# Power transformer with four similar secondary windings connected in parallel

I need help with the math that is glossed over in nearly every explanation I can find on the web.

I have a transformer with a toroid core and primary that were professionally assembled and rated at 2150 VA. I have wound four separate secondaries. I am getting 0.8 V per turn on the secondary and 16 turns yield ~14.4 V with a geometry that requires about 18 feet of 2 AWG solid copper magnet wire rated at 0.1563 Ω/1000 ft. That gives me ~2.8134 mΩ in the copper. Each secondary, in isolation, does show about a 0.4 V drop at 145 A so I'm comfortable with that number.

What I would like to see is the math that computes the current in each winding and the voltage drop across each effective series resistances before I hook these windings up in parallel and try to draw 480 A from it.

I've done the math before with two sources, but never a third or fourth, and it seems no one else has either. I've tried brute force Kirchoff's law in this funky hyper bridge circuit system of equations but I cannot get answers where Vw1 = Vw2 = Vw3 = Vw4. Clearly I am not as good with algebra as I thought I was.

simulate this circuit – Schematic created using CircuitLab

Can some one show me the math? I want to plug in fractionally dissimilar values to see where competing current flows in my secondaries become a concern.

Edit: I know this much secondary current will push this core into saturation. Right now I just need to know if I can manage the expected variance of these multiple secondaries, I will invest in a higher-rated core later. I didn't mean to frighten anybody.

• A thevenin equivalent would be great too, if possible. Commented Feb 17, 2023 at 22:43
• Simulation seems ideal for this. Commented Feb 17, 2023 at 22:52
• (um - 2150 VA < 14.4 V * 480 A.) (Just what are you going to power?) Commented Feb 17, 2023 at 23:12
• @greybeard I think he is saying AC Voltage (VAC), not VA (volt-amperes) Commented Feb 17, 2023 at 23:23
• (@RogerDodger Could have been VA capacitive, but probably you are right. Still - 2150 V? Another mystery.) Commented Feb 17, 2023 at 23:27

• (bridge rectifiers that's why I asked about what's to be powered - AC, DC, stabilised, intermittent or constant…) Commented Feb 18, 2023 at 12:20