Query on Transformer markings

[kev2632]

Hi

I think I've got what all the transformer markings mean, however I ain't 100% sure what the steps +- means ?

Is anyone able to explain to make sure what they all are ?

Thanks

 

[waross]

0.42kV
Taps:
0.42kV +2.5%
0.42kV + 2.5% + 2.5% (+ 5%)
0.42kV - 2.5%
0.42kV - 2.5% - 2.5% (- 5%)

 

[kev2632]

0.42kV
Taps:
0.42kV +2.5%
0.42kV + 2.5% + 2.5% (+ 5%)
0.42kV - 2.5%
0.42kV - 2.5% - 2.5% (- 5%)

So what does this mean exactly sorry for the tap % and step % in basic terms ??

Thanks for the reply much appreciated

 

[dpc]

There are primary taps (assume off-load) that allow a voltage adjustment of plus or minus 5% from nominal (or from 95% to 105% of rated voltage), in 2.5% steps. So you will have the nominal center tap, then two taps above and two taps below the nominal voltage. So steps of 2.5%. This is totally standard. The best source of information is always the transformer nameplate. Maybe someone could take a picture for you. I wouldn't put too much faith in what is in this computer model, unless you are really sure of the source of the information.