To test the float, first drain the wash tank. Then open
inspection should not be limited to a visual examination,
the access cover to remove the float from the tank. Of
but also should include checking for loose electrical
connections and mechanical parts.
c o u r s e , you must follow all applicable safety
precautions, including those for tagging the system out
C h e c k the condition of control wiring to the
of service and securing the electrical power. Next, using
solenoid valves and replace it if necessary. Check all
an ohmmeter, tip or raise the float while reading the
electrical connections for tightness and all wiring for
resistance value at the connections. If there is no change
frayed or broken leads. Check the printed circuit card
in the resistance, the switch in the float is faulty. Since
for signs of overheating around the resistors.
the contacts are sealed inside the float, you cannot repair
TESTING. Testing the water wash system should
the switch. You must, therefore, remove and replace the
a l s o be accomplished through PMS. In fact, the
float.
components of the system should be tested during a
HEATERS. A heater is located in the wash tank of
water wash cycle. As a GSE, you will be looking for any
the FFG-7 class water wash system. It is used to heat the
signs of electrical trouble. If you are called upon to
water wash solution (if required). You can energize the
investigate a problem with the water wash system, you
heater by depressing the ON push button on the heater's
m u s t understand how the system operates. This
magnetic controller.
knowledge will help you to cut down maintenance time.
Troubleshooting the heater is a simple task for a
GSE. Just take a resistance reading on the input leads to
Troubleshooting
the heater. Refer to the manufacturer's technical manual
to find the correct ohmic value for the heater. If the
r e a d i n g is within tolerance, check the magnetic
Troubleshooting the water wash system presents no
c o n t r o l l e r for a fault. Use the maintenance and
new techniques. Earlier in this chapter we discussed the
troubleshooting procedures for magnetic controllers we
procedures you should use to troubleshoot and repair
discussed earlier in this chapter.
many of the components of the water wash system, such
as the solenoids, microswitches, and controllers. In the
following paragraphs, we will limit our discussion to the
POWER SUPPLIES
procedures you will use to maintain and repair level
switches (float switches) and heaters.
In today's Navy, all electronic equipment requires
some form of power supply. On gas turbine-powered
LEVEL SWITCHES. Level switches are used in
ships, the electronic control consoles contain many
water wash systems of gas turbines for different reasons,
p o w e r supplies. Although the appearance and
depending on the system installed. On FFG-7 class
construction of these power supplies may differ, the
ships, there are three level switches in the water wash
basic operation is the same. In this section, we will
tank One switch provides a high-level signal for logic
discuss the components and the operation of a basic
circuits in the propulsion control system (PCS). Another
power supply. We will also discuss the maintenance and
switch provides a low-level signal for the logic circuits
t r o u b l e s h o o t i n g techniques involved with power
in the PCS. The other switch controls the energizing of
supplies.
the tank heater. On the DD-, CG-, and DDG-class ships,
one level switch is installed in the water wash system.
It is beyond the scope of this TRAMAN to try to
This switch provides a signal to illuminate the water
d i s c u s s all types of power supplies used on gas
wash TANK EMPTY indicator lights at the local
t u r b i n e - p o w e r e d ships. The differences are too
console. The LCAC system also has one level switch. It
abundant; therefore, we will discuss only the common
is located in the supply tank and provides a FULL
points of interest. For a more detailed description, refer
indication at the fill connection.
to the technical manual that applies to your ship's
equipment.
M o s t floats used inside the wash tanks are
maintenance-free. The switch contacts are sealed inside
BASIC POWER SUPPLY
a bell-shaped float. A wire extends out of the top of the
float to allow for connection to the circuits. As the float
rises and tips over, the contacts close, completing the
Most power supplies are made up of four basic
circuit to the water wash system's electronics. If the float
sections: a (1) transformer, (2) rectifier, (3) filter, and
fails to operate, you must gain access to the float to
(4) regulator. Study figure 5-32, which shows the block
replace it.
diagram of the basic power supply.
5-40
