DOC. MIE91093 Rev. 1.34
Page 138 of 145
All you have to do is to connect the main AC voltage output to
the CT’s secondary, putting in series the internal current
meter.
1.19.2. Test execution
The test execution is the following one.
Compute the nominal saturation voltage as explained
above.
In the menu, select:
Test control > Save > Manual ESC
Press ON, adjust the first voltage at about 20% of the
nominal saturation voltage; then, press Menu and
Save;
Keep on adjusting and saving with steps that you can
decide, but they will be reduced to 10% and to 5% as
you get close to the nominal voltage knee;
Keep on with small voltage increments, and watch the
absorbed current. When you see it increasing by 50%
when you increment the voltage of 5%, then the knee
has been reached.
SLOWLY REDUCE THE TEST VOLTAGE: if you don’t,
there will be a magnetic remanence which will cause
troubles as you set the CT in service.
Connect to a PC, start the program, download test
results.
On test results, create the following formulas:
. Formula 1: 1.1*Vac;
. Formula 2: 1.5*EXT_I
The test result is the following one.