18
GMC-I Gossen-Metrawatt GmbH
14.2 Insulation Resistance Measurement
➭
For insulation resistance measurement, press and hold the multi-
function key
FUNC
until the display has stabilized. Insulation resis-
tance measurement is ended when the key is released.
An insulation resistance of less than 1 M
Ω
with a test voltage of
500 V, or less than 2 M
Ω
with a test voltage of 1000 V is indicated
with an acoustic signal.
Automatic measuring range selection is active for insulation resis-
tance measurement. Their is no provision for the manual selection
of the measuring range.
Note!
The instrument’s batteries are rapidly depleted during
insulation resistance measurement. Only press and hold
the mutlifunction key as long as is necessary to take the
reading. Continuous measurement as described below
should only be performed if absolutely necessary.
Use only alkali-manganese batteries in accordance with
IEC 6 LR61.
Continuous Measurement
➭
Activation: Press and hold the multifunction key
FUNC
and simul-
taneously press the
AUTO |MAN
key until acknowledgement is indi-
cated with an acoustic signal.
➭
Deactivation: Briefly press the multifunction key
FUNC
.
14.3 Conclusion of Measurement and Discharging
After the measurement has been completed, any residual voltage is
displayed which may be caused by conductor capacitance.
➭
Discharge the DUT by turning the selector switch to the V
1M
Ω
position. Contact with the DUT must be maintained. The reduc-
tion in voltage can be observed directly at the LCD.
Do not disconnect the DUT until voltage has dropped to below 25 V!
14.4 Evaluation of Measurement Values
In order to assure that insulation resistance does not violate lower
limit values as prescribed by DIN VDE requirements, the instru-
ment’s intrinsic and influence errors must be taken into consider-
ation.
The minimum values for insulation resistance can be determined
with the following table, which must be displayed under consider-
ation of maximum operating error for the METRA HIT 16I/L (under
nominal conditions of use) in order to assure that the required limit
values are not violated.
Limit Value in M
Ω
Min. Display in M
Ω
0.1
0.11
0.2
0.22
0.5
0.55
1
1.1
2
2.2
5
5.5
10
11
20
22
50
55
100
110
200
220
500
550
1000
1100
2000
2200
