Insulating materials are important in modern electrical and electronic systems to control electric fields within a system, reduce energy loss, and ensure the efficiency of a system. Though the high dielectric strength and volume resistivity are used to determine the resistance of a material to electrical breakdown and the flow of current, the dielectric loss measurement would tell more about the amount of energy being lost as heat during the operation. Measurement of dielectric loss can be used by laboratories to test 1. performance of materials in realistic operating environments and 2. assist in the selection of materials and quality assurance.
Purpose of Dielectric Loss Measurement
The main aim of measuring the dielectric loss is to know how far an insulating material will turn electrical energy into heat when an AC electric field is applied to it. The information plays a vital role in determining the material to use in high-efficiency and high-reliability electrical applications. The data of the dielectric losses is applied in material development, product qualification, failure analysis, and adherence to the electrical performance standards.
Principle of Dielectric Loss Measurement
The loss tangent, also known as the loss delta, or tan, is a common way of expressing dielectric loss and is the ratio of the amount of energy that is lost to the amount of energy that is stored in the dielectric material. In the absence of a direct current, polarization processes in the substance do not follow the varying electric field immediately. This delay causes dissipation of energy, which is quantified as dielectric loss.
Test Procedure Overview
Commonly used dielectric loss test is one in which electrodes are connected to the specimen between electrodes to the LCR meter, impedance analyzer, or dielectric spectrometer. The voltage imposed on it is AC and at designated frequencies and temperatures. The measurement instrument is used to measure capacitance, resistance, and phase angle, based on which dielectric loss and tan 0 values are obtained. They are also able to conduct measurements over a variety of frequencies to determine the performance of materials under various operating conditions.
