I have three 12dc/220ac. inverter i need to change input volatge to 48 .How can I do that please help me.

 

That will probably need a different transformer or a rewind of the existing one.

 

The inverter I have is 1500w .so what kind of transformer i need.

 

I have three 12dc/220ac. inverter i need to change input volatge to 48 .How can I do that please help me.

What makes you think it is even possible with the chips in the design you have?
You'll be far happier with a new inverter. Their design and construction is not a task suited for amateurs.

 

The inverter I have is 1500w .so what kind of transformer i need.

That all depends on the design of the inverter. Do you know the turns ratio for the existing part?
To raise the input voltage you need to reduce the number of turns on the secondary by about a factor of 4. Reducing the number of turns is easier than increasing the number of turns on an existing core.

 

To raise the input voltage you need to reduce the number of turns on the secondary by about a factor of 4. Reducing the number of turns is easier than increasing the number of turns on an existing core.

Unless something else is changed (frequency?) that is likely to lead to saturation as the primary now has four times its designed the voltage across it.

 

Unless something else is changed (frequency?) that is likely to lead to saturation as the primary now has four times its designed the voltage across it.

I never said it was a good idea, I was just trying to point out the difficulties of re-purposing a component without much in the way of knowledge about what you were doing. You point is clearly a killer, especially if you have no way to measure the result of modifying the transformer.

 

Have you considered whether you can find a suitable buck converter to step down the 48 volts to 12 volts? Sounds like your converter would need to supply about 150 amps(!).

 

Unfortunately there is no high current converter in local market in my country so please help me to how I can make 48 dc to 12 dc 40 amber converter.

 

Desiging somethign that can handle that kind of current will be a major project for most of the power supply engineers I have known. The application note at the link below will give you an idea of what the design would look like.

www.linear.com/docs/4362

 

I search for 1500w 48dc/220 ac in the market in my country unfortunately I didn't find sach one I want only I found 12dc/220 ac with 1500w .