Directed Electronics D800 Manual de Serviço descarregar pdf (Página 21)

These guidelines are designed to facilitate the installation of lightning pro-

tection on all outdoor mounted scoreboards. We recommend owners of out-

door scoreboards install lightning protection, and hope this information

assists you with the installation.

Our warranty, as with most manufacturers’ warranties, excludes vandal-

ism and “acts of God”--which include lightning. With this in mind, we sug-

gest that you check with your local insurance company to investigate pro-

tection for your scoreboard investment.

Lightning protection starts with proper grounding. For CTS score-

boards, a lightning protection system consists of three basic parts:

1. A system of ground rod(s).

2. A conductor system connecting the scoreboard to the

ground rod(s) and the main ground systems.

3. Bonding of the conductor to the scoreboards and ground

rod(s).

Lightning is an interesting and potentially life threatening phenomenon.

It produces currents from a few hundred to over a million amperes and

voltages from a million to a hundred million volts. The nature of lightning

is the same characteristic on which electronic circuits work. Current in an

electronic circuit always seeks “the path of least resistance”. This is the

same for lightning; it seeks the path of least resistance through ionized

atmosphere until it reaches ground potential at the earth. The basic differ-

ence between the currents in lightning and a circuit, other than the magni-

tude, is that the current in a circuit is controlled by various electrical com-

ponents, but lightning is not

controlled. Herin lies its potential for

danger.

A lightning protection system in effect attempts to place some “control”

over this “uncontrolled phenomenon” by shielding equipment from the

effects of harmful conducted or induced currents. The system creates a low

impedance path to ground and effectively diverts the charge away from the

device under protection. Important to note that protection systems

are not guaranteed against direct hits due to the inherent power

involved. Two terms need clarification. First, “conducted currents

” refers

to a direct hit or a sideflash. Second, “induced currents

” refers to a strong

electrical field that can be transferred through the atmosphere to a path of

least resistance.

4-1

Introduction

Lightning Protection Recommendations

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Directed Electronics D800 Manual de Serviço Página 21