Dielectric Strength ASTM D149, IEC 60243

10/12/2014 Dielectric Strength ASTM D149, IEC 60243 http://www.intertek.com/polymers/testlopedia/dielectric-strength-astm-d149/ 1/1 Resources: Reference Guide to Evaluating Assembly Failure of Composites and Plastics Polymers and Plastics Global Polymers and Plastics Testing Polymer and Plastic Services A-Z Send us a request E-mail Us [email protected] Call Us +65 6322 8228 Show other contacts Services Polymer and Plastic Services Polymer Testing Laboratory Testlopedia - The Plastics Testing Encyclopedia Analytical Testing of Polymer Composites Testing Tensile Testing Shear Testing Adhesive Testing Weathering Ageing Testing Automotive Plastics Testing Packaging Services Chemical Analysis Materials Analysis Food Contact Services Polymer, Plastic Services A-Z You are here: Home > Services > Polymers and Plastics > Testlopedia > Dielectric Strength ASTM D149, IEC 60243 Dielectric Strength ASTM D149, IEC 60243 Dielectric Strength ASTM D149, IEC 60243 Scope: Dielectric Strength is a measure of the electrical strength of a material as an insulator. Dielectric strength is defined as the maximum voltage required to produce a dielectric breakdown through the material and is expressed as Volts per unit thickness. A higher dielectric strength represents a better quality of insulator. Test Procedure: There are three basic procedures that can be used to determine the dielectric strength of an insulator. These procedures are the short-time method, the slow rate-of-rise method and the step-by-step method. Each of these three methods has the same basic set-up, which consists of the test specimen placed between two electrodes in air or oil. For the most common test, the short-time method, voltage is applied across the two electrodes and raised from zero to dielectric breakdown at a uniform rate. Breakdown is when an electrical burn-through punctures the sample, or decomposition occurs in the specimen. The rate of voltage rise is determined by the time it takes the sample to reach dielectric breakdown. The slow-rate-of rise method starts at 50% of the breakdown voltage as determined by the short-time-method and is increased at a uniform rate. The step-by-step method starts at 50% of the short-time-test then voltage is increased at equal increments for a specified time period until breakdown. The test is sometimes performed in oil to prevent arcing from the electrode to the ground. Specimen size: The recommended specimen type for this test is a 4 inch plaque or larger. Any specimen thickness can be used; however the most common thickness is between 0.8 to 3.2 mm (0.032 to 0.125 inch). Specimens over 2 mm thick are typically tested in oil to decrease the chance of flashover before breakdown. Data: Dielectric strength is calculated by dividing the breakdown voltage by the thickness of the sample. The data is expressed in Volts/mil. The location of the failure is also recorded. A higher dielectric strength represents a better quality of insulator. **Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. Due to copyright restrictions, we are not able to provide copies of standards. Standards can be obtained from appropriate standards authorities. Testlopedia - The Plastics Testing Encyclopedia Dielectric Constant and Dissipation Factor Surface Resistivity, Volume Resistivity, ASTM D257, IEC 60093 Request more information to see how Intertek can help your organization with Dielectric Strength ASTM D149, IEC 60243. © Intertek Group plc. Disclaimer • Terms • Privacy • Cookies | Services • About Us • Contact Us | Follow us:

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Transcript of Dielectric Strength ASTM D149, IEC 60243

10/12/2014 Dielectric Strength ASTM D149, IEC 60243

http://www.intertek.com/polymers/testlopedia/dielectric-strength-astm-d149/ 1/1

Resources:

Reference Guide toEvaluating AssemblyFa i lure of Compos i tes andPlastics

Polymers and Plastics

Global Polymers andPlastics Testing

Polymer and PlasticServices A-Z

Send us a request

E-mail [email protected]

Call Us

+65 6322 8228

Show other contacts

Services

Polymer and PlasticServices

Polymer Testing Laboratory

Testlopedia - The PlasticsTesting Encyclopedia

Analytical Testing of Polymers

Composites Testing

Tensile Testing

Shear Testing

Adhesive Testing

Weathering Ageing Testing

Automotive Plastics Testing

Packaging Services

Chemical Analysis

Materials Analysis

Food Contact Services

Polymer, Plastic ServicesA-Z

You are here: Home > Services > Polymers andPlastics > Testlopedia > Dielectric Strength ASTM D149, IEC 60243

Dielectric Strength ASTM D149, IEC60243

Dielectric Strength ASTM D149, IEC60243

Scope:Dielectric Strength is a measure of the electricalstrength of a material as an insulator. Dielectric strength is defined as themaximum voltage required to produce a dielectric breakdown through the materialand is expressed as Volts per unit thickness. A higher dielectric strength representsa better quality of insulator.

Test Procedure:There are three basic procedures that can be used to determine the dielectricstrength of an insulator. These procedures are the short-time method, the slowrate-of-rise method and the step-by-step method. Each of these three methods hasthe same basic set-up, which consists of the test specimen placed between twoelectrodes in air or oil.

For the most common test, the short-time method, voltage is applied across the two electrodes and raisedfrom zero to dielectric breakdown at a uniform rate. Breakdown is when an electrical burn-through puncturesthe sample, or decomposition occurs in the specimen. The rate of voltage rise is determined by the time ittakes the sample to reach dielectric breakdown.

The slow-rate-of rise method starts at 50% of the breakdown voltage as determined by the short-time-methodand is increased at a uniform rate.

The step-by-step method starts at 50% of the short-time-test then voltage is increased at equal increments fora specified time period until breakdown. The test is sometimes performed in oil to prevent arcing from theelectrode to the ground.

Specimen size:The recommended specimen type for this test is a 4 inch plaque or larger. Any specimen thickness can beused; however the most common thickness is between 0.8 to 3.2 mm (0.032 to 0.125 inch). Specimens over 2mm thick are typically tested in oil to decrease the chance of flashover before breakdown.

Data:Dielectric strength is calculated by dividing the breakdown voltage by the thickness of the sample. The data isexpressed in Volts/mil. The location of the failure is also recorded. A higher dielectric strength represents abetter quality of insulator.

**Please note that this test description is intentionally generic in nature and aimed at providing a descriptivesummary to enhance test understanding. Due to copyright restrictions, we are not able to provide copies ofstandards. Standards can be obtained from appropriate standards authorities.

Testlopedia - The Plastics Testing EncyclopediaDielectric Constant and Dissipation FactorSurface Resistivity, Volume Resistivity, ASTM D257, IEC 60093

Request more information to see how Intertek can help your organization with Dielectric Strength ASTM D149,IEC 60243.

Intertek Group plc. Disclaimer Terms Privacy Cookies | Services About Us Contact Us | Follow us: