The process change of epoxy resin laminated board
The dielectric loss tangent of the epoxy resin laminated board is converted into thermal energy under the action of AC voltage and this part of energy is called dielectric loss. Dielectric loss is the loss caused by the leakage conduction current caused by the conductance in the dielectric and the energy loss caused by the periodic polarization of the dielectric. This is because the charged particles in the dielectric are moving under the action of AC voltage and part of the energy they absorb in the electric field is transferred to the surrounding molecules, so that the energy of the electric field is converted into the thermal oscillation of the molecule. When a DC voltage is applied to the dielectric, three types of current flow through the dielectric, instantaneous charging current, absorption current, and leakage conduction current. When an alternating voltage is applied, the instantaneous charging current can only produce a capacitive current; the leakage conduction current is in phase with the voltage; the absorption current formed by the slow relaxation polarization has both active current components and reactive current components. The voltage is in phase, epoxy resin laminated board can cause dielectric loss, and the vector relationship between the current flowing in the dielectric and the voltage is shown in figure 1-1.
The residual angle 6 of the current and voltage phase angle difference φ is called the loss angle. The tangent of 6 tan6 is called the value of dielectric loss tangent. In electrical engineering, tan6 is commonly used as a parameter to measure dielectric loss which is an important dielectric property of insulating materials. 1.2.4 Breakdown strength. When the strength of the electric field applied to the insulating material is higher. Epoxy resin laminated board will cause the current through the insulating material to increase sharply, the insulating material will crack or decompose, and the insulating property will be completely lost. This phenomenon This is called insulation breakdown. The voltage of epoxy resin laminated board which breakdown occurs is called breakdown voltage and the electric field strength at breakdown is called breakdown strength. The unit is kW / mr. The breakdown of solid insulating materials can be roughly divided into electrical breakdown, thermal breakdown and discharge breakdown. Under the action of a strong electric field, the electrical particles inside the insulating material move violently, collision ionization occurs, the molecular structure is destroyed and the electrical conductivity is increased, so that the final breakdown is called electrical breakdown; under the action of a strong electric field, the dielectric material occurs due to dielectric loss If the heat of the epoxy board is too late, epoxy resin laminated board will cause the internal temperature of the insulating material to rise, causing the molecular structure to break down and breakdown that called thermal breakdown. Under the action of a strong electric field, the bubbles contained in the insulating material will collide first Ionization discharges and the impurities also vaporize due to the heating of the electric field. The vaporization of the impurities generates bubbles, so that the bubble discharge further develops, resulting in breakdown of the entire material called discharge breakdown. Breakdown voltage is the voltage at which the sample breaks down under the specified test conditions in the continuous boost test.
Electric strength refers to the quotient of the distance between the breakdown voltage and the applied voltage under the specified test conditions. The electrical strength test results of epoxy resin laminated board can be used to detect changes or deviations in performance from normal values due to process changes, aging conditions, or other manufacturing or environmental conditions. Flashover refers to the loss of insulation performance of the gas or liquid medium around the sample and the electrode when subjected to electrical stress. The resulting test circuit current of epoxy resin laminated board causes the corresponding circuit breaker to operate. The appearance of carbonization channels or the breakdown of the penetrating sample can be used to distinguish whether the test is a breakdown or a network.