Nautel NV30LT-N Operation & Maintenance Manual

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Nautel NV30LT-N Operation & Maintenance Manual Manual pdf 9 page image

NV30LT-N OPERATIONS & MAINTENANCE MANUAL DESCRIPTIONVERSION 0.1 2015-03-01 PAGE 3.1.1SECTION 3.1: DESCRIPTIONThis section provides a high-level description of the transmitter’s key sections. The transmitter circuitryis subdivided into four basic stages: Ac-Dc Power Stage Control/Monitor Stage - see page 3.1.3 RF Drive Stage - see page 3.1.4 RF Power Stage - see page 3.1.5Refer to the functional block diagram, Figure 3.1.1 on page 3.1.11.NV30LT-N Electrical SchematicsSome descriptions in this section refer to electrical schematics (SD-#s) . These are located in Section 4 ofthe NV30LT-N Troubleshooting Manual.Ac-Dc Power StageSee electrical schematic Figures SD-1A/B/C SD-2 and SD-3. The ac-dc power stage provides power tooperate the low voltage power supplies, which generate the 40 to 48 V dc voltage that is converted tothe low level dc voltages (±15 V and +5 V) used throughout the transmitter. This voltage is alsoconditioned to operate cooling fans in the RF power module, reject load assemblies and splitterassembly. The ac-dc power stage also converts the ac power source to a positive dc voltage (PA volts)for the transmitter's RF power amplifiers and exciter(s). The transmitter accepts a wide range of acinput voltage options: 3-phase, **175 - 265 V ac (208 V ac nominal) 3-phase, **303 - 459 V ac (380 V ac nominal) 1-phase, **175 - 265 V ac (240 V ac nominal)NOTE: ** - The NV30LT-N’s full ac input range is 90 - 265 V ac (or 156 - 459 V ac, as applicable), but RFoutput power is limited when the voltage is less than 175 V ac (or 303 V ac, as applicable).The ac-dc power stage comprises ac input terminal block TB1, power supply interface PWBs (A1, A17and A33), low voltage power supply (LVPS) modules 1A (U2), 1B (U3, if purchased), and power supplymodules (U4 through U11 and U14 through U29), two for each of the 12 RF power modules. There arethree amber LED pilot lamps (DS1 through DS3), located in the bottom, rear of the cabinet, that indicatethe presence of each ac phase. Ac voltage is distributed from TB1 to TB2 (power rack 1) TB3 (powerrack 2) and TB4 (power rack 3).