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Transformer question--need transformer that puts out nominal 240V for European Amplifier

Maybe some European members who have moved to the US know the answer to this.

I bought a European Amp to use in the US. Many Euro amps work on US 240 but this one has a phase protection circuit and it won’t work on US 240. (the difference is that US 240 is 2 legs of 120v out of phase so that they are 240V relative to each other. The Euro system is one hot let of 240V and a neutral leg of 0 V or ground).

So I bought a cheap but sizable (3000W) step up transformer off amazon to test it with before I shop for a quality transformer and very surprisingly it creates US system 240 (2 legs of 120V). You might think this is not surprising except it is marketed to run EU equipment and even has EU style plugs. I don’t even know how they do the phase shift. A simple 2x voltage transformer (often called autotransformer) would create 240 EU standard.

So my question is does anyone know how to select a transformer that takes 120V US and converts it to 240V EU standard?

Thanks,

Jerry

128x128carlsbad
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holmz's avatar
holmz
2,328 posts
 

@carlsbad I explained previously that if there is a center tap, then the transformer’s opposing legs will be +/- 120.

One of the internal wires should be hooked to ground

However if the amp is a typical piece of Eu gear then it is likely double insulated and it does not matter if it is more like a push-pull or single ended voltage. Not sure about amps, but power tools are that way.

 

Plugged the power cord into the wall outlet and checked the 240V output.

Hot contact on 240V receptacle to equipment ground, 120V.

Neutral contact on 240V receptacle to equipment ground 120V

you only changed the polarity 180 degrees by flipping the +/- sides…

jea48
4,450 posts
 

Plugged the power cord into the wall outlet and checked the 240V output.

Hot contact on 240V receptacle to equipment ground, 120V.

Neutral contact on 240V receptacle to equipment ground 120V

you only changed the polarity 180 degrees by flipping the +/- sides…

No, I reversed the hot and neutral conductor polarity.

holmz's avatar
holmz
2,328 posts
 

No, I reversed the hot and neutral conductor polarity.

Yep- and that would be like flipping the phase polarity on the 240v (which is +/- 120v)

jea48
4,450 posts
 

No, I reversed the hot and neutral conductor polarity.

Yep- and that would be like flipping the phase polarity on the 240v (which is +/- 120v)

Not really.

Reversed receptacle polarity is where the HOT branch circuit conductor is connected to the neutral conductor terminal/contact on the receptacle.

The neutral, (The Grounded Conductor), is connected to the Hot terminal/contact on the receptacle.

Can be dangerous and possibly an electrical shock hazard. Example changing a burned out light bulb when the circuit feeding the socket is energized. The outer shell of the socket would be HOT...

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