Hello, i have a transformer that turns 120 volts AC into 25 volts ac, the output is 1 to 2 amps, it can produce 3 but it gets really hot. I need more amps at 25 volts.

Can someone please help me understand if i can get 25 volts at more amps from the wall outlet socket?

can this be done? i would love to be able to run 3 or 4 amps without the transformer getting HOT.

 

hi,
Transformers are manufactured to a specified VA [volt-ampere] rating.
Nominally the TX you have is 25V * 2 = 50VA.
If you increase the current drawn from the TX secondary you will exceed the design specification,
it will get hot and the 25V will fall to a lower value.

The 240V wall outlet socket in the UK can be fused upto 13A, as you dont say where you are posting from I cannot comment on your local mains supply, but I would expect to be over the 50VA you are requiring.

Simply... you need a TX with a higher VA rating, say 25V * 4 =100VA.

Eric

 

i am looking to reduce 60 hz 120 volts down to 25v, but whats the max amps i can get when reducing? where can i find or how do i make this transformer???

THanks.

 

hi,
The Imax for the secondary winding of the transformer depends upon the VA rating of the transformer. As conventional transformers can be wound to give a rating of 100's of VA, the limiting factor for a domestic transformer would be the rating of the local supply domestic outlet.

As I said, UK domestic outlet is 240V fused at 13A, which is nominally 240*13 == 3000VA.
If you you divide this 3000VA/25V = 120Amps.
These values are for explanation only.

How many Amps do you want at 25Vac? What do you plan to use the 25Vac for???
Look at the fuse box near the incoming mains supply, check the fuse ratings.
Do you have any domestic appliances that draw a high current?
ie: heaters, cookers, etc.

Eric

 

i'm sorry im not on the same page as you in electronics.

i guess i need atleast 8 to ten amps at 25 volts. this is going into my car powered by a 115 voltage inverter.

 

i have used a transformer with an output of 5volts @ 20 amps. so it is possible, but it's not really possible to rewind the transformer, as you wouldn't be able to fit all of the windings in the core, higher current means thicker wire.

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hi,
For a 25Vac at 10A, you need a 250VA transformer.

What are the details of the 115V invertor.?

Things...
Its not just the transformer windings that limit the VA, the 'magnetic' circuit has to be capable of creating/carrying the required VA.

Eric

 

I hope it's a big invertor, 10A x 25V =250Watts, the inrush current(turn on) will be many times greater.

 

my inverter is 600 watts. was you guys saying something about using a 250v transformer?

 

Ok so you have a 12V source (Your car battery) and you ultimately want 25Vac at 10 amps? Or are you going to turn that 25Vac into DC? What exactly are you planning on powering with this?

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i'm after 25v DC or AC atleast 8 to ten amps in my car, i dont care if its ac or dc, as long as its 8 to 10 amps.

i need 25 volts with amps. don't care if its ac or dc.

 

What you need to build is a boost convertor:
http://www.linear.com/pc/productDeta...03,C1042,P1597

Wrong output voltage, but it could be modified for 24V fairly easily.
Or buy one, though they can be pricey due to low volume production:
http://www.ict-power.com/product05-display.asp?ID=155
Cheaper ones at $140:
http://www.powerstream.com/dc24.htm

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Maybe I am lost but I think Triple-Access just want to know how much current he can get at 25 volts when the power comes from a wall outlet (110 volts ac).

I find that 1000 watts is about all you should pull from a 110 volt outlet. Hair dryers may pull 1600 watts. Some loads like the hair dryer and a light bulb call pull power up to the limit of the breaker. Computer power supplies do not pull power efficiently and will pop the breaker at about .7 of the rating of the breaker.

1100 watts = 110 volts and 10 amps into the transformer.
1100 watts = 25 volts and 44 amps out of the transformer.
It depends on how you convert the 25 volts AC to DC but I think 30 to 50 amps is all you should get from a 110 volt outlet.

I hope I answered the right question!

Digikey.com has a 24 volt 7.3 amp transformer. 24X7.3=175 watts or 175VA You could use 2 or more transformers to get more current.

“can i find or how do i make this transformer???” Yes a transformer can be hand made and I do that but you are not going to with out much more experience.

When a transformer gets hot when you are using it beyond it’s rating that means you need a bigger transformer.

 

You dont care? Why not? hows about telling us about the application if you are serious about getting help here.

 

Is this for powering incansdescent lamps?

If it's to be used in your car why no go for a DC to DC converter? That way you need neither an invertor or transformer.

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