[slasher102]

I have a toroidal step up step down transformer it only has three wires and a diagram on the side that doesn't mean a lot to me

this was out of a step-up step-down transformer Pictured below that was working fine 250v in 115v out
the problem was the American plugs where not solid enough so i my infinite wisdom a pulled it apart as i do with most things.
but now i cant figure out how to connect it to 220v and get 115v out.

next time i will leave it alone.

3000 Watt 110v Transformers, 220V - 110V Voltage Transformer, Step Up and Step Down, UK to US US to UK Trans formator 3000W


main problem in a nutshell is it only has 2 red wires and 1 black ???

[CitizenOfDreams]

The input voltage goes between "0" and "220V".
The output is between "0" and "110V".

[slasher102]

Its ok cheers i have sorted it, its because its a Autotransformer Ha

[slasher102]

you are spot-on cheers i was having a blond moment.

[CitizenOfDreams]

Happens to the best of us. :wave:

[Al_The_Man]

If you have it connected across NA 240 and use one end to the 120v CT point measure from here to GND to see how much it is above 'zero' .

[CitizenOfDreams]

If you have it connected across NA 240 and use one end to the 120v CT point measure from here to GND to see how much it is above 'zero' .

There should be about zero relative to the ground on the "RED 110" wire. 120V above ground on the BLACK wire.

[Al_The_Man]

There should be about zero relative to the ground on the "RED 110" wire. 120V above ground on the BLACK wire.

Correct.
The reason I mentioned it is that if feeding any 120v devices or outlets, this should be considered the neutral conductor or terminal.