Voltech AT360, User Manual

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3-49
d. Insulation resistance
To detect poor interwinding isolation where safety is not an issue,
for example between two secondary windings.
e. Safety tests such as hi-pot
Available only on the Voltech AT3600, Hi-Pot must be used to
detect poor interwinding isolation where safety is an issue. For
example, from a primary winding to a secondary winding on a mains
isolation transformer.
For iron cored transformers operating at the 50 or 60Hz line
frequency, where normal operation extends to the point of core
saturation, magnetizing current and open circuit voltage
measurement are normally the preferred tests. These tests are
available only on the Voltech AT3600.
3. Use test limits that are as wide as possible.
For example, if you are testing the turns ratio between windings where
the actual number of turns on one of the windings is only 10, specify
limits of
±
5% (which is equivalent to half a turn).
4. Make use of the Measure button.
For many tests, the dialogue box for the test contains a button labeled
‘Measure’.
If, when you are creating your test program, you have a tester
connected to your PC, fitted with the appropriate test fixture containing
a specimen transformer, clicking on the Measure button will signal the
tester to measure the actual parameter of the test. The result will be
returned to the PC, and the Editor will insert it as the ‘nominal value’ in
the limits section of the test dialogue box.
This is often the best way to find the value for some of the parameters
which you may wish to test, but which do not appear on the actual
transformer design documents.
5. Finally, download and run the program from the Editor and make sure
the results are what you expect before you use it in production.