Use; Measurement Procedure; Insulation Measurement - Chauvin Arnoux C.A 6541 Notice De Fonctionnement

4.7.5 Barring of insulation measurement
This function prohibits insulation measurement from being carried out at certain test voltages. This
makes it possible the entrust the instrument to less experienced operators, for specific applications for
example (telephone ...).
6
In SET-UP, press
- The test voltages appear in succession on the small display with the
main display.
- Choose On or OFF using the
access to the insulation tests at these voltages.
5.1

Measurement procedure

I Start up the device by selecting the corresponding position (MΩ, 40 Ω
selector switch. All the segments on the LCD screen are displayed, then the battery (or rechargeable
battery) voltage.
I Connect the leads to the + and – terminals and the points of measurement.
I The input voltage is constantly measured and displayed on the small display.
If an external voltage is present that is greater than the thresholds described in § 5.2, 5.3 and 5.4,
then measurement is prohibited.
I Pressing START/STOP starts measurement.
I Pressing START/STOP once again stops measurement. The last result remains displayed until the
next measurement or turn of the selector switch.
If a voltage > 25 V
AC
voltage on the small display, the warning symbol flashes and the measurement in progress is stopped.
Note : There are several special functions that can be used. (see § 4).
5.2

Insulation measurement

When using this function, the instrument can measure insulation from 1 kΩ to 40 GΩ at a test voltage
of 50 V, 100 V, 250 V and up to 1 TΩ at 500 V and 1000 V.
I Select, with the rotating switch, MΩ-50 V, or MΩ-100 V, or MΩ-500 V, or MΩ-1000 V
I Connect the instrument to the insulator to be tested. If the voltage present exceeds 8 V for MΩ Ω Ω Ω Ω -50
V, or 16 V for MΩ Ω Ω Ω Ω -100 V, or 25 V at all the other test voltages, then measurement is prohibited.
I Start the measurement and read-off the results.
It is possible to scroll through the results on the main display with the R-DAR-PI button, or on the small
display with the V-TIME button (see § 3.2).
Using R (t) when carrying out a 'time-controlled test', it is possible to scroll through the interval
measurement values saved at the sampling rate specified in SET-UP. These samples are available until
another measurement is got underway or the selector switch is turned. (see § 4.3)
When measuring high levels of insulation (> 1 GΩ Ω Ω Ω Ω ), it is advised that the guard terminal should be
used to eliminate the influence of surface leakage currents. The guard is connected, between the two
measurement contact points, to the surface susceptible to surface currents, i.e. dusty or damp cable or
transformer insulation. In this case, croc-clips are preferable to test-probes held in the hand. (see § 11).
As soon as insulation measurement is stopped, the test circuit is automatically discharged over the
instrument's internal resistance.
5 times or more (depending on voltage to be barred):
L
button for each test voltage, to bar (OFF) or to reinstate (On) the
M
or 35 V is detected during all measurements, the instrument indicates this
DC
(see § 3.2)

5. USE

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6
button and On/OFF on the
or 400 kΩ) with the