AR 1000T2G8B, Руководство по эксплуатации и обслуживанию

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Model 1000T2G8B
6 Rev -
port. The residual harmonics are typically less than –20dBc, low enough in power that they can be further
reduced, as needed, by a reflective filter without harm to the TWTs.
A directional coupler is installed at the magic tee output for power metering, sample port and VSWR
protection for the tubes. A reflected power foldback circuit utilizing the reflected power port reduces the
system’s gain under conditions of high VSWR so that a gradual increase in reflected power will not result in a
VSWR fault.
The RF output is WRD-250 waveguide.
The control module monitors and controls the RF combiner assembly via the switcher-combiner interface
board (A27444-001). This board generates the analog voltage that controls the variable attenuator and has A-
to-D converters for metering the power levels.
The TWTs are mounted on cooling units (A28036-000). Each cooling unit contains a high density heat sink, a
400 Hz cooling fan, and a fan inverter that operates from the AC line.
2.4 DESCRIPTION OF THE TWT POWER SUPPLIES
The two TWT power supplies are housed in separate 19” chassis 3 rack units (5.25") high. Each power supply
chassis contains a TWT power supply assembly (A24801-501), an HPA interface board (A25444-000), as
well as an AC input line filter and a front panel circuit breaker. In addition, each chassis has a 400 Hz cooling
fan and a fan inverter (A23692-000).
The power supply assembly is of modular construction. Low voltage power for logic and control of the entire
power supply assembly is provided by the low voltage power supply module (A23687-001). Control logic
and TWT protection circuits are contained in the HPA logic and Control Assembly (A16485-000).
The Heater Power Supply Module (A10010-000) powers the TWT DC heater. Bias and pulse top voltage for
the TWT grid are provided by the Modulator Assembly (A21422-000).
The high voltage power supply consists of the following: the Power Factor Correction module (A23683-000)
converts line voltage to DC for the high voltage switching supply. Switching transistors are on the Power
Board Assembly (A16487-000), and switching is controlled by the PWM Board (A10017-517). The high
voltage transformer and rectifiers are contained in the Diode Cap Assembly (A21425-500). The high voltage
DC is filtered in the HV Filter Assembly (A21461-500).
Interconnects between the power supply modules are through a motherboard. It is installed in the power
supply finned heat sink. The Motherboard/heat sink assembly is A24823-000.
The cooling air is provided by the 400 Hz fan mounted on the rear panel inside the air outlet grill.
The HPA interface board permits the control module to control the power supply and monitor analog values
and fault status. Control is through the F/O to RS-485 board, which converts the electrical data from the
control module back to fibers to the HPA interface board.