according to the PMS. There are no tests or inspections
related to SSS clutch assemblies, unless you are
assigned to a CG-47 class ship. Remember, that
particular type of SSS clutch has an internal PT brake
assembly. The ships maintenance action plan
periodically requires that an inspection of the disc
assembly be made and the clearances between the discs
Additionally, you must check the externally
mounted PT and shaft brake assemblies on a regular
basis according to the PMS. These inspections
normally include checking the brake pad thickness
measurements, rotor condition, proper operation of air
or hydraulic actuators, and proper lubrication of vital
Because SSS clutches are reliable, problems that
require troubleshooting are usually minimal. Like all
other gear-driven assemblies, SSS clutches have a
tendency to wear and produce noise with age. Normal
failures are usually limited to faulty position indicator
switches and failures related to the PT brake assemblies.
We will not dwell on the clutch assemblies, but move on
to some of the problems related to the installed brake
assemblies and the ways in which you, the GS
supervisor, can better identify them.
The basic operation of both the PT and shaft brakes
is the same as the disc brake system installed in most
automobiles. All brake systems require some type of
medium (air, oil, or air and oil) to force the caliper piston
against the brake pad which, in turn, is pushed against
the disc. This action slows the rotation of the disc until
the disc stops. Next are some common malfunctions
that may occur in this system and ways that you can
isolate the cause.
Failure to Engage
There are several problems that can cause a brake
to fail to engage. You must understand the operating
principles associated with the system. First, check to
see if there is sufficient air or oil pressure for operation.
It is pretty obvious that if the activating medium (air or
oil) is missing, this condition should produce an alarm
at the console.
Once you determine that the activating medium is
available, you should try the manual control. If the
manual control works, you should consider an electrical
fault as the problem source. If the manual control does
not work, you should continue troubleshooting. If the
pressure regulator is not working, the supply cutout
valve (if installed) may be closed, or there may be a
blockage or leak in the supply line. These are all
possible causes for the failure. The last possibility to
check is the electrical control. Did the brake actually
engage? If the brake engages, but you do not receive a
brake engaged indication, just look at the PT speed to
verify a slowing down or a stop. If the PT has stopped,
your indicator light may be out or the indicator switch
may be bad. If the PT does not stop, you may need help
locating where the command signal is lost.
Failure to Release
When a brake fails to release, the three most
common causes are a command problem, a bad position
indicator switch, or a bad indicator light. If none of
these are the cause, you should check for a binding
caliper and weak or damaged return springs.
Failure to Stop Rotation
When the brake applies but does not stop rotation,
the most common causes are insufficient actuating
pressure, contaminated brake pads, a damaged rotor
(disc), or a binding caliper piston.
ALIGNMENTS AND ADJUSTMENTS
Basically, the only components that have any
adjustments or alignment checks are the PT and shaft
brake systems. Normally, all of these adjustments or
alignments are performed as requirements resulting
from a PMS inspection.
REMOVAL AND REPLACEMENT OF
The removal and replacement of a clutch maybe
performed by your ships personnel if there is sufficient
time or if a casualty occurs. Most of the time, however,
the engineer officer will opt to have an outside activity
perform the work.
On the other hand, the brakes and their subsystems
can be easily maintained by your ships maintenance
technicians and personnel.
LINE SHAFT (SPRING) BEARINGS
The line shaft (spring) bearings are self-aligning,
oil-lubricated journal bearings. Each bearing is a
self-contained assembly with its own oil reservoir that
contains 2190 TEP oil.