System Description Chapter 2

3-kW UHF Transmitter Chapter 2, System Description
835-3, Rev. 0 2-4
the AC distribution assembly (1247-1100) in the right, center rear of the cabinet. The
assembly contains TB1, which connects to the 220 VAC (line 1 to TB1-1, line 2 to TB1-2,
and ground to TB1-3). The AC distribution panel contains one circuit breaker that
supplies the AC to the rest of the cabinet. The input AC is connected to CB1, the main
AC circuit breaker (80 amps).
The output of CB1 has two neon glow tubes, connected in series, that will light when the
circuit breaker is switched on. The AC connects to TB2, which has three MOVs (VR1,
VR2, and VR3) connected to it, one connected from each leg of the input AC to ground
and one across the two legs. The AC output of TB2 connects to five circuit breakers (CB2
through CB6). CB2 is a 10-amp circuit breaker that supplies the AC voltage to (A1) the
IEC outlet strip. The (A1) UHF exciter tray and the UHF exciter tray for the 1-kW
transmitter should connect to the IEC outlet strip. CB3 is a 20-amp circuit breaker that
supplies the AC voltage to (A6) the 600-watt amplifier tray. CB4 is a 20-amp circuit
breaker that supplies the AC voltage to (A7) the 600-watt amplifier tray. The CB5 and
CB6 circuit breakers are not used in the 1-kW transmitter.
When the circuit breaker for the exciters on the exciter cabinet AC distribution panel is
switched on, and the AC circuit breakers on the rear of the trays are on, +12 VDC from
the UHF exciters is supplied to the amplifier array cabinet and the two amplifier trays in
the 1-kW transmitter. The +12 VDC is split six ways in the amplifier array cabinet and
then connected to each of the 600-watt amplifier trays for the operation of the LED
status indicators in the tray.