66
4.1 Troubleshooting
A different
measured value
results each time
the same
measurement
target is
measured.
The differences are due to the effects of the
insulator’s polarity. *
o
Allow an adequate amount of time (about 1
hour to 1 day) to pass after the first
measurement before repeating measurement.
The effects of polarity increase as the insulation
resistance increases.
The differences are due to the effects of the
insulator’s temperature characteristics.
o
Measure the target under the same
temperature and humidity conditions.
In general, an insulator’s insulation resistance
value will decrease as temperature and
humidity increase.
Reference: the insulation resistance value of
some insulated cables decreases to 1/4 or less
when the temperature increases 10°C.
When the
instrument is
calibrated, the
accuracy of the
insulation
resistance range
falls outside the
device
specifications.
The test lead cable insulation resistance is too low.
o
Use the test leads that came with the
instrument or its optional test leads to perform
the calibration procedure. With standard wiring,
characteristics are affected when the
resistance in the 1000 V range reaches or
exceeds 100 M
:
.
o
Replace any test lead with its insulation
performance deteriorated.
The output voltage
polarity is
reversed.
The reversal is due to the characteristics of the
insulation ohmmeter. This does not represent a
malfunction.
There are too few
display digits
(
).
The instrument is set to the mode in which a lower
number of display digits is used.
o
Set the rotary selector to the insulation
resistance range and press
to set the
instrument to the mode in which more display
digits are displayed.
* Polarization: A phenomenon whereby a substance’s positive and
negative electric charges move in opposite directions when an electric
field is applied to it, causing the center position of the positive and
negative charges to shift.
Symptom
Check Items
IR4052
www.
.com
1.800.561.8187
