Note: There is a short delay
on the first operation of
‘1000V’ range, each
time the range is
selected. This is to
prevent accidental
application of 1kV.
The M
Ω
range features a
leakage current display.
Leakage current is the value
of current that flows during
the insulation test. To view
the leakage current press the
key. To view insulation resistance press the key
again.
Good Procedure Whilst Insulation Testing
Care must be taken when taking measurements greater than a
few G
Ω
. The leads must be clean dry and in good condition.
They must also not be allowed to tangle. It is also advisable
that the switched probe SP1 is not used as the accuracy at
high value measurements is not guaranteed. The instrument
should also be clean and dry with particular attention paid to
the terminals. Also attempt to reduce any leakage that may
give erroneous results on the item under test.
Polarisation Index Testing
Polarisation Index (PI) is the term applied to the Dielectric
Absorption Ratio when resistance values are measured after
1 minute and again after 10 minutes. Polarization Index is then
the resistance value after 10 minutes divided by the resistance
value after 1 minute. The test can be run at any voltage. More
detailed information on PI Testing and value assessment can
be found in Megger Limited publications listed in the
Accessories page.
Automatic Discharge
When the TEST button is released after an insulation test (or
re-pressed if
ltb feature is enabled), a 200k
Ω
load is
automatically switched across the terminals to discharge the
item under test. Any voltage present will be indicated on the
display so that the discharge can be monitored.
TYPICAL TERMINAL VOLTAGE CHARACTERISTICS
FIG.1
50V - 1000V Ranges
10V Range
