Megger TRAX - TRAX Manual Control Application Examples; Resistance Measurements with Manual Control; Excitation Current Measurements

26 TRAX ZP-AJ01E AJ0383DE
5 OPERATING INSTRUCTIONS
5.3 Manual control
application examples
Important
Read and comply with the safety instruc-
tions “2 Safety” on page 8.
Always comply with local safety regula-
tions.
Note The circuitry for safe discharge of inductive
loads is activated in Manual Control as well
as in the winding resistance app. Discharge is
performed via the current output and the R1/
R2 voltage measurement inputs.
Resistance measurements
1] Press
2] Select a DC current generator 1, 16 or 100A
output (pending the resistance of the test
object. Max resistance is about 10 kΩ when
generating 5 mA from the 1 A generator).
Recommended test current ranges
1 A
generator
5 mA – 1 A Resistance range
1 m – 10 k
16 A
generator
1 A – 16 A Resistance range
160  – 50 
100 A
generator
10 A – 100 A Resistance range
10  – 5 
3] Press
4] Select “R” > “R1” > “DC”
5] Select “Int” > “Gen I” > “DC”.
6] Press “OK”.
7] Press
8] Select resistance calculation “R DC ()” using
“R1” and “Gen I”.
9] Connect current and voltage sense leads to
the test object.
Note This is a 4-wire method. Connect voltage
sense leads “inside” the current leads connec-
tors. The connectors must NOT touch each
other.
10] Select an appropriate test current suitable
for the test object.
Always use as high current as possible but
avoid unintentional heating of the test object.
11] Press
12] Wait for results to stabilize.
13] Press and read the results.
Note Manual Control is not designed for resistance
measurements on inductive loads e.g. trans-
former windings. If Manual Control is used
for this, manual setting with small and slow
adjustment of test current should be used. For
measuring highly inductive loads, e.g. trans-
former windings, the winding resistance app
should be used.
Note For measuring high resistances it is possible to
use a simplified 2-wire technique. Connect the
1A DC outputs directly to the R1 inputs and
connect from R1 inputs to the resistor. Please
observe that maximum compliance voltage is
about 50 V so select a very low current when
measuring in the kΩ range.
Excitation current (impedance)
measurements
1] Select 0-250 V or 0-2200 V generator pending
the expected saturation voltage of the test
object.
2] Select “Gen I” and “Gen U” measurement
channel set to frequency to measure the ex-
citation voltage and current and use the data
for calculations.