B) Current Measuring "A - VOLTCRAFT VC-540 Operating Instructions Manual

b) Current measuring "a"

Do not exceed the maximum permitted input values. Do not touch any circuits
or parts of circuits if they may be subject to voltages higher than 33 V/aCrms
or 70 V/DC! Danger to life!
The maximum permissible voltage in the measuring circuit against ground
potential must not exceed 600 V in CaT III.
observe the required safety notes, provisions and safety measures for
intrinsic protection.
The current measurement takes place contact-free via the unfoldable current probe (1).
The sensors in the current probe record the magnetic field that is surrounded by conductors
through which current flows. A measurement is permitted on insulated as well as uninsulated
conductors and current rails. Ensure that the conductor always runs through the current probe
centred and that the probe is always closed.
Always hold only one conductor with the current injection probe. If both the supply and
return conductors (e.g. L and N or plus and minus) are recorded, the currents will cancel
each other out and you will not get any measuring result. If several outer conductors
are recorded (e.g. L1 and L2 or plus conductor 1 and plus conductor 2), the currents will
add up.
At very low currents, the insulated conductor can be coiled
several times around a shank of the current probe to
increase the overall measuring current. Then divide the
measured current value by the number of coils around the
current probe. You will then receive the correct current value.
Proceed as follows to measure direct currents (a, ma
- Switch on the DMM with the dial switch (14) and select the matching measuring range.
- At measurements from 0 to 5000 mA (5 A), select the range "mA
for direct current "DC" now appear in the display.
- At measurements from 5 to 80 A, select the range "A
rent "DC" now appear in the display.
- Due to the high sensitivity and the ambient magnetic field (e.g. magnetic field of the earth,
etc.), a low current value is always displayed with the current probe closed. The display must
be manually set to zero right before each measurement or when the current cable is replaced.
):
". "mA" and the symbol
". "A" and the symbol for direct cur-
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