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NEPTUNE
EN - 20
6. Insert the red lead into input terminal
V
/+
and the black lead into input terminal
COM/
and possible alligator clips, and connect the instrument to the system to be
tested (see Fig. 19).
7. Press key
GO/HOLD
to activate the test. The screen in Fig. 17 may appear on the
display to signal the presence of a voltage
>10V
found on the input terminals,
preventing the test to be carried out.
8. In case no anomalous conditions are found, the instrument performs the test in a
continuous mode with a countdown of time (until time
“
0:00
”
) for the entire duration of
the set timer, symbol flashes on the display and the buzzer gives out an intermittent
sound. At the end of the test, the following screens appear on the display.
Fig. 21: Results of insulation measurement in TMR mode
9. In the screen in Fig. 21
–
left side, the value of insulation resistance is present (symbol
“
>1999
”
indicates the out-of-range condition) at the end of measurement with positive
result
“
OK
”
(value higher than the set threshold). In the screen in Fig. 21
–
right side, the
value of insulation resistance is present at the end of measurement with negative result
“
NOT OK
”
(value lower than the set threshold).
10. Press keys
/
or
/ZERO
to display the real applied voltage.
PI mode
The PI mode is used to carry out diagnostic duration tests on materials (appliances,
electric cables, etc.) in order to evaluate the quality of insulation. The purpose is the
evaluation of the following coefficients:
Polarization Index (PI) defined as:
min)
1
(
min)
10
(
Riso
Riso
PI
Dielectric Absorption Ratio (DAR) defined as:
)
30
(
min)
1
(
s
Riso
Riso
DAR
See § 9.2.1 and § 9.2.2 for further details.
CAUTION
Check that the circuit being tested is not live and that all possible loads
normally connected to it are disconnected before carrying out insulation
measurement.
We recommend holding the alligator clip respecting the safety area created
by the hand protection.