User manual

GMC-I Messtechnik GmbH 15
6 Measuring Insulation Resistance
Select Measuring Function
➭ Select the R
INS
measuring function with the rotary switch and,
depending on the measuring task, constant or variable test
voltage (Uvar), or a ramp function (Uramp).
Connection
Note
Checking Measurement Cables Before Measurements
Before performing insulation measurement, the test
probes on the measurement cables should be short-cir-
cuited in order to assure that the instrument displays a
value of less than 1 kΩ (see section 9). In this way, incor-
rect connection can be avoided and broken measure-
ment cables can be detected.
➭ Connect the device under test to the + and COM jacks.
Sample connection layouts for insulation resistance measurement
are included in section 13.1.
Insulation resistance can only be measured at voltage-free
objects. If mains voltage or interference voltage is applied to the
measurement inputs, measurement cannot be started.
Semiautomatic Measurement in Multipole Systems
Fast, semiautomatic polarity reversal is possible in all rotary switch
positions for insulation resistance measurement. However, polar-
ity selection is only relevant for documentation.
Fast Polarity Reversal
The polarity parameter is set to AUTO1 (single-phase mains volt-
age) or AUTO3 (3-phase mains voltage).
There are two ways to quickly and conveniently switch amongst
all polarity variants without switching to the parameter settings
submenu:
• Press the NEXT key.
• Press the save key at the instrument twice after each mea-
surement.
Continuous Measurement via the CONTIN. Key
Note
The instrument’s batteries are rapidly depleted during the
insulation resistance measurement. Stop continuous
measurement with “constant test voltage” as soon as the
display has settled in.
R
INS
U
var
U
ramp
HELP
1/2
2/2
L-PE
N-PE
1/4
2/4
3/4
4/4
L1-PE
L2-PE
L3-PE
N-PE
AUTO1 AUTO3
R
ISO
/R
INS
→ MEMORY
MEMORY → R
ISO
/R
INS
Switch
and save
Switch
without saving
NEXT