Breakdown voltage is the minimum voltage that causes a portion of an insulator to experience electrical breakdown and become electrically conductive. All dielectric materials have a maximum applied field at which they fail and begin to conduct charge, called the dielectric breakdown strength (or alternatively dielectric breakdown voltage). The breakdown occurs either by movement of charge carriers within the dielectric material, result of dielectric and/or Joule heating or compression by electrostatic forces. This breakdown is often accompanied by a sudden and substantial increase in conductivity, resulting in the formation of an electric arc or breakdown path through the insulator.
TESTING PRINCIPLE
The test applies to solid insulating materials. The material to be tested is conditioned at a relative humidity of 25% and 60% and a temperature of 23ᣞC for at least 12 hours. The cylindrical electrode is brought into firm contact with the surface of the material sitting on a grounded metal plate.
Voltage to the electrode is increased gradually until the insulating property of the material breaks down and a large current passes through the sample to the grounded plate. The voltage at this point is the breakdown voltage. The testing is repeated at least 5 times at different parts of the surface of the material and on the opposite sides of the material.
Breakdown Voltage Test Set up
Applicable Standard
Breakdown voltage testing is performed in accordance with IEC 60243-1, ASTM D3755-20 and Section 9.2 of IEC 61340-4-4
Data interpretation
In the presence of prolific charge generating mechanisms (e.g. pneumatic transfer of powders, charge spraying in the powder coating process) very high levels of surface charge can be generated on an insulating sheet or layer with earthed metal backing. If the breakdown strength of the layer is sufficient to withstand the large field strength in the layer, surface charge densities of the order of 300 μC/m2 enable the discharge to change from a brush discharge into a propagating brush discharge. A propagating brush discharge can release a lot of energy. It is, therefore, capable of igniting almost all flammable gases, vapors and powders and can cause severe electrostatic shocks. By knowing the breakdown voltage, appropriate measures can be put in place to avoid propagating brush discharges in an explosive atmosphere.
When to perform Breakdown Voltage
Breakdown voltage is applied to all insulating materials as well as Flexible Intermediate Bulk Containers (FIBC’s), Sheets, films, fabrics, foils, and coatings. Understanding and specifying the breakdown voltage of insulating materials is crucial in ensuring the reliable and safe operation of electrical equipment, preventing electrical faults or failures due to inadequate insulation performance under high-voltage conditions.
Why work with Prime Process Safety Center
- Prime Process Safety Center is a leader in process safety testing with very experienced laboratory personnel. At Prime Process Safety Center our goal is to provide accurate, reliable and defensible data that meets industry and regulatory standards. We understand the need for the quality of your data, and we work assiduously to achieve just that.
- We are knowledgeable and experienced in performing breakdown voltage tests, ensuring accurate and reliable results.
- We have state-of-the-art breakdown voltage testing equipment, providing precise and sensitive measurements.
- We follow strict testing protocols and quality control measures to ensure consistent and reliable test results.
- Our team can interpret and analyze the data obtained from the tests, providing valuable insights and recommendations for your specific application or research.
FAQs
What is Breakdown Voltage?
Answer: Breakdown voltage is the voltage level at which an insulating material loses its ability to resist the flow of electrical current and experiences a significant increase in conductivity, leading to electrical breakdown or failure.
How is Breakdown Voltage Measured?
Answer: Breakdown voltage is often measured using standardized tests such as dielectric strength tests, where the material is subjected to increasing voltage until breakdown occurs.
What Factors Affect the Breakdown Voltage of Insulating Materials?
Answer: Factors influencing breakdown voltage include material composition, purity, thickness, structure, temperature, humidity, surface condition, and presence of defects or impurities.
What are the Types of Breakdowns that Occur in Insulating Materials?
Answer: Breakdown can manifest as partial discharge or complete breakdown. Partial discharge involves localized breakdowns, while complete breakdown involves a sudden and significant increase in current flow.
What Standards Govern Breakdown Voltage Testing?
Answer: Various international standards, such as ASTM (American Society for Testing and Materials) and IEC (International Electrotechnical Commission), provide guidelines for breakdown voltage testing methods.
What Are the Safety Implications of Understanding Breakdown Voltage?
Answer: Understanding breakdown voltage helps in setting safe operating limits, preventing electrical hazards, ensuring equipment safety, and minimizing the risk of electrical failures.
