Nautel XL12, Технические инструкции

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12 000 WATT AM BROADCAST TRANSMITTER
XL12
Page 2-26
01 January 2002
WARNING
COMMISSIONING PROCEDURES
2.4
These procedures are in a step-by-step
format. They will permit a person who is not familiar
with the transmitter to perform required checks.
They should be completed in sequence, as each
procedure establishes settings and contains
prerequisites for subsequent procedures.
NOTE
The transmitter was precisely calibrated and
subjected to a burn-in during manufacture. It
should not be necessary to change any
adjustment, other than the ones specified. If the
tests associated with a procedure indicate that
the preset adjustments are not optimum, perform
the appropriate adjustment procedure as detailed
in section 5 prior to proceeding with additional
tests.
The exciter assemblies are duplicated and are
connected to form an active and a reserve
exciter. The control/monitor panel's
EXCITER
switch setting determines which set is selected as
the active exciter. Refer to the following listings
to determine which PWB/assembly is selected for
a specific
EXCITER
switch
A
or
B
setting.
An optional C-QUAM AM stereo exciter PWB
(A2A2) may be installed on the exciter panel as
exciter A's RF drive source. When this option is
included, the exciter panel's 'A' RF drive PWB
(A2A1A1) will not be installed.
Exciter A Selected (Stereo Option Not Installed)
A - DC Power Supply................................. A2A1A2
A - RF Drive or Freq Synthesizer PWB........ A2A1A1
A - Interphase PDM Driver PWB ................. A2A1A5
A - RF Drive Amplifier....................................A11A1
A - Regulated Power Supply..........................A11A4
Exciter A Selected (Stereo Option Installed)
A - DC Power Supply................................. A2A1A2
A - C-QUAM AM Stereo Exciter PWB............. A2A2
A - Interphase PDM driver PWB.................. A2A1A5
A - RF Drive Amplifier....................................A11A1
A - Regulated Power Supply..........................A11A4
Exciter B Selected
B - DC Power Supply................................. A2A1A3
B - RF Drive or Freq Synthesizer PWB........ A2A1A4
B - Interphase PDM driver PWB.................. A2A1A6
B - RF Drive Amplifier....................................A11A3
B - Regulated Power Supply..........................A11A5
2.4.1 PRECAUTIONS TO BE
OBSERVED:
The transmitter contains many solid
state devices which may be damaged if subjected to
excessive heat or high voltage transients. Every
effort must be taken to ensure circuits are not
overdriven or disconnected from their loads while
turned on. The precautionary information included in
the operating instructions of section 4 should be read
and fully understood prior to applying power and
must be observed during operation.
2.4.2 TURN ON PREREQUISITES:
Verify
the transmitter is ready to turn on as follows:
(a) Verify pre-commissioning requirements of
paragraph 2.2 and 2.3 have been completed.
(b) Ensure AC power is turned off at the service
entrance.
(c) Terminate the transmitter's RF output into a
precision, 50 ohm, resistive, 20kW, dummy load
that has provision to accurately display the RF
power being applied to it.
(d) Verify the ground wand is properly stored, all
panels are installed (ensure their attaching
hardware is firmly tightened) and the rear door
is closed and locked.
(e) Place or verify the EMERGENCY ON/OFF switch,
which is immediately below the control/
monitor panel, is pulled out (
ON position).
If a jumper is placed between interlock inputs
TB1-25/TB1-26 on the remote interface PWB,
safety features controlled by the external
interlocks will be disabled. A fail safe method of
alerting personnel to this fact should be
implemented. Voltages which are dangerous to
life will be present on the RF output stages and
the antenna system if the transmitter is turned on.
(f) Close all external interlocks or connect a
temporary jumper wire between TB1-25 and
TB1-26 of the remote interface PWB.
(g) Configure the audio input circuits for a
common source for exciter 'A' and 'B' by
setting the exciter interface PWB's
AUDIO
SOURCE
switch to its
SINGLE
position.