Hitachi EC702MP-BB3, Operation Manual

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E-Compact MP-BB3 Series
2.5. Atmospheric Discharge Protection System
2.5.1 Lightning rods
The Atmospheric Discharge Protection System consists of the lightning rods and their
elements. The tower and shelter where the equipment will be installed must be protected
against atmospheric discharges by means of lightning arresters.
It is important to determine that all ferrous parts and accessories that make up the
Atmospheric Discharge Protection System should be galvanized.
In the path comprised of the lightning rod to the drainage well, no splicing is allowed,
much less pathways with acute angles (angles of less than 90º).
2.5.2 Protectors
The use of coaxial protectors is advisable for cables connecting external devices
(antennas, microwave heads, tower inverters) to the internal ones. These protectors are
devices equipped with gas spark plugs, which shorten to earth any discharge occurring in
the coaxial cable. They should be kept in the shelter near the equipment and with the
ground wire connected to the ground of the equipment rack.
It is favorable to use Faraday’s Ring or Cage on hilltops and areas of many transmission
sources, which in turn isolates the transmitter from the electromagnetic fields avoiding
interference caused by induction.
2.6 Air Conditioning
2.6.1 Temperature
For better performance and longer equipment life, it is important that, under the shelter,
the temperature is controlled strictly by means of air conditioners. For the shelter’s
design, one should consider the thermal dissipation specified for the transmitter (reported
in BTU / h), the dissipation of the other devices inside the shelter, the thermal load
generated by the solar incident, and other thermal loads present in the shelter. In
addition, it is recommended that the shelter’s internal pressure be slightly positive to
prevent the entry of contaminants. According to the transmission power, the internal
temperature of the shelter should be:
• E-COMPACT LOW POWER TV TRANSMITTERS: from 0º to 35ºC
• E-COMPACT MEDIUM POWER TV TRANSMITTERS: from 0º to 30ºC
• E-COMPACT HIGH-POWER TV TRANSMITTERS: 0º to 25ºC
If Comark equipment is damaged by the lack or inefficiency of the HVAC system, it will NOT
be covered by the factory warranty.