Transformer Design 24V - 220V

1500W approx 60 amp in py wndg in py.Tfr construction is for cmpnies with vast years of R n D not for all people.better you search in market to get your specification.

GA hithuanand. _{(But the spelling needs a little improvement. )}

Transformer design is more complicated than many people think. A simple review of three dimensional vector calculus to attempt Maxwell's equations in a start of transformer design should show people that this is not as simple as some might think. Many smaller scale transformer designs can be tinkered by an individual but 1500W is beyond the scope of tinkering.

A poorly designed transformer can easily loose 20% of the power applied due to wire resistances and eddy currents in the core. For 10W of transformed (output) power then at least 12.5W must be applied on the primary side, this leads to a manageable 2.5W being dissipated.

10W=(100%-20%)*Input → 10W/.8=Input=12.5W

Scaling this to 1500W output will mean nearly 400W must be dissipated by the transformer. This much of a power loss can overheat insulation. So this is well beyond the region of safe tinkering.

Ok sir that make more sense.

sweet jesus....

24V to 240v at 1500W...not for the faint hearted back yard inventor

Toroids is where I would start for such a project. Calculators are in abundance on the WWW to answer questions about wire specs..

...and don't forget to include a temperature sensor in your windings if you must make one!!!

Hi,

Looks like no one tried this combination here. I have seen a invertor with 1500W running on 24V battery and it costs 18000 Indian Rupees.

Does that mean that we cannot build one with the above specs? Or is there any other limitation that you are pointing out?

Regards,

Bency

Well the first limitation is that you've yet to show any understanding of electromagnetism fundamentals or any grasp of our concerns for you trying to do this build. So even if you were handed a schematic and assembly drawing, I'm not sure you will be capable of building an inverter safely. I find it even more doubtful you could troubleshoot a sound design that was miss-assembled.

A case in point, you originally asked for a transformer to convert 24V to 220V. This implies that the input and output voltages are AC signals. Now you're talking about somebody's 24V battery to 220VAC inverter system. I don't wish to be cruel but I'm not sure if you know the difference between DC and AC electric power. So how can I hope to discuss with you the idea of magnetic field strength, magnetic flux density, hysteresis, eddy current loops and quenching the core.

Dear RedFred,

Thanks for your discouragment here. You think you are the only one here with all the knowledge? and no one else can build a transformer? Looks like you cannot help and you would like to just give limitations and discouragement to people who are willing to try.

For your kind information, I have constructed a 400W invertor on my own including the winding of the transfer and it works like a charm. Please do not underestimate people who ask questions here. Share your knowledge if you have or else keep quite.

Regards,

Bency

Mate, perhaps in future it would be wise to clarify all aspects of your position in your opening post.

"Can anyone let me know the core size and the copper wire gauge and number of turns needed." ...such a question is reserved for no0bs and it is my opinion you were treated as such and warned of the problems associated with a transformer build that would meet your desired specs..

So, my question here is do you first analyze the person first before giving a solution which I asked?

All, I want is just the calculation. If no one knows then let me that rather than telling limitations and understanding the knowlege level.

Regards,

Bency

http://sound.westhost.com/xfmr2.htm

http://www.smps.us/magnetics.html

http://www.bcae1.com/trnsfrmr.htm

...your question in your opening post cannot be answered with accuracy based on the information you provide, which is limited to:

"Input 24V, Output 240V, Watts: 1500W continues [?], Frequency 50Hz"

Please read the above three links and come back with more information so that I and others may help. Cheers

bencyp,

No, I do not think that I am the only one here with transformer knowledge. There are many people here that have much more practical and theoretical knowledge than I do in many fields, particularly transformer design. Because of this I stride to not underestimate any person's knowledge. Instead I have learned that analyzing a person's present knowledge gives a starting point that permits me and others to add to the person's knowledge instead of just baffling them.

I did taunt you for a response to show some of your knowledge earlier by asking you to review Maxwell's Equations. You will notice that these equations change in the presence of a magnetic material. Now even though these equations are the actual heart and soul of how a transformer functions and that all transformer design equations linear and non-linear can be derived from these equations, I would expect this to be a baffling answer. (I didn't fully grasp the significance of these equations until I took a post graduate class on switching supply design that did derive everything magnetic related from these equations, but that's another story.)

