GOSSEN-METRAWATT
17
7.4
ISO-
Ω
measurement up to 30 G
Ω
You can measure insulation resistances on the 30 G
Ω
measuring range only at a nominal voltage of 500 V or
1000 V and after manual range selection.
í
Procede first as described in section „7.2 ISO-
Ω
meas-
urement up to 3 G
Ω
with manual range selection“.
í
Then select the highest measuring range 30 G
Ω
with the
„RANGE
↑
“ pushbutton (3).
í
Make a solid connection of the test leads to the device
under test using the included alligator clips and make
sure the test leads do not touch each other. It is of
advantage to run the test leads to the device under test
as „free leads“. You can thus prevent the parallel insula-
tion resistance of the test leads from affecting the meas-
ured result.
í
Start the measurement by briefly pressing the measure-
ment pushbutton „ “ (1).
This also is a measure to prevent the measured result
from being affected by touching of the probes.
í
When the LCD display (5) shows „DATA“ and a brief
sound signal draws your attention to this, you can end
the measurement by again pressing the pushbutton „ “
(1), read and hold the measured value (see „Holding the
measured value“ in section 7.1).
8
Measuring low-ohmic resistances (0 ... 30
Ω
)
8.1
Measuring with automatic polarity reversal
Attention!
!
Verify that the device under test is electrically
dead, e.g. by means of a voltage measurement,
before you perform measurements on the low-
ohmic measuring range. The fuse blows, when a
voltage source of a sufficiently high energy yield is
connected!
í
Set the rotary switch (6) to the „
Ω
“ position.
The LCD display (5) only shows the decimal point
together with the number 30 and the unit
Ω
. The analog
scale is blanked.
í
Start measuring by briefly pressing the measurement
pushbutton (8) in the probe (9) or the pushbutton (1).
„CONTINUOUSLY ON“ with the measurement pushbut-
ton „ “ (1) is not possible when measuring with auto-
matic polarity reversal. The tester now automatically
measures first in one direction of the current and then in
the other. The LCD display first shows the arrow at the
left and then the arrow at the right of the „
Ω
“ character.
The right arrow signals a direction of the current from „+“