3B Strikesorb wp pdf - Limotrique

Problems with the current technology.1. Poor design and assumptions in design.It is common practice in the surge protection industry to connect protection devices in parallel in an effort toachieve higher ratings than just one device alone. It is also commonly assumed that the surge performanceof a number of devices is a simple multiplication of the performance of an individual device. This is not thecase both electrically (Standler (1)) and mechanically. Nobody assumes that by welding together ten familycars they obtain a truck even if it is possible to quote a total horsepower equal to a truck.Electrically it would be possible to match devices but this would need to be across the complete range ofoperation of the device and would therefore be prohibitively expensive. Even semiconductor devicesfabricated on the same wafer vary in performance due to minor defects and /or impurities in the lattice of thesemiconductor material.Poor mechanical design can lead to one individual device always having to handle more energy during anevent than its neighbors. As a rule an electrical transient takes the shortest, most conductive path and whenit goes around corners exerts forces on the current carrying conductors (Lorentz forces). The net result isthat for large transient currents, such as those produced by lightning, TVSS devices often explode as a resultof these forces and energies dissipated in one device rather than in all of the parallel connected devices.This is depicted in the following photograph.Photo 1:Exploded ModuleThere are several TVSS products that attempt to achieve equal path lengths for the devices connected inparallel. These products do lead to an increased resistance to transient events but tend to suffer from longerevents as the characteristics of the devices are affected by temperature and by no means do all the devicesin any of these designs have the same ability to dissipate energy as heat equally.2. Inadequate ratingFailure to identify the threat or its level correctly, if at all, often leads to a TVSS being applied for the wrongreason. There are many claims for protectors, such as speed of operation, that are pointless, not tested and