1. Solid wire must be used; therefore, the
Solenoid-operated valves
likelihood of wire breakage is increased.
Remote-indicating valves
2. Problems, such as cold flow, can occur with the
Electrical controllers
insulation.
Bus transfer switches
3. Wire wrapping is not suitable for subminiature
assemblies.
The GSE's counterpart, the GSM, performs
maintenance on the mechanical parts of the valves. The
4. There is no wire color coding in machine-wrapped
GSE performs maintenance on all electrical parts of the
assemblies.
valves. These two ratings must work closely with each
5. The process requires clipping off the wrapped
other when performing maintenance on these
portion of the wire and stripping back the insulation to
electromechanical devices.
expose the new wire before you make the next wrap. If
the wire is too short, you must replace it. You cannot
MOTOR-OPERATED VALVES
reuse the same portion of wire in a new wrap because
this area will have been structurally weakened by nicks
Motor-operated valves provide a means for a
from the previous use, and you will weaken it even
console operator to operate essential valves remotely.
further if you reuse it.
Motor-operated valves are found on fuel oil service
tanks, fuel oil storage tanks, and the main seawater
SAFETY PRECAUTIONS
cooling system of some gas turbine-powered ships.
A motor-operated valve is nothing more than a
Use caution when working with wire-wrap
v a l v e , a motor, and a reversing controller. Most
assemblies. Wire-wrap assemblies resemble a bed of
motor-operated valves also contain microswitches to
nails, and several people have become injured by
show the valve's position. The console operator pushes
disregarding the proper safety precautions. Several
either an open or a close push button. The resulting
facial injuries have occurred when technicians have
signal is sent to the reversing controller of the valve,
tried to get a good look at these assemblies from the side.
thereby opening or closing the valve. An actuating rod
You should remember that this position can expose your
in the valve rotates or slides, depressing either the open
eyes to a needless hazard. If you must use this position
or close microswitch. The signal from the microswitch
to get a firsthand view, use sufficient lighting to make
is then sent backup to the console, indicating the valve's
out the details, use small mirrors whenever you can, and
position.
wear safety goggles. When inspecting or repairing the
T h e main t e n a n c e o n moto r - o p e r a t e d val v e s
b a c k planes or other areas of possible damage,
includes inspecting, cleaning, testing, and
remember that ac or dc voltages may still be present.
t r o u b l e s h o o t i n g the motor and controller. These
Always make certain you are using the proper safety
maintenance procedures are the same procedures you
precautions for working with energized equipment.
would use to maintain basic motors and controllers.
These maintenance procedures will be described later in
this chapter.
ELECTROMECHANICAL CONTROL
SYSTEMS MAINTENANCE
SOLENOID-OPERATED
VALVES
Gas turbine-powered ships are becoming more
a u t o m a t e d and complex with each class of ship
Solenoid-operated valves are used extensively on
delivered to the Navy. This complexity is visible inmost
gas turbine-powered ships. These valves are located in
of the equipment the GSEs maintain. Electromechanical
the bleed air system, the start air system, and the prairie
devices have also become more complex. The GSE
and masker air system. Solenoid-operated valves are
rating is responsible for maintaining these
also found on the gas turbine generator and the main
electromechanical devices in peak operating condition.
propulsion turbine systems.
There are several devices on gas turbine ships that
Construction and Operation
are classified as electromechanical devices. These
devices include the following components:
A solenoid-operated valve consists of a valve
( n e e d l e , poppet, or spool) and a solenoid. Most
Motor-operated valves
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