LumaSMART
®
User Manual
Installation of Probes and Accessories
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35
3.4.1
Sensor Installation Guidelines
Install the temperature sensor during transformer construction or the rebuilding phase, when there is access to
the optimum location.
Situate the probe tip in the desired area inside the transformer. The probe installation portion of the assembly is
normally selected to allow the connector end to be tangentially brought out of the windings, with sharp bends
kept to a minimum, to a point where the sensor is accessible when the assembly is complete. Dirt on the fiber
connector reduces the optical signal level; therefore, tape the connector end over or cover during the remainder
of the transformer assembly operation. This can be accomplished by leaving the yellow Teflon cap provided with
the probe in place.
Caution:
To avoid problems, wherever possible, route the probe fibers to follow equipotential paths
or to at least not cut directly across potential gradients.
Sensor Tip Placement
In core form transformers, the probe tip is typically installed in the winding spacer next to the winding conductor
in the hottest region of the winding, as determined by the transformer manufacturer (usually, the third or fourth
coil from the top in the low voltage winding).
Ruggedized Fiber Optic Probe Installed at the Low Voltage Winding Hottest Spot
(Core Form Transformer)
In core form transformers, the probe tip is taped directly onto the winding conductor in the hottest region of the
winding as determined by the transformer manufacturer. A similar method can also be used in shell form
transformers.
3.4.2
Installing Probe Tip in a Core Form Transformer
If a core form transformer probe-tip installation is required, use the following installation procedure.
The most secure method of positioning the sensor is to secure the fiber optic probe tip in a modified radial spacer.
In this method, the probe tip lies in a cavity formed within the radial spacer. The tip measures the oil temperature
