14
Figure 6 Standard mode insulation test
9.2 Insulation resistance testing – timed modes ‘t’, PI and DAR
Three types of timed test are possible:
(a) Standard count down timer (t)
Timed tests are performed over a timed period defined by parameter ‘t’ (also refer to Set-up
procedures 13).
(b) Polarization Index (PI)
PI is the ratio between the insulation resistance values recorded at 1 minute (assigned t1)
and at 10 minutes interval (assigned t2). i.e. after 1 minute and 10 minutes.
PI = 10 minute value/1 minute value
(c) Dielectric Absorption Ratio (DAR)
DAR is the ratio between the insulation resistance values at 30seconds (assigned t1) and at 60
second interval (assigned t2). i.e. after 30seconds and 60seconds.
Symbol displayed
if audible limits
are enabled
M
changes to G
where required
Screen A
Step 6:
Amps, volts and seconds
selection button
Alarm on/off
Step 5:
Press to lock test
Step 8:
Switch off
Step 2:
Select test voltage
Step 3:
Press TEST and hold
Step 7:
Release TEST button
Step 4:
Test result and actual
test voltage
Step 1:
Connect the test leads
Screen B
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