LumaSense Technologies LumaSHIELD Controller Installation Guide: Winding Temp. Sensors - Manual (Page 2)

Installing a Standard Sensor
This section gives some advice for installing a standard
sensor (without the optional mounting disk) into a key
spacer.
The customer must prepare his own key spacers for install-
ing the fiber optic sensor. A groove and two openings
have to be made in the spacer. Figure 6 shows the recom-
mended groove.
LumaSense fiber optic protection tube has tiny venting
holes to let air escape and let oil in. A first hole is located
38mm from the tip of the sensor. Do not let adhesive go
into the hole: the hard adhesive can transfer too much
stress on the optical fiber.
Do not let adhesive go onto the tip either: during coil
compression, a hard adhesive will transfer directly the
pressure from the coil to the sensor tip. Make sure the
sensor tip is snug but free to move inside the groove.
Referring to Figure 6: the glue will spread along the
groove by capillarity. Drill two holes approx 4-5 mm to
stop the capillary action and to keep the glue from reach-
ing either the tip or the first hole.
The groove is kept tight at the tip to maximize heat trans-
fer.
The angle of the groove is chosen to ensure a smooth
egress of the fiber optic cable so that there is no sharp
turn in the fibre cable (minimum bending radius is 25 mm
for 62.5 / 125 μm fiber).
Do not let the sensor tip be crushed when compressing
the coil. Minimum spacer thickness is 1.5 mm to give head-
room for the 1.2 mm O.D. sensor tip. Example : for a 15 %
coil compression ratio, using 1.6 mm thick spacer and the
1.2 mm O.D. sensor tip, the maximum allowable compres-
sion is (1.6 – 1.2) ÷ 1.6 = 25 % which gives some tolerance
to local variations and irregularities.
Installing a Sensor Equipped
with Optional Mounting Disk
As an option to the regular sensor, LumaSense can provide
sensors with a factory-installed mounting disc at 12mm
from the sensor tip.
Figure 6: Specifications to user for grooving a key spacer
for a standard sensor.
Figure 7: Tube venting hole.
Figure 8: Example of a grooved key spacer.
Figure 4: Typical TC connector installation.
Figure 5: Internal extension cable routing.
Figure 3: Sensor installation.