Operation Manual
GMC-I Messtechnik GmbH 47
Measurements R
SL
– MΩ
ISO
@10 V/100 V – CAP Switch positions (a-b) (a-E) (b-E)
6.3.3 Performing Insulation Resistance Measurements
Caution High-Voltage!
Do not touch the conductive ends of the test probes when the
instrument has been activated for the measurement of insula-
tion resistance. If at all possible, only plug in the measurement
cables actually required for this test, because loose test probes
and cable ends represent a contact hazard. You may otherwise
be exposed to a current of 1.5 mA (limited in the measuring
instrument), and although this is not life endangering, the result-
ing electrical shock is quite discernible. If, on the other hand,
measurement is being performed on a capacitive device under
test, for example a cable, it may be charged up to approxi-
mately ±120 V. Touching the device under test after measure-
ment has been performed is life endangering in this case!
Ð Starting the insulation resistance measurement:
Briefly press the UISO ON / OFF key.
Insulation resistance is displayed for the currently selected
conductor pair (analog display is logarithmic).
Ð Reversing polarity of the cable under test:
– Normal polarity reversal:
Press and hold the POL / UISO key.
– Rapid polarity reversal:
Press the POL / U
ISO key at short intervals. bAL.C appears at
the display (ballistic capacitance) for relative cable length
determination. After key activation has ceased for a period
of approximately 2 seconds, the instrument is switched
back to standard insulation resistance measurement.
Ð Switch the rotary selector switch to the MΩ
ISO
_a-b, MΩ
ISO
_a-
E and MΩ
ISO
_b-E positions, one after the other, in order to
execute the desired tests.
000.00
M
Ω
M
Ω
a-b
a-E
b-E
MΩ
ISO
@10V/100V
ISO
a-b
FUNC
ENTER
U
ISO ON
/ OFF
ZERO
ESC
POL / U
ISO
FUNC
ENTER
U
ISO ON
/ OFF
a-E
FUNC
ENTER
U
ISO ON
/ OFF
ZERO
ESC
POL / U
ISO
FUNC
ENTER
U
ISO ON
/ OFF
b-E
FUNC
ENTER
U
ISO ON
/ OFF
ZERO
ESC
POL / U
ISO
FUNC
ENTER
U
ISO ON
/ OFF
U
ISO
000.0
U
ISO
V
FUNC
ENTER
+–
+–
a
a
b
b
E
E
+
–
0V !
Reverse polarity
Discharge
Switch
DC
AC
TRMS
100V
ISO 100V
test voltage on