Gossen MetraWatt M 5010 Bedienungsanleitung Seite 32

measured results referred to nominal fault current" and
in Section 4.3.2 "Testing with increasing fault current".
All items listed in these sections likewise apply to
testing of systems with selective fault current circuit
breakers. In addition thereto, note the following:
Selective fault current circuit breakers have a delayed
cut-out action. Due to preloading caused by the
measurement of the contact potential, the cut-out
action is shortly affected (approximately 30 s). To neu-
tralize the preload caused by the Ug measurement, a
waiting time is required prior to making the tripping
test. After operating the sliding switch (7) for the
tripping test, the LC display (1) therefore flashes for
approximately 30 seconds before the tripping test is
made.
Cut-out times up to 500 ms may be measured.
Connection
Measuring Principle
To determine the loop impedance Rsch the M 5010
measures with a test current of 1.0 A. If dangerous
contact potentials (>50V) appear during this
measurement, the tester switches off in the interest of
safety.
The short circuit current lk computed for the nominal
line voltage (230V for the M 5010-02/04, 127V for the
M 5010-03) can be displayed after measurement and
display of the loop impedance.
Measurement
— Set the function switch (2) to "Been".
— Move the sliding switch (7) temporarily to posi-
tion Y. The measuring sequence is started.
Read the loop impedance off the digital measured
value display (24).
Resistance values of up to 1.490 are displayed
with 2 digits behind the decimal point, from 1.50
to 200 with 1 digit behind the decimal point.
When using the measuring adapter (5), deduct its
lead resistance of 0.050 from the measured result.
Particularly note this with small measured results.
If the measured resistance is >200, ,OLQ" is
displayed.
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