Dual primaries to 230V: the dot

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Up to now, I always had single primary power transformer, thus I am a little discomorted.

Here’s this little xformer, dual primaries, where the dots are on the outer pins.

To make it a 230V transformer, I bridge the outer Pin (dot) with the inner pin (no dot) of the other primary, correct?

Is there a method to measure/test it without connecting it?

Thank you all!
 

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Easy, use a low wattage bulb (DBT) in the primary as you test it. If you get it wrong the bulb will light and the secondaries will have no voltage.

The pin configuration looks a bit unusual as you would expect the inner pins to join, however the dots clearly show not to do it that way.

So use a bulb and be sure.
 
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He's asking without connecting anything, so how's a bulb helping with that?

I would recommend a multimeter or a oscilloscope (scope on the secondary only please).

Unfortunately there is no way of figuring this out without connecting anything.

That being said, if you just keep consistent with connecting the dots the way you want it, it should be fine.

If the DC resistance isn't to low, you probably can also hook it up to an audio amplifier and use a sine wave.
Or when the resistance is rather low, use a resistor in series with it so you won't damage the amplifier.
Downside is that voltage drops.
 

stv

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I suppose myleftear was intending "without connecting it to mains"?

You could connect the primary windings in different configutations to an amp playing a low voltage 50 Hz sine wave. Measure the secondary outputs to know the correct connection.

Edit: or measure primary impedance of connected coils. Higher impedance is the correct connection.

Edit2: just saw b_force was quicker ...
 
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Up to now, I always had single primary power transformer, thus I am a little discomorted.

Here’s this little xformer, dual primaries, where the dots are on the outer pins.

To make it a 230V transformer, I bridge the outer Pin (dot) with the inner pin (no dot) of the other primary, correct?

Is there a method to measure/test it without connecting it?

Thank you all!
Well the CE mark is definitely fake, so perhaps don't use it and live a long life...
 
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The pin configuration looks a bit unusual as you would expect the inner pins to join, however the dots clearly show not to do it that way.
How can you see the pins? ;)

@myleftear - Start with the datasheet... Attached. Key information pasted below for your reference.

1713382067303.png


Even with the wonky CE mark... if you got it from a reputable source... I wouldn't give it a second thought.
 

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Sorry - quickly deleted a post b/c I had a brain fade while looking at an Antek transformer and a Talema. LOL! Apologies. So, for those that get e-mail notifications with a snippet, ignore. :)

^ As Mooly surmised, you would not connect the middle pins (2 and 4). You'd likely connect 2 and 3 (or 4 and 1). The datasheet matches the diagram on the transformer, which is good. I was curious.
 
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