TM 1-1500-204-23-11
1
Ensure the thermocouple wire used
warmer than the ambient temper-
is compatible with the temperature
ature, place each thermocouple
monitoring device and the positive
between your ingers and observe
and negative leads are not attached
the temperature rise. If it does not
to the wrong terminals.
respond properly, replace the ther-
mocouple.
Inspect and test all thermocouples for
2
(b) Placement. Thermocouple placement is
continuity. If a thermocouple tester
is not available, use a multimeter to
the key in obtaining proper cure temperatures through-
measure the resistance between the
out the repair. A thermal survey, discussed in para-
two ends on the connector plug; if the
graph 6-18g, can aid in determining the exact location
resistance is greater than 1 ohm (Ω),
for the thermocouples. In general, the thermocouples
repair or replace as necessary.
used for temperature control (control thermocouples)
should be placed as close as possible to the repair
material without causing it to become embedded in the
Inspect the junction for breaks and
3
repair or producing indentations in the repair. They
remove resin buildup before each
should also be placed in strategic hot or cold spot loca-
use.
tions to ensure the materials will be adequately cured
but not exposed to excessively high temperatures
Ensure the thermocouples are com-
4
that could degrade the material structural properties.
patible with the units reading them
Additional thermocouples that monitor temperatures in
(e.g., a type-J thermocouple should
noncritical areas can be placed throughout the repair
be attached to a type-J monitoring
locations; these thermocouples are merely recorded
unit). The monitor should be as close
by the temperature control unit but do not drive the
as practical to the thermocouple. For
application of power to the heat source. See igure
standard 24 gauge wire, the distance
6-39 for typical thermocouple placement. The ther-
shall not exceed 100 feet. Distances
mocouples should be placed as close as possible to
greater than 100 feet can produce
the area that needs to be monitored. The following
incorrect thermocouple readings.
steps should be taken when using thermocouples:
The higher the wire gauge the shorter
the allowed distance.
Plug the thermocouples into the
5
monitor and ensure they read ambi-
ent temperature. If your hands are
6-75