Determining The Polarization Index Ip; Measuring Procedure - LEM ISO plus Manuel D'utilisation

Advanced functions

6.1.1 Determining the Polarization Index Ip

The I value is only available if the insulation test is continued for
p
more than 10 minutes. This again is indicated by a frequence change
of the 5s buzzer alarm. The I
of the insulation. It is calculated using the following formula:
Ι
p

Measuring procedure:

Connect instrument to the installation/equipment with the
supplied test leads.
Select the required Insulation test voltage with the rotary switch.
CAUTION: The installation / test specimen must be set potential-free
prior to measurement!
In case of external voltages above 10% of the selected test voltage
(10V, 25V, 50V and 100V) the measurement is blocked.
Initiate the test by pressing the START key, hold this key down for 10
seconds to activate continuous measurement.
The test can be terminated anytime by pressing „START" again.
(ATTENTION: The measuring voltage is applied all the time!).
While the test is in progress the annunciators
as a warning of the high tension at the measuring terminals.
After a minimum period of 10 minutes indicated by a beep the I
can be displayed using the
The key toggles between R
RISO and the actual measuring voltage UISO.
Measured value evaluation :
I >2.0 means: good insulation and I
p
value gives an indication of the qulaity
p
R (10min)
ISO
=
R (1min)
ISO
ACTIVE
are displayed
key to select the I screen.
p
, I , the latest measured value of
ab p
< 1.5 signifies poor insulation.
p
- 20 -
value
p