Voltech AT5600, Руководство пользователя

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C H A P T E R 7 – T E S T S A N D T E S T C O N D I T I O N S
AT5600 User Manual 98-119 issue 14
Page 142
Notes and Hints on use of the SURG test
Even though the energizing pulses are applied to one winding, it is important to
note that this voltage will then be induced on to all windings on the transformer
under test, in the same Volt/turn ratio.
To prevent damage to the UUT, or to the AT5600, the SURG test should always
be applied to the winding with the greatest number of turns. You should also
check that the design of the other windings that will be energized can withstand
the induced voltage.
It is also important to note that the Volt Second numerical result of the test is
characteristic of the whole transformer, not just the energized winding. The Surge
test tests all windings on the transformer.
Please also note that the maximum Surge signal is dependent on the inductance
of the part under test, if the LS inductance is below 125 uH.
Please see 10.2.17 for definition of this.
Effect of programmed limits
Unlike all the other tests on the AT5600, the limits you set for PASS/FAIL criteria
can sometimes affect the measured result, if the limits are very wide, and far from
the nominal.
This is because the AT5600 has variable sample rates that are used on surge.
These are 25,50 100 200 400 750 kHz and 1, 3 6, 12 MHz
Very small mVs SURGE results use the fastest sampling rate, which give better
resolution and repeatability.
Larger results (i.e. oscillation over a longer period) will use a slower rate to make
sure that all the characteristic decay waveform is captured.
This sample rate is selected automatically by the AT5600, based on the Max
limits you have entered, the unit then knows that it is expecting a result of this
order of this magnitude.
However, if your chosen limits are much larger than your expected result (e.g.
using a 100 mVs limit on a part where you expect 10 mVs) then this can in
extreme cases result in a non-optimal sample rate being used, and in turn a less
accurate result.