CPI VZU-6994, Руководство пользователя

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for proper fault handling and display via the detail fault LEDs located through the front
panel access door.
Power Processor Module
The power processor circuits provide the necessary line and load regulation of the input
375 volt DC bus, which is converted via a switch regulator and bridge circuit to a
nominal 200 volt, 21 kHz to drive the high voltage module. A sample of the helix high
voltage output is returned to the switch regulator for error feedback correction and sends
a pulse-width modulated signal through an optical isolator to the switching transistors.
This approach allows careful regulation of the TWT helix and collector voltages and
protects both supplies from over voltage/under voltage or short circuit conditions. Low
voltage outputs are also produced by this assembly (+/-15 VDC and 16 VAC) which are
used to operate various internal circuit functions as well as provide power for the RF
monitor circuit, micro-controller assembly, front panel display, and IPA. Internal sensors
provide the necessary over-current protection functions for these supplies.
High Voltage Module
The high voltage module provides the following key power supply functions: regulated
TWT heater supply, regulated TWT high voltage helix and collector supplies, helix
supply current/voltage monitoring and fault protection. The high voltage module contains
the transformers, rectifiers, filters and voltage/current sense resistors for critical TWT
voltages. The incoming 200 volt, 21 kHz signal is applied to the primary of a multi-
section high voltage transformer which provides all of the high voltage levels necessary
to operate the traveling wave tube. Since the helix and collectors share the same
transformer and regulator, the high voltage circuit design establishes the collector
voltages at 50% (collector #1) and 32% (collector #2) depression below the helix voltage.
This relationship permits optimum efficiency and substantial energy savings while
extending the useful life of the TWT. A separate step-down transformer with rectifier and
filter network is employed to provide the heater voltage.
Control and Display Modules
The Control and Display Modules are designed to assure correct operation of the power
amplifier and easy maintainability with minimal operator training and activity.
Microprocessor circuits along with status and fault LEDs provide automatic sequencing
of CMPA operation and continuous monitoring of critical parameters. If a fault should
occur, the CMPA either recycles back to its state prior to the fault or latches into the
FAULT state. In either case, the appropriate front panel lamp will illuminate. Also, a
detail fault display is located inside the front panel access door which can be used in
assisting a maintenance technician in isolating the fault to a replaceable component or
subassembly. The front panel access door also provides a convenient means of allowing
the user to set features such as system configuration and low RF alarm.
Ku-Band CMPA 04/08 TD-67 Page 5