Dielectric Testing is an evaluation process conducted on an electrical component by applying a higher voltage than the product’s normal operating voltage. The test is conducted to ensure that the component’s insulating materials will not break down and leak electricity when used in its intended environment.
The term dielectric is used to describe a material or substance that has a high resistance to heat and pressure. These materials are commonly found in the insulators of circuit boards, wires, and other equipment that are used in the power industry. These materials can be made from plastics, rubber, metals, or other materials. They are typically coated with an organic coating to provide better abrasion resistance, which helps to prevent corrosion and electro-migration of the insulator.
When a product or piece of equipment is being tested for its dielectric strength, a number of different tests can be run in order to get the best possible results. The most common type of dielectric withstand test involves the application of a high voltage (typically 1000 volts or more) between two conductors that are separated by an insulating material. The insulating material should “withstand” the application of this high voltage because the material is considered to be fully isolated from both conductors.
There are several ways to perform a dielectric withstand test, but the two most well-known methods are called the “short-time method” and the “slow-rate-of-rise method.” And while the short-time method and slow-rate-of-rise methods are similar, the short-time method is more common and has a lower maximum voltage that can be used to test products. The slow-rate-of-rise method is not as commonly used as it can be very destructive to the insulator and can cause it to fail at any time.
Both tests can be used to evaluate the adequacy of an electrical product’s insulating material, and they can both be done with a variety of test instruments and techniques. But there is a right time and place for each of these tests. The type of test that is right for a product depends on its intended use and the safety that the user requires from it.