[ASK] Rewinding toroid transformer

[casiomax]

I got three 300VA toroid transformer from my father's junk box with a primary AC 117VAC. Here in my country we use 220VAC main AC. How to calculate windings for primary and secondary to convert this transformer primary to 220VAC and 18V-0-18V secondary?

can someone help me for calculation.

the easiest way is to use a step down transfmormer of course.

thanks

 

[ECM]

Use two of them at the same time and wire the primaries in series.

What are the specs on the transformers? Center tapped? Output voltage?

 

[casiomax]

sorry it was a 180VA transformer if my calculations correct,

primary is 117VAC, and 2x15VAC secondary 6Amp.