12
GOSSEN-METRAWATT
Starting the measurement
Attention!
!
An insulation measurement is blocked when a
voltage > 25 V is applied to the probes prior to
starting the measurement! A short sound signal
points to this.
í
Press the measurement pushbutton (8) in the probe and
hold it at this position.
The display switches to ISO-
Ω
measurement with the fol-
lowing presentation:
Digital display
: In line with the measured value, the tester
selects that measuring range from the 6 automatically
selectable ISO-
Ω
measuring ranges with which the best
resolution is obtained. When the measured value changes,
it automatically switches:
– to the next higher range at 3199 1 digit
– to the next lower range at 300 digits –1 digit
Overrange „OL“ is signalled, when the meas. value is higher
than 3 G
Ω
. You can measure insulation resistances up to
30 G
Ω
after manual range selection acc. to section 7.4!
Analog indication
: The entire measuring span of the ISO-
Ω
measurement (all of the 6 automatically selectable measur-
ing ranges) is shown on the analog scale in logarithmic
scale in coherent form. This makes for changes in meas-
ured value to be quickly detected and observed over sev-
eral measuring ranges. With measured values below 3 k
Ω
,
a triangle is shown at the left end of the analog scale in
place of the pointer. With a measured value of more than
3 G
Ω
, overrange is signalled by a triangle at the right end of
the scale. You can measure insulation resistances up to
30 G
Ω
after manual range selection according to section
7.2!
Lamp in the probe (9)
: The lamp functions as long as you
press the pushbutton in the probe. It illuminates the meas-
uring point when the measured insulation resistance is
> approx. 500 k
Ω
on the nominal voltage range 250 V,
> approx. 1 M
Ω
on the nominal voltage range 500 V and
> approx. 2 M
Ω
at a nominal voltage of 1000 V. The lamp
does not light with measured values that are smaller than
the given values.
It thus serves for a quick Good-Bad judgement of the insu-
lation resistance. As long as the lamp lights, the minimum
indication values of the insulation resistance according to
DIN VDE 0100 are definitely not fallen below.
You can switch the lamp on to illuminate the measuring
point even if the insulation resistance is lower than the val-
ues given for the lamp switching point.
Press the „AUTO/
⊗
“ pushbutton (2). The lamp lights as
long as you keep the pushbutton pressed.
Sound signal
: Insulation resistances < 2 k
Ω
are reported by a
sound signal which ceases at values > 6 k
Ω
.