The TUR T1 25 surge protector is designed to prevent surge damage to equipment caused by induced lightning, an indispensable component for protecting electronic products. As electronic devices become increasingly integrated into everyday life, surge protectors are becoming more familiar to everyone. In reality, lightning protection for electronic systems is still a relatively new field, and many issues regarding the selection and application of surge protectors remain controversial. This article explains the response time of surge protectors and the action sequence of multi-stage surge protectors.
Section 2: Operation Sequence of Multi-Level Surge Protectors
When a single-stage surge protector fails to suppress the侵入overvoltage to below the specified protection level, a surge protector with secondary, tertiary, or more stages of nonlinear suppression elements should be used.
Nonlinear componentsRv2AndRv2All are photoresistors, practical in use.RV1Also, it can be used for gas discharge tubes, Rv2Also available are voltage regulators or surge suppression diodes.TVSIsolation components between the poles.ZsIt can be an inductor.LsOr resistanceRsIfRV1AndRV2The conduction voltages are, respectively:Un1AndUn2The components selected are alwaysUn2> Un1。
Someone believes that when the invasive shock wave is added toX-EAlways a first-class fit on the terminals.RV1Primary copper, followed by the second grade. In fact, both primary and second-grade lead-throughs are possible, depending on the following factors:
(1) Intrusion shock wave waveform, primarily the speed of sound in the current wavefront.di/dt）；
(2) Nonlinear componentsRv1AndRV2Conduction VoltageUn1AndUn2Relative size;
(3) Isolation ImpedanceZsThe nature is whether resistive or inductive, and their sizes.
WhenZsFor ResistanceRsAt times, it is typically the secondary pilot that conducts first. After the secondary conducts, when the impulse currentIAscendiRs＋Un2 ≥Un1It's only conductive at level one. After level one is conductive, due to the lower equivalent impedance of the next level under high current,RsThe sum of the equivalent impedance at the second level is much smaller. Therefore, most of the surge current is discharged through the first level, while the current discharged through the second level is significantly smaller. If the first level is a gas discharge tube, the residual voltage after conduction is typically lower than the conduction voltage of the second level.Un2Then, the secondary cutoff is reached, with the remaining surge current discharged entirely through the primary gas discharge tube.
IfZsFor InductorsLs, and the initial rise rate of the侵入 current is quite fast, conditionsLs(di/dt)＋Un2>Un1Met with satisfaction,The primary conductor is first. If the restricted voltage during the primary conduction isUc1(1),Then, as the invasion surge current accelerates in the future.(di/dt)The decline, when conditionsUC1(1) ≥Ls(di/dt)＋Un2When satisfied, the second level conducts. After the second level conducts, the output terminalYThe voltage is suppressed to a lower level.
