Figure 5-25.--CG-47 CRP electronic enclosure front panel.
pitch commanded. Second, it provides a "shaped" input
This system includes three major interfaces: pitch
to the five-point level detector circuit card. Third, it
control; remote pitch indication; and alarms, indicators,
provides a scaled output signal that represents actual
and sensors. GSEs aboard DDG-51 class ships will be
pitch position.
directly involved with the maintenance of this system.
For this reason, we will briefly describe the three major
interfaces between the ship's control system and the
FFG-7 CLASS SYSTEM
CPP system.
The operation of the electrohydraulic control
Pitch Control
system of the FFG-7 class ships is similar to that of the
CG-47 class ships. The FFG-7 class electrohydraulic
The electrohydraulic servo control valve receives
control system does not have a separate CPP electronics
p i t c h change commands from the ship's main
enclosure. The electronics unit for the CPP system is
propulsion plant control system.
located in the buckets of the local operating panel
(LOP). The OD box on the FFG-7 class ship has the
Remote Pitch Indication
same potentiometer setup as that of the CG-47 class
ship. The pitch of the CPP propeller is established
Remote pitch indication is transferred to the ship's
electrically through a single electrohydraulic pitch
main propulsion plant control system by the temperature
control system. The system provides ahead and astern
compensated pitch indicator (TCPI) and the electronic
propulsion thrust by changing propeller blade pitch
pitch indicator (EPI).
without changing propeller shaft rotation direction.
Alarms, Indicators, and Sensors
DDG-51 CLASS SYSTEM
System pressures, oil levels, filter differential
In the DDG-51 class ships, the pitch of the CPPs is
pressures, and hydraulic oil flow are provided to the
established electrically through two identical
ship's main propulsion plant control system.
electrohydraulic pitch control systems. One is located in
each main engine room. The system provides ahead and
The electrohydraulic servo control valve on a
astern propulsion thrust by changing propeller blade
DDG-51 class ship is an electrically actuated, 4-way
p i t c h without changing propeller shaft rotation
valve with a normally closed center position. The
direction.
m a x i m u m inputs to the valve's torque motor are
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