WATER WASH SYSTEM
and corrective actions in the appropriate technical
manual.
A water wash system is a maintenance feature
When a voltage regulator is not operating properly,
provided to remove dirt, salt, or other foreign deposits
you must observe the symptoms provided to you. You
from the internal parts of a gas turbine. Water washing
must know what the unit is supposed to do before you
is accomplished by spraying a mixture of distilled water
can determine what it is not doing or what it is doing
and cleaning agent into the compressor while the gas
incorrectly. The following list contains several common
turbine is motoring. Rinsing is done in the same manner,
malfunctions that occur in voltage regulators:
using distilled water only.
Open circuits in leads to and from the rectifier
A water wash system is found on the LM2500 GTE
for the DD-, DDG-, CG-, FFG-, and PHM-class ships.
assembly
It is also found on the Allison gas turbine generators on
Open circuits between the exciter field and the
the DD-, DDG-, and CG-class ships. The LCACs have
regulating resistance
a water wash system on Lycoming TF40B main engines
and the Sunstrand T-62T auxiliary power unit. The
Short circuits of the regulator terminals
PHMs also have a water wash system on the Garrett
Obstructions in any of the moving parts
ship's service power unit.
The water wash system on each gas
Loose or faulty connections in various circuits
turbine-powered ship is unique in its own design.
Binding or function in the pilot motor assembly
Although many different types of components are found
in each design, the following electrical components are
common to most water wash systems on gas
Dirt, grease, or other foreign materials on the
turbine-powered ships:
contacts of relays or rheostats
Level switches
Faulty diodes, transistors, capacitors, and other
Solenoid-operated valves
small electronic components
ON/OFF water wash toggle switches
Misalignment of the gears, screw, or rod of the
motor-operated potentiometer assembly
TANK EMPTY indicators
During troubleshooting, you can loosen many of the
Heaters
connections to perform various tests. You can also
Magnetic controllers
remove and replace several parts during these tests.
.
W e will briefly discuss the maintenance and
A voltage regulator is a very sensitive piece of
troubleshooting techniques for these common
equipment. You must make sure to handle its parts with
components.
care. The alignment of limit switches, control relays, and
motor-operated potentiometers can be thrown off by
improper handling. When replacing these components,
Maintenance
make sure to place the parts back in proper alignment to
ensure correct operation. Make sure you use the correct
You can accomplish the maintenance procedures for
soldering and resoldering techniques. (Sometimes,
the components of your ship's water wash system by
more harm than good is done by use of improper
using the basic procedures we have already covered in
soldering techniques.)
this chapter. Like other systems, the water wash system
must be periodically inspected and tested. Failure is
You must also use extreme care when tagging out
o f t e n caused by loose electrical connections and
the voltage regulator for maintenance. Most voltage
inoperative solenoid valves. The keys to maintaining a
regulators have multiple sources of power. When
trouble-free water wash system are thorough
securing power to the voltage regulator, make sure you
inspections and tests.
investigate your ship's particular system. Finally, be
certain you follow all applicable electrical safety
INSPECTION.-- The gas turbine engine should be
precautions whenever you are performing maintenance
water washed according to PMS. During PMS, the
system should be inspected according to the MRC. The
and repair on voltage regulators.
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