Operation Manual

MI 3121H Smartec 2,5 kV Insulation / Continuity Insulation resistance
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Figure 5.5: DAR result displayed during
measurement (result flashing)
Figure 5.6: PI result displayed during
measurement (result flashing)
After measurement is finished it is possible to switch between DAR, PI, also R60 and
insulation results. R60 is the resistance value measured 1minute (60 seconds) after start
of the measurement.
Simply keep pressing (few seconds) the TAB key to enter to the sub results menu. Here
you can list sub results (DAR, PI, and R60) with normal pressing on the TAB key.
Automatically turn back from sub result menu is occurred, after all sub results are
displayed once. See the Figure 5.7, Figure 5.8 and Figure 5.9.
Figure 5.7: DAR result
displayed after measurement
Figure 5.8: PI result
displayed after measurement
Figure 5.9: R60 value
displayed after measurement
For additional information regarding PI and DAR diagnostic, please refer to Metrel’s
handbook Modern Insulation Testing.
5.1.3 Guard terminal
The purpose of the GUARD terminal is to lead away potential leakage currents (e.g.
surface currents), which are not a result of the measured insulation material itself but of
the surface contamination and moisture. This current interferes with the measurement i.e.
the Insulation Resistance result is influenced by this current. The GUARD terminal is
internally connected to the same potential as the negative test terminal (black one). The
GUARD test alligator should be connected to measured object so as to collect most of the
unwanted leakage current, see the figure below.