Pre-Use Checks - Iso-Tech IIT-2301 Bedienungsanleitung

When used as an insulation tester, the instrument is configured
to measure high values of resistance and hence the electrical
quality of the insulating material within the circuit. The
insulation tester applies a high voltage, measures the total
leakage current flow and displays the calculated resistance.
A DC voltage is used to eliminate leakage currents caused
by capacitance in the circuit. A steady insulation resistance
reading will indicate that any capacitance within the system is
fully charged and the capacitive leakage current has reduced
to zero. Insulation resistance measurement errors may be due
to the circuit under test being wet and/or dirty. Errors may
also occur when testing large installations where the insulation
resistances may effectively be in parallel.
All fuses in or circuit
breakers closed
Mains Switch Open
Main
switch
open
Typical arrangement for insulation testing.
 Warning! Verify the circuit is de-energised before
testing.
Equipment disconnected
Switches
Lamps out
closed
Reading not less than
0.5 MΩ

5 Pre-use checks:

 Caution! Before connecting to the circuit to be tested,
carry out the following checks;
5-1 Meter zero check:
Ensure the instrument is turned off and check the pointer
aligns with the ∞ (infinity) mark on the red megaohm scale. If
not, rotate the zero adjustment screw with a small screwdriver
until the pointer aligns correctly.
5-2 Battery Check
When the battery voltage falls below 6.5V, the instrument will
not give reliable or accurate indications. Use the battery-check
function to check there is sufficient energy in the battery before
beginning tests.
a) Remove the instrument leads.
b) Set the function selector switch to BATT check and press
the test button.
c) Check the pointer moves to the "BATT good" sector of the
scale; if not, replace the batteries.
5-3 Test Leads Check
Connect the test leads to the instrument, switch to the Ω x
1 function and press and turn the test button to lock it down.
Connect the leads together and ensure the pointer moves from
the oo position towards the 0 position on the green "Ohms"
scale. If not, the leads may be open circuit or the fuse may
have blown; check and rectify the cause before proceeding
further. If the pointer moves towards the 0 position on the
green "Ohms" scale, check it settles accurately at the 0 mark.
If not, adjust the ohms zero knob to set the pointer accurately
to the 0 mark. Release the test button after the check is
complete.
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