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TST – for transfomer applications



Fiber Optic Temperature Sensor

The TST probe is a robust, oil-permeable fiber optic sensor for monitoring temperature and “hot spots” inside oil-filled power transformers. The product is especially useful for monitoring transformer performance in manufacturing as well as over the product lifecycle. Over time, transformer temperature and performance can be influenced by oil breakdown as well as vibration.

The TS Trafo probe is completely passive and non-conductive. The innovative construction provides perfect protection against dielectric oils and other liquids, as well as prevents build-up of bubbles.

These sensors are easily installed and spacer-mounted directly on the transformer windings. In addition, a special optic feedthrough SINGLE-FT is available for installation on tank walls and transformer housing.

These innovative, passive sensors are completely completely immune to RFI, EMI, NMR and microwave radiation. The probes are also entirely inherently safe as they do not contain any components which could create sparks lead to explosions.


Name of sensor TST, the comprehensive one
Sensor Type GaAs
Temperature range -200°C to +200°C
Accuracy +/- 0.2°C
Thermal response Up to 19°C/s
Fiber Ø 200/220/240μm
Sensor length

2m standard

Other lengths on customer request, max 20m.

Connector type ST
Signal conditioner Compatible with all FOTEMP and INSULOGIX series fiber optic thermometers

Specifications subject to change without notice

Ordering Information

TST2J-XX For use with J-Spacer
XX=Overall Sensor Length in meters, max length 20m
TST2D-XX For use with Disk
XX=Overall Sensor Length in meters, max length 20m
DIST-CXXX-XX          FO Extension Cables, Standard Lengths=3m, 5m, 10m
Special lengths up to 100m available upon request
FOTEMP1-H-A Standard 1-Channel Handheld Signal Conditioner, RS232,
A-Calibration= -40C to +200C,
IN STOCK – Rent or Purchase
FOTEMP4-P0-V-B Standard 4-Channel Bench Top Signal Conditioner, USB/RS232,
0-10V Analog Output, B-Calibration= -40C to +300C,
IN STOCK -Rent or Purchase
Standard 8-Channel Chassis or DIN Rail Mount Signal Conditioner, 4-20mA Analog Output, A-Calibration= -40C to +200C
P1 Interface Option=RS485/Modbus RTU and USB
P2 Interface Option=Ethernet/Modbus TCP and USB
# of Channels= 4/8/12/16 Channels available upon request


  • Temperature range: -200°C to +200°C
  • High Accuracy: +/- 0.2°C
  • Completely non-conductive, inherently safe
  • Immune to RFI, EMI, NMR and microwave radiation
  • Precise, direct temperature measurement
  • Monitoring of the transformer temperature
  • Extends transformer lifetime
  • Easy and quick installation
  • Long-term reliability


  • Generators
  • Oil-filled transformers
  • Monitoring of “Hot-Spot” inside transformers
  • Measurement in gas insolated power breakers
  • Temperature measurement on large drives


Call +1-805-389-6600 or email

Credit Card Orders Accepted

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