BD0333JE
ZP-BD03E
MOM2
9
2 INTRODUCTION
2.3 Basic technical
description
The output current is delivered from a supercapacitor
which is charged from the built-in rechargeable bat-
teries.
Kelvin test
The MOM2 uses Kelvin probes or clamps for the
measurement. A Kelvin test uses four wires and meas-
ures continuity resistances ensuring all contact and
lead resistances are compensated for, which allows a
much greater accuracy in measurements. Each Kelvin
probe assembly has two probe tips. When contacting
the test object it will be contacted with two plus two
probe tips. One pair is for the current generated. The
other pair will measure the very small voltage present.
Principle for the 4 wire Kelvin test.
2.4 DualGround – Both
sides grounded
With MOM2 it is possible to make measurements
according to the DualGround™ method. The most im-
portant advantage is improved safety but the method
is also easier and saves time. The number of tasks is
reduced when the ground cable does not need to be
disconnected and reconnected. Permission related
work that may include paper work could many times
be avoided. However, the local safety regulations shall
always be followed.
Using the DualGround method might cause a small
measurement error cause by the current running
through the ground loop. The error value depends on
the relation between the two parallel circuits.
Example
: If the test object is 50 µΩ and ground loop
is 10 mΩ the error will be 0.5%
Two 10 m, 95 mm
2
grounding cables has a resistance
of around 3.6 mΩ. Transitional resistance in connec-
tions and clamps to be added.
With both sides grounded the induced current will not pass
through the test instrument.
www.
.com
1.800.561.8187
