How can I make a step up transformer from 6V to 120V with a current rating of about 300 mA?

Question

I have a low AC supply of 6V and want to do a step up transformer to get 120V. It should use a maximum of 300 mA. I've been trying to make it with nuts, bolts, and 26 gauge magnetic wire, but so far I have failed. Any ideas?

Answer 1

300ma in which winding? Assuming the 6v one, this is a small but not tiny transformer.

There are a lot of 120v to 6.3v 1 amp transformers around, they used to be used for vacuum tube filaments.  Get one and use it backwards.

Answer 2

120 volt to 6 volt transformers are very common. (perhaps a doorbell transformer) Just buy one of those and run it backwards.  Supply the secondary windings with 6 volts and you should get about 120 volts from the primary windings.

If you want to do it yourself, you will need a ferromagnetic core (rectangular) and will need to wind varnish insulated solid wire in a 20:1 ratio.  The windings need to be in close proximity.  The number of turns is to some extent driven by the gage of the wire.  A 300ma transformer won't be that big.

Answer 3

You want to multiply by 20, right?  That's the same as dividing by 20, backwards.

Get a mains transformer  (i.e. with a primary of 240V)  and a secondary of 12V.  Feed 6V AC into the secondary.  You will get 120V AC coming out of the primary.

Transformer cores generally are made out of many thin sheets of steel, insulated electrically from one another.  Otherwise, you can get currents induced in the core instead of in the windings.  You also have to have enough steel present for it not to be completely saturated with magnetism during one "peak" or "trough" of the supply current.