Operation Manual

40 GMC-I Messtechnik GmbH
Measurements: V/Hz – R
SL
– Ω – – Temp – – m – M Ω
ISO
– A/Hz
5.8.1 Connecting the Measurement Cables
Note
Testing the Measurement Cables
The test probes at the ends of the measurement cables
should be short circuited before performing insulation
resistance measurements with the selector switch in the Ω
or the position, in order to make sure that a value close
to 0 Ω is displayed at the instrument. Incorrect connection or
a broken measurement cable can be detected in this way.
Ð Cable connection:
Connect the measurement cables to jacks a, b and E.
5.8.2 Detection of Interference Voltages
Ð Set the rotary switch to the a-b, a-E and b-E positions, one
after the other, in order to display any interference voltage for
all three conductor pairs.
Note
Insulation resistance may only be measured at voltage-free
devices.
5.8.3 Performing Insulation Resistance Measurements
Caution High-Voltage!
Do not touch the conductive ends of the test probes when the instru-
ment has been activated for the measurement of
insulation resistance. If at all possible, only plug in the measure-
ment 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 resulting electrical shock is quite discernible. If,
on the other hand, measurement is being performed on a capaci-
tive device under test, for example a cable, it may be charged up
to approximately
± 120 V. Touching the device under test after
measurement has been performed is life endangering in this case!
COM mA A
V
Tem p
Ω
aEb
00 . 00
Ω
Short circuit the measurement cables.
a
a
b
b
E
E
R
x
0V !
!
ab
aE
Eb
a-b
a-E
b-E
MΩ
iso
at 100 V
UISO
Interference Voltage Detection
000.0
UISO
V
DC
AC
TRMS
iso