16
PM1A
=
Polarization Index
The key makes it possible to visualize the PI value on the display. For
this type of test, the equipment must be connected and apply voltage to
the sample for 10 min. After this period, the operator must press the key
to display the PI value.
The Polarization Index is the ratio between the insulation resistance value measured
after10 min.and the value measured after 1 min.
IP R
10 min
R
1 min
The Polarization Index is useful to determine whether it is necessary
to perform predictive maintenance in order to detect any insulation
resistance wear and tear due to the excess of dust, dirt, grease, or
else the action of chemical or physical agents, etc.
If the key is pressed before the 10-minute period has elapsed,
the key will show
