Selecting appropriate copper gauge for transformer

Hello, please I would like to know how to select the appropriate copper gauge for the primary and secondary winding of a 1000W, 220VAC/24VDC center tap inverter transformer and how to also select for higher power inverter transformer. I have read through a couple of stuff I found online but I still need clarity on this issue. thanks

Hi,

At first sight this is a problem of dissipated power.
For DC currents this is I x I x R_Cu.

But it isn't that simple.
It additionally depends on:
* core dimensions
* isolation material
* frequency (skin effect)
* ambient temperature
* coil stacking
* RMS current
* additional heat sources (like core loss...)
* local safety regulations (of your country)
* ...

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Maybe you want to go the safe way...then use the next larger diameter.
But mind, that you need more coil space for the thicker wire...and maybe the result is not that good as you assume, because the skin effect reduces effective/conductive wire area.

Klaus

I found a core having the following parameters:
window area = 0.00128sq. m
winding area = 0.00075sq. m
turn length = 0.144m

Using the info from this site(https://ludens.cl/Electron/Magnet.html), Allowing for 5% loss in the 220V winding, I got a current of 1.57A and a Max Power of 346VA.

My question is this: Do I compare the 1.57A to AWG to get the right guage to use?

Do I compare the 1.57A to AWG

Click to expand...

Heat generation is a chief factor you should consider.

Links to charts of wire gauges showing safe amp-carrying capacity:

http://amasci.com/tesla/wire1.html



http://www.powerstream.com/Wire_Size.htm

Here's a link to another wire gauge table. Its ampacity values are much different than the other tables.

**broken link removed**

Possible reason for the disparity: One source may base ampacity on a higher temperature which makes the wire get too hot to hold, while the other source may use a lower temperature where copper's electrical characteristics start to change even though it is only warm.

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You want a certain output. I had to puzzle over a similar question. The best approach I found, is to ask:

(b) If I decrease wire thickness, how much does my power output decrease?
(a) What additional expense is needed somewhere to raise it back to my desired power?

By repeating these calculations you should find a breakeven point.

I got a current of 1.57A and a Max Power of 346VA.

Click to expand...

Sounds like the transformer core is too small. Are you talking about a 50/60 Hz transformer? How did you choose core size and turns per volt?

FvM said:

Sounds like the transformer core is too small. Are you talking about a 50/60 Hz transformer? How did you choose core size and turns per volt?

Click to expand...

It is a 50/60Hz transformer extracted from a damaged UPS. The core size was gotten by measuring the window area of the core and the turns per volt was calculated using this formula:

t = 1/(4.44 x frequency x area in sq. m x flux density)