Loop Resistance Measurement - BEHA UNITEST TELARIS 0100 Bedienungsanleitung

" Connect 3 pole test leads to instrument.
" Only connect the U+ and U- plugs to the UUT via
the alligator clamps. The PE connection should
not be connected; otherwise, the TELARIS 0100
cannot perform correct measurements and dis-
plays 0.00 MΩ.
" Select insulation resistance measurement
range (RINS) via the rotary switch.
" To start automatic measurements, briefly press
the "Start" key (25). If a continuous measure-
ment should be carried out, keep the "Start" key
(25) depressed until the desired end of the mea-
surement.
During the test, the instrument continuously
indicates in the lower display part the nominal
voltage (500V) of the insulation measurement
range.
" Read the measurement value on the display.
During the measurement process, intermedia-
te results are displayed. The continuous mea-
surement should be carried out until final mea-
surement value stabilisation.
If the automatic measurement takes a long time
(approx. 10s), then the UUT has a high capaci-
ty value. In this case, you should carry out a
continuous measurement, as the automatic
measurement should be interrupted after 10s.
Possibly, the correct final value has not yet sta-
bilised.
You may even enter continuous measurement if the
instrument program is set to automatic measure-
ment by pressing the "Start" key (25) and keeping it
depressed.
During the measurement, the instrument con-
tinuously shows the nominal voltage (500 V)
of the insulation measurement function in the
lower display part.
36
Loop Impedance Measurement
If „>199.9 MΩ" appears on the display, a par-
ticularly good insulation resistance has been
measured.
Possibility to store the measurement result by
pressing the key „Store" (26).
5.3 Loop Impedance Measurement /
Prospektive Short-Circuit Current
Measurement
The loop impedance (L-PE / loop impedance) is un-
derstood as the sum of all resistance values within
a current loop, consisting of the resistors of the cur-
rent source, the external conductor of the current
source up to the measurement point and the return
line (PE conductor) and the other current source
pole. The measurement determines the loop im-
pedance between the external conductor and the PE
conductor. The loop impedance value is measured
by short-term mains loading. With the instrument
the TELARIS 0100, short-circuit current is deter-
mined by calculation. The short-circuit current must
be known such that an excess current release hav-
ing been switched in series can trigger at an appro-
priate current level and thus at sufficient speed in
the event of a short-circuit.
To obtain precise measurement results, switch
off all loads or disconnect them from the mains.
Prior to any loop impedance measurement, en-
sure that any RCDs are bridged.
Only the calibrated test lead which are in scope
of supply must be used!