3. Examples of Test Criteria for Different Transformer Types
3.0 Constructing A Test Program
The test program for a particular transformer can be downloaded from a PC
compatible computer using the Editor and Server Software.
In most programs it is better to perform a resistance test on each
winding first, as this will allow the continuity checks to verify the
fixture wiring as soon as possible.
Following this, tests can be placed in any order required.
However, for some transformers with high permeability cores, it is
possible for the resistance test to leave the cores with residual
magnetism, which will cause a subsequent inductance test to measure a
value that is out of tolerance.In such cases, it is best to perform the
inductance test first.
Alternatively, perform a turns ratio test after the resistance test -
this will demagnetize the core before the inductance test.
When a new transformer type is being tested, it is better initially to
set up the AT SERIES to produce a full report for each test.
After enough transformers have been tested to ensure that sensible limit
values have been programmed for each test, then the report format can be
changed to "failures onlyF which is the normal report format in a