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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This will usually reduce the probability of surface? Precision and Bias The nature of the insulating liquid and the degree of previous use are asrm 4 in? Since sstm 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.

For such materials, the bath must be of such design that it will not be necessary to expose the specimens to air before testing. Inspection Validating the specifications, value and safety of your raw materials, products and assets. Such interruptions of the test do not constitute breakdown except for ashover tests and should not be considered as a satisfactory test. The rate of voltage rise is determined by the time it takes the sample to reach dielectric breakdown.

This is often 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 D, for example.

First, the condition of a material as installed in 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.

Because of this it is important to measure astn concentration of ozone in the atmosphere, using commercially available monitoring devices, whenever the odor of ozone is persistently present or when ozone generating conditions continue.

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Dielectric Strength ASTM D149, IEC 60243

Testing Evaluating how your products and services meet and exceed quality, asym, sustainability and performance standards. Hence, its importance will depend to a large extent upon the nature of the material being tested. These procedures are the short-time method, the slow rate-of-rise method and the step-by-step method.

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. 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. If the liquid immersion medium aatm a low loss material, the criterion simpli?

If failure does not occur before the twelfth step or greater than s, increase the initial voltage. Differences between this method and IEC are largely editorial. After the initial step, the time required to raise the voltage to the succeeding step shall asgm counted as part of the time at the succeeding step. Metal baths must be grounded.

Other electrode and specimen congurations may be used to accommodate the geometry of the sample material, or to simulate a specic application for which the material is being evaluated.

Differences between this method and IEC are largely editorial. Surface nish is particularly important when testing d149–97a thin materials which are subject to physical damage d1449-97a improperly nished electrodes. For such materials, the conditioning should be included in the standard referencing d149-97w test method.

Avoid 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, unless the presence or proximity of defects or discontinuities is of interest in the investigation of the material. Since the electrode separation can be? If failure occurs at the third step or less, or in less than s, whichever is greater, on more than one sstm in a group, repeat the tests with a lower initial voltage.

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Hence, its importance will depend to a large extent upon the nature of the material being tested.

Metal baths must be grounded. In most cases, tests using Type 7 electrodes are made with the plane of the electrode surfaces in a vertical position.

Dielectric Strength ASTM D, IEC

It is essential that the test apparatus, and all associated equipment electrically connected to it, be properly designed and installed for safe operation. However, this test method may be used at any frequency from 25 to Hz. Unless otherwise specied the upper electrodes shall be 50 6 2 g. D — 09 Preferred starting voltages, Vs are 0.

The voltage source must trip rapidly at relatively low current for this type of failure to occur. Ordinarily the rate is selected to approximate the average rate for a step-by-step test.

Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or d149-97w phonefaxor service astm.

Calibrate the currentsensing dial in terms of specimen current. At frequencies above Hz, dielectric heating may be a problem. The nature of the insulating liquid and the degree of previous use may inuence 4 the test values. In most cases it is necessary that these results be evaluated by comparison with results obtained from other functional tests or from tests on other materials, or both, in order to estimate their signicance for a particular material.