Digital ratiometer PWR3A

for transformers

The great advantage of the PWR3A compared to many of the other instruments on the market is its simple set-up. In most cases the required parameters must be looked up in tables on the basis of the vector group and the code number of the transformer to be measured, and set up at the instru-ment by means of rotary switches or keys. This often results in a wrong set-up or uncertainty regarding the set-up since some of the tables are confusing. Such a manual set-up is not necessary with the PWR3A transformation ratio measuring instrument. You simply type in the vector group with the keys. The only thing you have to do is to connect the transformer being off-line to the device and release the measurement; all three phases are measured consecutively, all connecting and short circuited procedures at the primary and secondary volt-age sides are performed automatically before each measure-ment. Of course it is also possible to measure just one phase, e g. H2. An adjustable set value permits the display of an error or deviation of the measured transformation ratio. Further, an automatic control of the tap changer is provided. In this case all phases and taps are measured consecutively, and all the results are stored inside the instrument (using the trans-former specific memory), printed (if a printer is connected), and transferred to the PC (if connected). Using the internal memory all results for all taps are written to a transformer specific area. Furthermore, the transformer specific set point values, the vector group and additional information describing the trans-former (e.g. serial number, location …) are read from the memory when selected and displayed on the LCD.