Megger MFT1741, User Manual

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User Guide Addendum -
MFT1741-MFT1845
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During a test the analogue arc will reduce as the degree of
confidence in the measurement increases. As the influence of
electrical noise on the measurement is removed the analogue
arc reduces down to one element. At this point the test stops and
a final result is shown.
The arc may fluctuate during a test and the shown digital value
will change as the Confidence Meter analyses the electrical noise
and corrects the value.
3Lo Loop Impedance Measurement
Note: Test leads should not be disconnected during a test, as the
sudden interruption of the test current could be detected by an
RCD as a leakage fault and cause a trip. If this is considered to
be potentially inconvenient or hazardous, change 3Lo from AC/A
to B mode. This will reduce the risk of the RCD tripping.
Important : It is impossible to guarantee that an RCD will not
trip as the RCD may be out of specification, subject to additional
external influences, incorrectly connected or faulty. In this
instance alternative methods to test the circuit characteristics are
recommended, for example, the R2 method.
1. Select L-PE .
2. Connect the Live, Neural and Earth test leads of the
MFT to a live circuit. The display will show the standard
warning screen.
Figure 2. Analogue Arc
Initial value Start Analysing noise Finished