110v to 220v AC stepup converter

[duwgomufo]

I'm looking for a schematic for something like this: **broken link removed**

I only need the step UP part (110v to 220v AC), and it has to be at lest 300w.

Any help will be apreciated. Thanks...

 

[hameeds01]

it has just a stepup Transformer (300w)
can u built a Transformer urself ??

 

[duwgomufo]

Yes i probably can. What do i need exactly, alot of wire and a ferromagnetic core? if i remember my college class well... :wink:

I have this:

**broken link removed**
**broken link removed**

I have 3 roll of that, it's double insulated wire, i think its gauge 28. Would this be suitable?

And for the core, is there any special shape i should look for or anything ferromagnetic will work?

Finally, what would be the spec, like number of turn on primary/secondary (i guess it has to be 1:2) on this point i'm really not sure, it has to support 300w so how can i know how big it has to be? I also have alot of old pc and xbox power supply, is there any part i can use there?

 

[dick_freebird]

I would be hitting the electronics surplus places looking
for a suitable transformer, good to go. Dirty iron sells way
cheaper than new wire, let alone labor and small details
like how much core for how many amps and so on that
might tend to make your first try, not be the last.

"Isolation transformers" are often found with center taps
that will let you step up or down 2:1 (depending on if you
have Euro equipment in the US or vice versa, either way has
its uses).

At only 300W, you might find what you want in a "travel
adaptor kit", possibly even cheap. You'd want one that is
for using European appliances in the US.

 

[duwgomufo]

Maybe i'll don't even have to leave my house
I just went trough my "personal electronic dump" and found that: **broken link removed**

I think it's from an old audio amplifier. Is this the kind of transformer i need?

I guess the top black and red wire are for 120v AC input and and the 3 bottom are probably some kind of center tap or voltage divisor, but i have no clue on how to test it to find what is the turn number ratio between primary and secondary coil. Anyone know how can i do that?

And is there a sure way to know if it can support 300 watt?

Edit: I forgot to mention, what i'm trying to do is to take a 120v input and get a 220v-240v output so i can power a 300w EU aquarium heater.

 

[duwgomufo]

I would need help on this one. I'm about to try something, but i just want to be sure i'm not trying something stupid with high voltage.

So i'll put the black and red top wire directly on 120v AC (wall plug) and put a 1MΩ between each wire from the secondary coil (bottom wires, red green and yellow) and then take a read on voltage across the resistor (if my math are exact, it should let a maximum of 24µA if the voltage is 240V, which is what i'm trying to get at the end, and i guess this amp. is a safe working zone ). I'll then divide 120v by whatever voltage i get from the 3 sec. coil and it should give me the turn number ratio. So question #1, is that all make sens?

Let's say i find a sec coil with a 1:2 ration, could i plug the 120v directly to that coil and then collect 240v on the secondary, directly plug to my heater, without any additional hardware? That's question #2.

And question #3: What will happen if i plug 120v to the red/black primary coil wire with no resistor on any other coil? Can i assume the primary coil inductance will block the 120v AC or is there a risk of frying the coil with too much current?

Any help/confirmation with one of those 3 question will be appreciated. Thanks...

 

[snafflekid]

Nobody rolls a good transformer on the first try. It is a skill that requires a lot of spare parts to play with, debugging and a few failures along the way. Having said that, you could become a very handy application engineer in magnetics.