Standard voltage transformers

Standard voltage transformers are extremely accurate and are equipped with numerous coil ratios to meet the special requirements of the Physikalisch-Technische Bundesanstalt in Braunschweig (PTB).
They are used for the following purposes:

• To measure ratio errors in voltage transformers during series and prototype testing on test rigs and in laboratories for manufacturers, users and universities.
• As a standard with which to measure and compare ratio errors on voltage transformers for official measurement and calibration.
• To measure the no-load operation and short-circuit losses of transformers.

Precision voltage transformers are normally calibrated to a fixed resistance (usually to the input resistance of the measuring bridge), so that together with the high quality active section an extremely high accuracy can be achieved, allowing in many cases the ratio error of the precision transformer to be regarded as negligible during measurements.

If required, these transformers can be approved by a calibration authority chosen by the customer.

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