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This method permits an accurate determination ob
above quantities at ambient temperature. The Conductivity
Meter For Liquids LCM-8716 is an easy to use instrument composed of a
portable measuring device and a compact low loss test cell. Quality
Assessment of Dielectric Liquids
According to Ohm's law, the volume conductivity 
is a scalar quantity, which relates an applied electric field
strength to a material with the generated conduction current density
through it. For an homogeneous material and particularly for a liquid
subjected to a low electric field, the volume conductivity is
constant throughout its volume and it depends on the properties of
the liquid material itself and on those of the contained ionisable
substances (ionic impurities). Therefore a liquid can well be
characterised by its volume conductivity. The
alternate square wave method (low voltage low frequency) according to
IEC 61620 standard is an adequate method to determine the volume
conductivity and the
relative permittivity 
of insulating liquids at low temperature without disturbing their
thermodynamic equilibrium.
For insulating liquids used in electrical power
apparatus, the conduction is the sole cause of loss at power
frequencies (50/60 HZ), which are low frequencies indeed. Therefore,
the dissipation factor tan
calculated from the measured
and with the alternate
square wave method is equal to the value of tan
measured with the classic bridge method.
The Conductivity Meter For Liquids LCM-8716 works
with the low voltage alternate square wave method and satisfies all
the recommendations of IEC 61620 standard:
"Insulating liquids
- Determination of the dielectric dissipation factor by measurement
of the conductance
and capacitance
- Test method"
first edition, dated 1998-11.
The Conductivity Meter For Liquids LCM-8716 can be supplemented with a Test Cell Heater LCM-8716-H and
diverse Test Cells can be supplied on request.
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