Megger DET3 Series - Just a little aside; Megger gets down to earth with “ART”

Megger Limited PWS / Nov 06
DET4TC/R Launch
16
Just a little aside
The ICLAMP has the ability to measure very small currents, so Megger used this
ability to add yet another benefit. The DET4TC is equipped with an earth leakage
range, allowing quick and easy measurement of leakage current flowing into the
earth system. So if you do need to disconnect an electrode for maintenance there are
no nasty surprises!
Using ICLAMP to
measure electrode
leakage current
Megger gets down to earth with “ART”
So how does ‘ART’ work? The DET4TC will perform the traditional 3 pole
measurements like other earth testers. When in the normal 3P mode the DET4TC
injects a test current at 128Hz (X to C terminals), so as not to clash with the
generation frequency and its harmonics. The voltage measurement is then taken (X
to P terminals) at this frequency, therefore enabling the instrument to ignore other
currents flowing in the earth system. The rest is simply down to ohms law to calculate
the resistance as displayed.
The addition of the ICLAMP now enables only the test current in the individual
electrode to be measured. As with the voltage measurement the ICLAMP measures
the current only at the 128Hz the DET4TC generates, again allowing other currents
flowing to be ignored.
Building earth
connection/s
System leakage current
Ie
Ie Ie
Ie 4 leaka
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DET4TC set to A ran
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