Chauvin Arnoux C.A 6454, Руководство пользователя

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64
Display – Indication Remark - Cause
U
P
> U
L
: the measurement is disabled.
Resistance of the auxiliary rod too high: the measurement is
stopped.
Connection of a current probe after selection of measurement
without tripping: the instrument automatically reverts to
measurement with tripping and reports the fact.
During the measurement, U
F
exceeds the value set in the SET-
UP mode: the measurement is stopped.
During a selective measurement, the product of the current
measured by the current probe and the measured voltage is too
low: the measurement is stopped.
During a selective measurement, the current measured by the
current probe is too unstable: the measurement is stopped.
The temperature of the instrument is too high: the measurement
is stopped. Pressing the TEST key has no effect until the
temperature of the instrument is again below 60°C; another
measurement can then be started.
Press the TEST key to exit from the error conditions.
4.3 3-WIRE LOOP MEASUREMENT (
Z LOOP)
4.3.1 DESCRIPTION OF THE FUNCTION
In a TT network, measurement of loop impedance LPE is a rapid and practical way of checking a
earth resistance without planting auxiliary rods. In this case, the measurement includes the
earthing resistance of the power supply transformer of the installation and the resistance of the
distribution cables. It is therefore a high earth measurement, and any error is on the safe side.
In TT and TN networks, this function can also be used to check and size the protective systems in
place by a rapid and easy measurement of the loop impedances between L and PE, L and N, and N
and PE. This function can also be used to calculate the corresponding short-circuit currents (sizing of
fuses and circuit breakers).
Er10
U
P
> 50V
(or)
25V
R
P
> 15 k
Ω Ω Ω Ω
U
P
Er04
U
F
> 50V (or) 25V
Er05
Er06
I = - - - -
> 80°C
HOt