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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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Whether your business is local or global, we d14-97a ensure your products meet quality, health, environmental, safety, and social accountability standards for virtually any market around the world.

It is essential that for these materials both the specimen and the electrodes be dened in the specication for the material. D — 97a 6. Last previous edition approved in as D — 97a However, this test method may be used at any frequency from 25 to Hz. Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm.

Care must be taken in machining specimens not to contaminate or mechanically damage them. 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. The dielectric withstand strength is to be calculated from the thickness and the dielectric withstand voltage, Vws.

Dielectric Strength ASTM D149, IEC 60243

References to this document should specify the particular options to be used see. For such materials, the bath must be of such design that it will not be necessary to expose the specimens to air before testing.

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Calibrate the currentsensing dial in terms of specimen current. The breakdown mechanisms usually operate in combination rather than singly. Other electrodes may zstm used as specied in ASTM standards or as agreed upon between seller and purchaser where none of these electrodes in the table is suitable for proper evaluation of the material being tested.

If the items listed in 5. First, the condition of a material as installed xstm apparatus is much different from its condition in this test, particularly with regard to the conguration of the electric eld and the area of material exposed to it, corona, mechanical stress, ambient medium, and association with other materials.

Small baths can in some cases be placed in an oven see 6. Ast, made with horizontal electrodes should not be directly compared with tests made with vertical electrodes, particularly when the tests are made in a liquid surrounding medium.

Provide means for use at the completion of any test to ground any parts which fall into any of the following cases: Generally speaking, the effect of the electrode material is difficult to establish because of the scatter of experimental data. While every effort has been made to include as many as possible of the standards referring to Test Method Dthe list may not be complete, and standards written or revised after publication of this appendix are not included.

The nature of the insulating liquid and the degree of previous use may inuence 4 the test values.

Dielectric Strength ASTM D, IEC

A higher dielectric strength represents a better quality of insulator. However, even materials that absorb little or no moisture may be affected because of greatly increased chemical effects of discharge in the presence of moisture. Unless the breakdown path between the electrodes is solely within the solid, results in one medium cannot be compared with those in a different medium.

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Tests made with horizontal electrodes e149-97a not be directly compared with tests made with vertical electrodes, particularly when the tests are made in a liquid surrounding medium. This critical eld intensity is called the intrinsic dielectric strength. These processes may continue until a complete failure path is formed between the electrodes. The exposure limits are set by governmental agencies and are usually based upon recommendations made by the American Conference of Governmental Industrial Hygienists.

This study made use of one aetm system and one test medium. The device shall disconnect the voltage-source equipment from the power service and protect it from overload as a result of specimen breakdown causing an overload of the testing apparatus.

It is essential that for these materials both the specimen and the electrodes be de? Visual observation of the electrodes and test specimen during the test is frequently desirable.

If aztm circulation of the? If the control is set too high, the circuit will not respond when breakdown 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.

In general, the breakdown voltage will tend to increase with increasing rate of voltage application. Similar requirements shall apply to the procedure used to increase the voltage between successive steps.

In any event the electrodes must be described in d149–97a report.

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