Transformer winding specs for 220/12 V

You cannot make a transformer yourself for less than the mass produced prices they are selling for currently.

If you want it dirt cheap go with an e-bay item and modify it if it is not exactly what you want like this one.

Failing that just ask for 3 different quotes from local mfg's and you will find it will not break the bank.

ahk123,

That means you want 100A. Mein Gott! You'll need something like a manual lathe to wind it. Do you have that? Couldn't you run this thing at a higher voltage, maybe 48V where you'd only need 25A? That would be a lot easier to wind.

Do you have any coil winding experience? I can tell you the specs, but I can't teach winding over the internet. Do you have access to laminations or cores? Which kind? If it was me, I'd buy one that had the right primary and VA rating and rewind the secondary if I had to.

I think he got that part wrong. If it is 1.2Kva on the primary it would be more acceptable at 5A or thereabouts.

What about 1.2va, that would be 100mA.

I cannot think of anything you would readily need 100A for at 12Volt, do you?

Case491 - I did not get kVA and VA mixed up- my fault I shouls have made it clear that I need the specs to make a 1.2kVA UPS i.e 12v battery - inverter - transformer - 220V ac

That sounds better.

How long do you intend to run of this inverter UPS? It still sounds a lot and if you have a chunky battery doing 24V / 50A for any length of time, you might as well go 48V and half the Amps again but the temperature range will drop even lower. With this the safety factor will increase so you will have less difficulty with safeguarding it and no cooling needed. I used a 12V 100Ah marine deep cycling battery for years to run my motor home. I will tell you that even at 25% of it's load, that is running it continuously for 4 hours at max until empty, the thing got quite hot. If I ran it at 10% of it's load for 10 hours you would not feel a thing.

TVP45

Thanks for you response - In fact the transformer will be a part of UPS using an inverter - I will relook at the design to increase the 12V battery to 24V to reduce the current to 50A. I have access to an electrical workshop whould would do the winding for me and provide whatever laminations and core required. I would appreciate the specs pl

Find some old computers and take the power pack out of them. They usually have a switch on them that has a 120V or 220V setting. You should be able to parallal two or three to give you the kVA, cause I think your looking for 12 DC out. Right???

OK. What battery will you be using?

I will be using a 120Ah battery, the nominal load would not exceed 400 watts.

Now you're confusing me. That's not hard to do, but I'm trying to see if I can help. You said you wanted a 1200 VA transformer, but your nominal load is 400W? Is the peak load close to 1200 W?

Even 400W is more than 30 Amps at 12 V. That seems like a hard load on a 120 Ah battery.

But, tell me what kind of battery you have. And describe how you plan to do this in a little more detail. Do you have a desired charging voltage, possibly with a curve?

TVP45 - Nominal load would be 400W, allowing for 200W as spare capacity - 1000W I choose so that it can take starting current of two single phase fans (80 watts @ 220V AC).

DO you suggest a larger battery, it is a lead acid battery, unfortunately I do not have curves but charging voltage is 14.3 Volts. Thanks

Ahk123,

Missed your post till now. So, if you want 14.3 VDC for charging, let's assume you'll use a full wave bridge, so two diode drops = 2 x 0.6 VDC = 1.2 VDC.

Add 14.3 VDC + 1.2 VDC = 15.5 VDC. Now if you use no filter capacitor, then you'll want a secondary Voltage of 15.5/0.9 = 17.2 V_rms. That seems just a little bit high, but I'll take your word for it. So, we need to know something about your core - the type of material and the size - and we need the frequency of your power. I'm guessing 50Hz. Is that right?

TVP45

Thanks

The freq is 50Hz, I lack info on the core and size, the workshop friends who have agreed to make the transformer for me say that they can get the necessary core and sizes if they are specified.

please tell me ups220/12v transrormer wire winding turn and desigm and winding table.