Multiple primaries question

[Rodeodave]

I have got a Sedlbauer 1500VA toroid with one secondary @ 48V and multiple primaries form 0-220-230-240 Volts.

The mains in austria are 230V50Hz

My question is:
If I wire it 0-220V I will get a slightly higher secondary-voltage (desired), right? But what about the VA-rating then?
Is this a good idea at all?


Btw, anyone knows where to get nichicon "gold tunes"?

[Bazukaz]

If you supply higher voltage than designed , trafo's core will go closer to saturation , and iddle current may increase somewhat.A small voltage increase should cause no problems , but you would get only a slight difference in secondary voltage (approx 4-5% or so).

[AndrewT]

Hi,
try it at 220Vac tapping but monitor it often for overtemp.
Make sure the case is well ventilated.
If there is a lot of other heat production in the cas ethen stick with the correct voltage tapping.

If you need extra voltage then simply add some secondary turns under the outer insulation.

[davidsrsb]

How stable is the voltage where you are?
The transformer might be OK when you test it and burn later when the voltage rises. Transformer manufacturers are not naturally generous with the iron.

[Nigel Goodwin]

Back when the UK was 240V and the rest of Europe 220V, we used to see a LOT of transformer failures on 220V equipment used in the UK.

However, doing that over runs EVERYTHING, not just the transformer, so it's far worse. In your case, designing the circuit, over running the transformer voltage slightly shouldn't really be a problem, as long as run it at less than it's original VA rating.

Have you tried measuring your mains voltage since the change to 230V?, it's quite possible it was only a theoretic change? - as in the UK, where it's still 240V, but that's within the tolerance allowed in the European wide 230V specification.