Nautel XL12, Технические инструкции

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12 000 WATT AM BROADCAST TRANSMITTER
XL12
Page 4-2
01 January 2002
ELECTROSTATIC PROTECTION
4.5
The transmitter's assemblies contain
semiconductor devices that are susceptible to
damage from electrostatic discharge. Prior to
removing an assembly from the transmitter, and
while servicing an assembly, the following
precautions must be observed:
NOTE
Electrostatic energy is produced when two
insulating materials are rubbed together. A
person wearing rubber-soled shoes, walking
across a nylon carpet or a waxed floor, can
generate an extremely large electrostatic charge.
This effect is magnified during periods of low
humidity. Components such as integrated
circuits, field-effect transistors, thyristors, and
Schottky diodes may be damaged by this high
voltage unless adequate precautions are taken.
4.5.1 PERSONAL DISCHARGING:
Maintainers should be electrically discharged by a
suitable grounding system (anti-static mats, grounding
straps) during removal of an assembly from the
transmitter and while handling the assembly for
maintenance procedures.
4.5.2 HANDLING/STORAGE:
The assembly
should be placed in an anti-static bag when it is not
installed in a host transmitter or when it is not being
subjected to maintenance procedures. Electronic
components should be stored in anti-static materials.
4.5.3 TOOLS/TEST EQUIPMENT:
Testing
and maintenance equipment, including soldering and
unsoldering tools, should be suitable for contact with
static sensitive semiconductor devices.
4.5.4 STRESS CURRENT PROTECTION:
Every precaution should be taken to ensure the static
sensitive semiconductor devices are protected from
unnecessary stress current. This is achieved by
ensuring:
-
current is not flowing when an electrical
connection is broken.
- voltages are not present on external control/
monitoring circuits when they are connected.
PRE-STARTUP CHECKS
4.6
Prior to applying input power to the
transmitter, observe the following:
(a) Verify all assemblies/modules are installed and
mating connectors are fully engaged.
(b) Verify the external input/output wiring is
connected as detailed in section 2.
(c) Visually inspect the internal electrical wiring
for defects such as damaged insulation, broken
wires, wrong connections and/or loose
connections.
(d) Verify all panels/covers are installed and their
attaching hardware is firmly secured.
(e) Verify the transmitter's RF output is terminated
into a 50 ohm load - an antenna that is
interfaced by an appropriate matching system
for normal operation, or a 50 ohm resistive
dummy load that is rated at 20 000 watts for
adjustment and testing procedures.
(f) Verify appropriate primary winding taps of the
power transformer have been selected to
match the voltage of the input power source
(refer to transmitter configuration sheet.)
READING METERS
4.7
The enabled/disabled status of the control/
monitor panel's RF KILOWATTS
, DC
AMPERES and
DC VOLTS meters is determined by the setting of the
STATUS CONTROL - METER ON/OFF
switch. The
switch's setting will toggle between one of two states
each time it is pressed and released. When it is in
the meter enable (on) state, its integral lamp will be
turned on and all three meters will be enabled.
When it is in the meter disable (off) state, its integral
lamp will be off and all three meters will be turned
off.
4.7.1 READING RF POWER METER:
The
RF
KILOWATTS
meter displays forward power on the
upper scale and reflected power on the lower scale
when the meter has been enabled (integral lamp of
STATUS CONTROL - METER ON/OFF switch is on).
Parameter to be displayed is selected by pressing/
releasing associated
SELECT METER SCALE switch until
the lamp associated with the desired input parameter
is turned on.