which is initially discernible at low concentrations but sustained inhalation of ozone can cause temporary loss of sensitivity to the scent of ozone.
Use the short-time test unless otherwise speci?
It is acceptable to use other electrodes as speci? B Electrodes are normally made from either brass or stainless steel. Inspection Validating the specifications, value and safety of your raw materials, products and assets. The test values are dependent upon specimen geometry, electrodes, and other variable factors, in addition to the properties d149-79a the sample, so that it is not possible to make a statement of bias.
If the control is set too high, the circuit will not respond when d149–97a occurs; if set too low, it may respond to leakage currents, capacitive currents, or partial discharge corona currents or, when the sensing element is located in the primary, to the step-up transformer magnetizing current. Auditing Consulting Sourcing Training. Therefore there is a great need for a test to evaluate the performance of particular materials at high voltage stress.