Hay guys I need yours help. I want built a step dawon 12-0-12, 10 amps transformer. But problem is I don't know the formula. So any buddy can be help me

 

The whole transformer from scratch or modify one?
Max.

 

Hello,

You just hyjacked someone others thread:
Step Down Transformer Grounding Question (kmpres)

Now you have a thread of your own.

Have a look here for information on transformers:
http://educypedia.karadimov.info/electronics/electricitytransformers.htm

Bertus

 

The whole transformer from scratch or modify one?
Max.

Sir.
I can't get yet any solution pls help me

 

The simplest way would be to get an already made off the shelf unit from an old 12 volt automotive battery charger.

The vast majority of them are designed around a simple 12 - 0 - 12 secondary winding.

 

For modifying your best bet is a Toroidal of the required Va, they are very simple to wind a secondary on if you have one with one with a primary suitable for your local power.
You can find the Turns/v from a secondary already present.
Max.

 

This job is a gigantic PIB. You have to start with the qualities of the core material, figure how many pounds of core you need for the watts, the number of turns in the primary for your local voltage, allowing for the power line to be +/- 5%, then the secondary turns allowing for efficiency losses in the core, and wire gauge. It takes a lot more than one formula to do all this. Do you even know where to buy the core? I don't.

Either get a transformer made for this job or at least get a core that has the right primary on it.