Nautel VS300, Operation And Maintenance Manual

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VS300 Operations and Maintenance Manual Description
Issue 8.0 2016-03-01 Page 1-1
Section 1: Description
Refer to the functional block diagram:
Block Diagram - VS300 Transmitter
- see page 1-7 .
This section provides a high-level description of the transmitter’s key sections. The transmitter
circuitry is subdivided into four basic stages:
• Ac-dc power stage
• Exciter/control stage - see page 1-3
• RF drive stage - see page 1-4
• RF power stage - see page 1-4
VS300 electrical schematics
Some descriptions in this section refer to electrical schematics (SD-#s) . These are located in
Section 5 of the
VS300 Troubleshooting Manual .
Ac-dc power stage
See also electrical schematic Figure
SD-1
.
The ac-dc power stage converts the ac power source to a positive dc voltage (PA volts) for the
transmitter's pre-amp/IPA PWB and PA PWBs. The transmitter accepts a 1-phase ac input voltage
that is between 180 and 264 V ac (208 V ac nominal).
The ac-dc power stage pr48 V to operate the RF power stage’s cooling fan as well as the low
level dc voltages (+15 V and +5 V) for the control/monitoring circuitry used throughout the
transmitter.
The ac-dc power stage consists of ac power entrance U1, circuit breaker CB1, power supply module
U2, LVPS module U3, +48 V power supply module U4 and PS distribution PWB A2.