10/6/10 888-2629-200 1-13
WARNING: Disconnect primary power prior to servicing.
Section 1 Introduction
Maxiva ULX COFDM Series
1.2.7 Transmitter Power Supplies
Three phase AC mains must be supplied to the cabinets via circuit breaker CB23 and
CB24 on the AC mains input assembly (A15). The transmitter can accept 208-240VAC
(Delta or WYE) or 380-415VAC (WYE) by changing jumpers in three areas:
• Terminal boards TB1 and TB2
• Parallel MOV boards (A15A1 & A15A2)
• IPA (driver) and PA backplane boards
If properly jumpered there will be three phase 208-240V AC inputs supplied to each
driver and PA module.
!
CAUTION:
THREE PHASE 440-480VAC AC MAINS CAN ALSO BE USED BUT ONLY WITH
AN EXTERNAL TRANSFORMER WHICH CAN BE ORDERED SEPARATELY
FROM HARRIS.
The 208 to 240VAC is supplied to each PA module’s connector I/O board and then to
the modules AC distribution board. There it is applied to eight AC/DC converters (two
per pallet). Depending on the operating frequency, the AC/DC converter output can be
switched between 44, 46, 48, or 50 VDC, which is supplied to each of the eight FET’s
in the module. There are two FET’s on each of the four pallets in each module.
The control system in the transmitter is powered by two low voltage power supply
(LVPS) modules in the TCU.
1.2.8 Cooling System
The Maxiva COFDM transmitter uses a 50/50 glycol/water cooling system to remove
the majority of the heat away from the transmitter but also has cabinet flushing fans to
remove residual cabinet heat. A simplified block diagram of the liquid cooling system is
shown in Figure 1-8 on page 1-14. A simplified diagram of the liquid cooling system
inside the transmitter cabinet is shown in Figure 1-12 on page 1-21. The cooling system
basically consists of:
a. Cooling system control panel/pump module & heat exchanger units
b. Air purger located at the highest point in the cooling system.
c. Coolant strainer.
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