Amprobe MEGATEST-5000 Megohmmeter - Manual (Page 20)

This measuring method, based on resistance ratios, gives a dimensionless result,
independent on a series of factors such us equipment size, temperature or environmental
conditions.
Insulator status 60/30 sec ratio Polarization index
10/1 min ratio
dangerous ─── less than 1
questionable 1.0 ч 1.25 1.0 ч 2
good 1.4 ч 1.6 2 ч 4
excellent more than 1.6 more than 4
Tab. 1: Insulator status as revealed by the polarization index.
The measurement of the polarization index of a dielectric can be taken by manufacturers
of electrical equipment to test, for example, materials to be used for the production of
supports for conductors, components and devices, insulation of motor coils.
KEY OPERATION
Ш Ч Reach the memory cell P20. PI is displayed.
SeT
The V2 parameter indicator is flashing.
Ш Ч Set the desired V2 voltage value (test voltage) between 100 and 5000V. The
top secondary display will show the value you are setting.
SeT
The T2 parameter indicator is flashing.
SeT
Leave the programming phase. The flashing measuring mode TIMER
advises that you can save the settings.
SavE
Save the parameters in the location previously selected (if requested).
StarT
The message “go?” is displayed.
StarT
The measurement is started.
• The test can be interrupted at any time (provided that at least 75 seconds have passed
from starting).
• At the end of the measurement the PI value is displayed. Press MODE to display the
last resistance value measured.
• Press SAVE to store the measured values.
• It’s possible to recall the measured values. Press SET/EXIT to run over the PI values,
the resistance values and the measuring parameters.
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