Electrical insulation material is used to ensure the unwanted current flow between conductive components. In case the electric field applied to any material goes beyond the dielectric strength, the failure of the insulation will be in the form of electrical breakdown. Testing Breakdown voltage testing is the quantification of this limit under controlled conditions. Its outcomes are necessary to provide safe operation of the components, cables, transformers, capacitors, motors, printed circuit boards, and insulating coatings.
Principle of Breakdown Voltage Testing
The test relies on the usage of a progressively rising voltage between a test sample until electrical breakdown takes place. A sudden increase of current, arcing, or observable damage of the specimen normally indicates breakdown. This breakdown voltage is the voltage at which this failure takes place. This value is the intrinsic dielectric strength of the material and how it is able to resist high electric fields.
Test Method
The breakdown voltage testing is carried out on standardized practices outlined in the international and industrial standards. The sample of the test is arranged between two electrodes of a defined geometry, i.e., parallel plates or spherical or cylindrical electrodes. A fixed rate of ramping the voltage is applied until the breakdown. Depending on the application, the test can be done under AC, DC, or impulse voltage conditions. Several samples are run to cover the variability of the material and provide statistical consistency.
