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5.C.(3)
Primary Power and Circuit Breaker Requirements
All units in the KHF 1050 system should be protected by circuit breakers in the
positive primary power lines. The KPA 1052 should use an individually
dedicated 30 amp slow-acting circuit breaker. The KAC 1052 and KRX 1053
can share a common 5 amp circuit breaker, or be individually protected by a 5
amp circuit breaker for the KAC 1052 and a 2 amp circuit for the KRX 1053. In
a dual installation, the KAC 1052 and KRX 1053 must share a circuit breaker.
If a PS440 controller is used in the system, it can share a circuit breaker with
the KRX 1053. An MC-850 or an RM-855 must not share a circuit breaker with
any HF system component.
Shielding of the 28V primary power lines is optional. In applications where these
power lines are routed close to the HF antenna or other RF sources, shielding
of those lines will reduce the potential for RF energy getting fed back into the
aircraft power bus.
5.C.(4)
High-Voltage Concerns
The RF voltage at the antenna can be several thousand volts or more,
depending on the operating frequency and the impedance of the antenna. The
feedline components that connect to the center pin of P10528 on the KAC 1052,
as well as the antenna itself, can exhibit dangerous levels of RF voltage. Any
antenna components or feed-line components that are exposed have the
potential to develop corona at high altitudes or to arc to nearby objects. Care
should be taken to ensure proper safety measures are observed. These
measures include:
•
No person should be able to touch a high voltage point or come within one
foot (0.3m) of a high voltage point when the KHF 1050 is transmitting. Also
observe the RF Exposure requirements described in
Antenna Location"
•
Exposed conductors should be free of sharp corners or edges. Rounded
surfaces are less likely to develop corona or arcing.
•
A minimum of 1.5 inches (38 mm) of separation should be allowed between
the high-voltage conductor and other conductive or partially conductive
objects or surfaces. Two inches (51 mm) or more of separation may be
required in some circumstances.
•
Care should be taken to ensure that corona or arcing does not occur in any
area where it could present a fire or explosion hazard.
•
In areas where corona or arcing can not be tolerated, a fully shielded coaxial
feedline and feedthrough must be utilized.
•
The HN connectors on the antenna feed cable should be well tightened and
the mating surfaces kept clean and dry. Cables or connectors that show
evidence of contamination or arcing damage should be replaced.
Revison 2
N
KHF 1050 SYSTEM INSTALLATION MANUAL
.
23-10-09
Paragraph "5.B.(5)
Page 2014
Apr/2006
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