TURBINE OVERTEMPERATURE PRO-
TANK LEVEL INDICATOR (TLI)--A
TECTION SYSTEM (TOPS)--A system used to
hydrostatic-type tank gauge, usually operating on
protect a surviving generator from overload in the
the principle of balancing a head of liquid in a
event of another generator failure on a DD or CG
tank against a column of mercury, or on the
class ship.
balanced hydraulic principle employing a float-
actuated remote reading dial gauge. It is used to
monitor the fluid level of a tank.
TURNING GEAR--An electric motor-driven
gear arrangement that slowly rotates idle propul-
sion shafts and main reduction gears.
TEST POINT--A position in a circuit where
instruments can be inserted for test purposes.
UNINTERRUPTIBLE POWER SUPPLY
(UPS) SYSTEM--Critical ship control systems
THERMAL ENERGY--Energy contained in
have a UPS as an emergency power source. The
or derived from heat.
UPS is used to maintain operations during any
interruption of the normal power source.
THERMOCOUPLE-- (1) A bimetallic device
capable of producing an electromotive force
UNIT--A value, quantity, or magnitude in
roughly proportional to temperature differences
terms of which other values, quantities, or
on its hot and cold junction ends. (2) A junction
magnitudes are expressed (for example, yard,
of two dissimilar metals that produces a voltage
pound, gallon).
when heated.
VACUUM-- Pressure less than atmospheric
THERMOCOUPLE PYROMETER--A tem-
pressure.
perature measuring instrument using the change
of electric resistance of a conductor when heated
VALVE-- A mechanism that can be opened
to indicate the temperature being measured.
or closed to control the flow of a liquid,
gas, or vapor from one place to another
THRUST BEARING--Bearings that limit the
place.
axial (longitudinal) movement of the shaft.
VARIABLE STATOR VANE (VSV)--
TOLERANCE-- The allowable deviation
Compressor stator vanes that are mechanically
from a specification or standard.
varied to provide optimum, stall-free compressor
performance over a wide operating range.
TORQUE--A force or combination of forces
that produce or tends to produce a twisting or
VELOCITY-- The rate of motion in a
rotary motion.
particular direction. The velocity of fluid flow is
usually measured in feet per second.
TRANSDUCER-- (1) A device that converts
a mechanical input signal into an electrical out-
VISCOSIMETER-- A device that determines
put signal. (2) Generally, a device that converts
the viscosity of a given sample of oil.
energy from one form into another, always
retaining the characteristic amplitude variations
VISCOSITY-- The internal resistance of a
of the energy converted.
fluid which tends to prevent it from flowing.
TRANSFORMER-- A device composed of
VOLT--The unit of electrical potential.
two or more coils, linked by magnetic lines of
force, used to transfer electrical energy from one
VOLTAGE-- The electric potential difference,
circuit to another. Also, an electrical device used
expressed in volts.
to step up or step down an ac voltage.
VOLTMETER-- An instrument for mea-
TURBINE INLET TEMPERATURE (TIT)--
suring in volts the difference of potential
The GTGS turbine inlet temperature on the
between different points of an electrical cir-
Allison 501-K17. Known as T5.4 for an LM2500
cuit.
GTE.
AI-14