MI 3290 Earth Analyser
Technical specifications
141
15.10 Influence of low test current through clamps
In large systems the measured partial current is only a small portion of the test current through the
current clamp. The measuring uncertainty for small currents of and immunity against noise currents
must be considered. The tester displays the “low current icon” warning in this case.
Low test current through Iron or Flex clamps. Results may be impaired.
Limit [ Iron clamps < 1 mA and Flex clamps < 5 mA ].
Measurement function ........................................ Selective (Iron, Flex Clamp), 2 Clamps,
Passive, Pylon Ground Wire Test (PGWT),
Flex and Iron Clamp Meter RMS
Clamps
Additional uncertainty if low current limit is exceeded
Index
Limit
Additional uncertainty
Iron clamp (A1018)
Ic
< 1 mA
(10 % of r 2 digits)
Flex clamp (A1487)
If1, If2, If3, If4
< 5 mA (* See Notes)
(10 % of r 3 digits)
If the low current limit is exceeded by an additional 70 % [Ic < 0,3 mA and If1-4 < 1,5 mA] then the main
measuring result is disabled.
Standard uncertainty Additional uncertainty
Clamp current ≤ Limit Limit -70 %
Test current through clamps Ic, If1, If2, If3, If4
The measuring range of the instrument is exceeded.
Measurement could not be started or displayed!
Notes:
When using only one, two or three flex clamps, always connect one clamp to F1 terminal
(synchronization port).
F1 - Flex clamp 1 input terminal (Synchronization port) is not connected to the
instrument. Always connect one clamp to F1 terminal.
Make sure that the number of turns is correctly entered in the test parameters window.
turns
of
number
0
,
5
limit
4
,
3
,
2
,
1
mA
If
Make sure that the arrow marked on the clamp coupling, points toward the correct orientation
for correct phase measurement.
Negative current through flex clamps; check the right direction
of the Flex clamps [
↑ ↓ ].
Negative current through flex clamps If2 and If4 (
marked with -
).
