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 157
Specifying the Test Limits
The AT5600 offers you three ways to specify the test limits:
•
Using a normal AC (RMS) measurement.
•
Using a rectified (mean) measurement.
•
Using a DC (mean) measurement.
Generally, the AC (RMS) value would be used, but you could use the rectified
(mean) or DC (mean) measurements if, for example, you are testing transformers
fitted with a rectifying diode.
WARNING: While the AT5600 can test, transformers fitted with a rectifying
diode, a capacitor must not be fitted as part of the rectifying circuit. Any
charge remaining in the capacitor could damage the AT5600's relay matrix at
the end of the test.
To give the best accuracy, the DC measurement is averaged over the period of
the energizing frequency. In addition, the VOCX test can be used to test the
polarity (or phasing) of the windings, if this is required. This is not available when
some types of external source.
Trimming of requested Voltage (when using Step-up transformer
with AC Interface)
When using the AC interface with a step-up transformer, the AT5600 uses the
Class D drive (used on VOC MAGI WATT and STRW) and routes it thought
the AC interface. The AT5600 calculates a nominal value for the voltage
needed to get the target value based on your requested voltage, and the
programmed ratio of your chose transformer. The AT5600 will then attempt to
trim to get the exact value that is needed.
If either of the following two conditions are exceeded, the AT will report a
trimming failure (0020):
If the trimming requires deviation of more than 60% from the nominal
(i.e. 100V nominal, but trimming requires excess of 160 V or less than
40 V)
If the trimming requires outputting more than 230 V
Please also see
14.6.34 for specific advice on programming the test, and
10.2.9 for test accuracy specification