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HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
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1.3.3 Signal Interface
Signal interface for signal input and monitoring by remote control is located on top of
the control cabinet. The PA cabinet top is used for the control and monitoring cable
interconnect with the PA cabinet(s) and the monitor sample cables.
1.3.4 RF PA Cabinets
The PA cabinets have independent:
•
AC power feed from a circuit breaker.
•
Cabinet level control system
•
Cooling system, fan and interlock pressure switch
•
Logic power supply
•
50 Volt RF module supplies with control logic
•
Rear Door interlock
•
Cabinet external interlock to protect combining hybrid reject loads. Maintenance can be
performed on one PA cabinet while the others are operating. A block diagram documents
each transmitter configuration in the appropriate drawing package system, sections
through 5.
Refer to paragraph 1.2.9.4 for individual cabinet configurations.
1.3.5 50 Volt Power Supply
These regulated supplies convert the AC power to 50 volts DC for the RF amplifier
modules. Each is rated at 300 amps, and designed to accommodate -10% to +20%
power line voltage changes. Internal supply fault protection is interfaced to the slave
controller.
The PTCD5P1
i
has one supply. Larger PA cabinets have two 50 volt power supplies.
The supply uses SCRs for voltage regulation. When two power supplies are used, one
supply will be connected as a delta load, the other as a wye load to reduce supply
induced AC mains harmonics. Each supply also has a tuned power line harmonic filter.
This is tuned near the 5 harmonic to reduce a possible motor damaging harmonic.
Single cabinet PAs may have optional internal diode ORing to power driver modules
from either supply.
The 50 Volt supply is covered in detail in this manual section 9.
1.3.6 RF Output Systems
The transmitter output network has several functions, depending on the system, including
combining RF amplifiers, removing out-of-band signals, and filtering harmonics from the
outputs. The sharp tuned (Cool Fuel) filter together with the Apex exciter allow higher