Similar 115v to 24v Transformer

[speedypro]

Got this device to change a step down transformer. But Im not sure if this transformer that the customer bought is ideal.

Image not edited:



This is what I need to replace with the above pic:







Based on the above, is there a similar 115v to 24v (12v on both pins)

[stj]

Re: Similar 115v to 24v Transformer

it will do 120 or 240 input and 24v output.
but you need to work out the original transformer wiring.

[speedypro]

Re: Similar 115v to 24v Transformer

it will do 120 or 240 input and 24v output.
but you need to work out the original transformer wiring.

Well... Ive desoldered the old and found this model:



The 15v and 25v are in use. I cant even find that exact transformer.

[eccerr0r]

Re: Similar 115v to 24v Transformer

Actually it looks like it's using the 25 and 12.5 pins, right?
Then that other transformer probably will work just fine. Make sure you wire the primary correct, need to make sure the two primaries are in series in the right way.

Are the two transformers similar in size at least? The "replacement" transformer looks very small. Also need to connect the secondaries in series as well.

[speedypro]

Re: Similar 115v to 24v Transformer

Actually it looks like it's using the 25 and 12.5 pins, right?
Then that other transformer probably will work just fine. Make sure you wire the primary correct, need to make sure the two primaries are in series in the right way.

Are the two transformers similar in size at least? The "replacement" transformer looks very small. Also need to connect the secondaries in series as well.

Size not an issue. I ran into one: Ive solve the input of 115v but I cant get 12v and 24v output. Well... I get the 24v but how to get the 12v? As in image, that way makes both pins 24v. I may need a diode to prevent the current from returning. Which diode is best in this case? A 24v rectifier diode? Or any voltage above 24v?

[stj]

Re: Similar 115v to 24v Transformer

the red loop should be one tab left, not on the yellow.

[speedypro]

Re: Similar 115v to 24v Transformer

Not really. Joining those two reds I get 24v. So I added a diode which solves it:

[stj]

Re: Similar 115v to 24v Transformer

no, that's wrong and not 24v anyway because the yellow wire is on a winding with one end not connected.

you want: black to the first 0v, red to the first 12v, and link it to the second 0v then yellow to the second 12v.
the link puts them in series so the second winding actually reaches 24v (12+12)

[budm]

Re: Similar 115v to 24v Transformer

What is the added diode for, that is not right at all.
The cold side looks to be using 25VAC winding with center tap.

[speedypro]

Re: Similar 115v to 24v Transformer

Shyt! Ok Ill wait for the customer to tell me nothing works.

[budm]

Re: Similar 115v to 24v Transformer

BTW, replacement transformer windings, the way you have it wired up you are only using one of the two 12V winding, the other 12v winding (B) is not being used at all.

[speedypro]

Re: Similar 115v to 24v Transformer

The drawings on the images made it clear. Im not way into transformers but will make the changes when customer returns. Thanks.

[budm]

Re: Similar 115v to 24v Transformer

I still do not understand where that diode comes from?