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Model TD50 / LS

Tan Delta and Dielectric Constant of
Insulating Materials

  • Dissipation Factor (tg d) of transformer oil and others insulating liquids and solids
  • Dielectric constant of liquid and solid insulating materials
  • Can be supplied with test cells according to IEC 247 and ASTM D 924 standards
  • For laboratory use or to perform sample tests in the field


  • Capacity and Dissipation Factor Bridge, Power Supply and Standard Capacitor as a whole system in a single cabinet
  • Direct reading of capacity and dissipation factor with digital display 
  • High accuracy and resolution, can be used for type tests of transformer oil
  • High resolution also with low voltage
  • Transformer - Ratio Bridge guarantees long term stability
  • Tests are performed at industrial frequency (50 or 60 Hz)
  • All cable connections are at the rear panel


CONIMED Model TD50 / LS is an integrated system to perform tan delta tests on insulating materials like transformer oil.

The test cell supplied fulfills requirements of Standards IEC 247 and 250, and ASTM D924 and D150. The test cell is normally used together with the digitally controlled thermostatic bath Model TB110, that allows tests to be performed from ambient temperature up to 110 șC.

Modern transformer oils can exhibit a dissipation factor as low as 0.04 %. That is the reason that it is used a three terminal type test cell, and the whole system must be capable to measure low capacities at low voltage with high resolution and accuracy.

The test voltage can be adjusted between 0 and 1000 V when the test object capacity is below 1000 pF. The oil test cell capacity is around 76 pF in air.

Only 40 ml of oil are needed from each sample. The test system can be use in the field to measure tan delta while oil is being treated.


Ranges: 1.000 pF - 10.000 pF
0,01 % of range
Fine adjustment up to 0,0001 %
± (0,1 % of range + 0,2 % of reading)

Dissipation Factor
Ranges: 1 % - 10 % - 100 %
Resolution: 0,001 %
± (2 % of reading + 4 x 10 -5)

Test Voltage
0 - 1.000 V in the range of 1.000 pF
0 - 100 V in the range of 10.000 pF

Null Detector
Voltmeter for test voltage

TD50 /LS - A: 220 V - 50 Hz
TD50 /LS - B: 110 V - 60 Hz


Three terminal type according to IEC 247 / ASTM D 924
Electrodes: of stainless steel
Insulating supports: PTFE
Design: conic, this allows to keep alignment independent of temperature
Capacity: without oil around 76 pF
Oil capacity: around 40 ml
Test voltage:
Empty: up to 500 V
With oil: up to 2.000 V


Temperature range: ambient up to 110 șC
Temp sensor: PT100
Operator electric shock protected


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