THE LIGHTING PROTECTION THEORY
The basic premise behind the use of air terminals or lightning rods, is to provide a more favorable path for lightning to travel, other than a vessel's structure or key piece of equipment. By placing the air terminals in strategic positions, it is widely held that lightning (seek the path of least resistance) will strike the terminal and subsequently be directed to ground.
The lightning rod goes into a corona (point discharge) producing a stream of positively charged ions approximately 10 - 15 meters above the tip. During the "blind" travel of the stepped leader, which is negatively charged, a path of least resistance is sought and provided by the corona of the lightning rod. After the connection of the stepped leader to the rod, a return stroke is created followed by another dart leader and a subsequent return stroke. This series of strokes can occur up to seven times during one strike. In any case, the rod has completed it's task but there is one major flaw in it's mechanics;
The attraction of the rod has brought over 12,000 to 20,000 amps at 100,000 volts within a few feet of the sensitive equipment you want protected. A common occurrence during a lightning strike is that of voltage spikes and transient surges, created as a result of the magnetic field, brought on by the interaction of charges. Even though the air terminal (lightening rod) has provided a path for the lightning to travel, it CANNOT control the direction of the side flash that induces the spikes and surges. These spikes and surges will find their way into electrical and electronic equipment, eventually overloading circuits or vaporizing and damaging sensitive components.
What is even more dangerous, is the fact that it is not practical to equip smaller vessel's with heavy enough gauging of rod and wiring that can successfully handle the conduction of heavy current during a large strike, and can in fact contribute to damage to metal throughhull fittings and holing of the vessel, leading to taking on water and sinking.
Lightening Rod protection system aboard marine vessels.
THE LIGHTNING PREVENTION THEORY
Ionic emission is nature's way of neutralizing a highly charged area, be it a cloud, an object, or the ground surface area. In order for nature to neutralize a highly charged area (which is in fact the actual process we call lightning), there has to be three conditions present 1) a generally negatively charged thunder cloud, 2) a generally positively charged surface area underneath it, and 3) a path between the two charges.
The lightning rod, which uses the point discharge (corona effect) to attract the stepped leader of a thunder cloud, is constantly dissipating ions into the atmosphere. By multiplying the number of discharge points thousands of times, a system was developed to gather the static build up or electrical charge on an object and rapidly dissipate the charge into the atmosphere, in small quantities. The wind and circulation of air particles typically blow these accumulated ions into the atmosphere thereby neutralizing the charge of the object. On a tenuous operational basis, the ground charge never reaches a high enough value to be attractive to a lightning strike.
The preventive theory which acts on the inverse properties of nature is proven every time a lightning strike occurs. Nature neutralizes a cloud by dissipating ions to the earth's surface, lightning prevention systems neutralize your vessel by dissipating ions into the atmosphere. By sufficiently depleting the amount of charge on the vessel's surface area, two of the three elements necessary for a strike to occur have been eliminated, thus a lightning strike has been prevented.
POSITIVE CHARGES DISSIPATE INTO THE ATMOSPHERE,
NEUTRALISING THE CHARGE ON THE STRUCTURE
Lightening Dissipater prevention system to be affixed to vessel's highest point, such as mast or radar arch.
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