Now CraziestOzzy and others have provided you a few web links that explain some of the confusing aspects of transformer design. I hope that you read these pages and get a better appreciation for the complexity of transformers and realize that as CraziestOzzy pointed out, the information you have given us is inadequate to say that this or that equation is the one you need to follow.

You've now informed us that you've already fabricated and successfully operate a 400W inverter. I now believe that you can troubleshoot a 1500W system without killing yourself, others or just starting a fire. So I presume that the circuit you are using utilizes an "H" bridge design approach. It's the easiest way to get a unidirectional voltage source (battery) to drive a load bidirectionally. Make sure that all of the fly-back diodes are operating as anticipated. I mention this because if one does not permit the core material to "relax" by releasing the unused stored energy then to reverse the field will take a considerable amount of wasted energy before permitting a reverse cycle to couple from primary to secondary.

This brings up my first concern, I wonder how efficiently your 400W system works? As I mentioned earlier, the power losses of a smaller system can often be overlooked. But if the earlier system is the basis for the nearly four times larger system, then acceptable losses can quickly turn into prohibitive losses since many of the reasons for a power loss are the non-linear aspects of various components.

I recognize that I've yet to discuss at all your transformer parameters. I wanted to first make sure you have a good understanding of the working system parameters to attempt a discussion of the transformer. Well I suspect that the root of your problem will be the flux density in the core path for the transformer that you are using. At some point in each half wavelength of your 50 hZ signal the energy you wish to briefly store in the core is saturating this part of the core and thus you now have a completely different magnetic circuit topology and input to output relationships of your transformer breaks down. Now remember that most of the magnetic energy will be stored in the transformer's gap and not the core material. No amount of winding parameter changes (turns, copper area, etc.) will fix this design failure. The only options in this are to store more energy in the gap by adjusting gap width(therefore less in the overloaded core leg) or to increase the area of the leg and therefore again decrease the flux density. Adjusting the gap width has the complication of changing the transformer's impedance matching capabilities and is why in the broad bandwidth audio link gapped transformers are frowned upon.

I hope that this has helped, but I seriously doubt it. As this entire thread has hopefully shown, transformers are very complicated passive components. But when you return and explain what you don't grasp, I and others will help you to understand what is going on.

redfred

My primary concern is what type of core (with its many connotations) is going to be used, before I answer any question related to the OP's concerns.

$399 is ~ Rs18326.71 (rupees)

With a few minutes of web searching, I'm seeing several 24Vdc to 220Vac 50Hz 1500W (2800W peak) inverters, modified square-wave output, for about $200. A true sine wave output inverter with the same specs runs about 2x the cost or $399.

Once you have a proven design (no small effort there), you can shop around for all the parts to build one yourself. I believe you can acquire all the hardware for about 1/3 to 1/2 the prices listed about, assuming bulk volume part pricing.

There will be some significant effort learning and writing the program code for the controlling microprocessor. After many hours of assembly and testing, you "might" have a working inverter that looks like crap compared to the nice aluminum finned chassis of the store-bought unit.

When you add in all the time you spent building and testing the unit, the net cost will probably be higher than the direct purchase cost listed above.

Do you still want to attempt to build this yourself?

You could try using several transformers and hook them up together to get what you want. Perhaps use microwave oven transformers of same build/type and rewire and/or remove wire accordingly to get what you want. That's assuming that losses are not an important factor in your idea.

There is heaps of info on the WWW about these conversions.

...and I am ignoring your lack of reference to AC/DC in my assumptions that offer you help. I assume input is AC.

It is not difficult to size a core on paper I can readily give you the formulas, the real problem is that how and from where you will get only one core manufactured? For the same KVA rating you can get numerous alteration in physical traits for example overall dimensions, window areas, width of core etc.

I have seen some hobbiests completing project by acquiring a dammaged transformer and rewinding it to meet their specification criteria. If that is the case with you following will help you:

Primary or secondary turns = vots/voltage per turn (take voltage per turn about 1.5 volts per turn)

Conductor area = primary or secondary current / current density (using copper conductor take current density 1.44 A/mm square)

For suitablity of the core to match your requirements as a rule of thumb consider that the net copper area in the window is 0.6 times the crossection of iron in the core.