Step down transformer voltage


2010-12-16 10:47 am
Hello all

Newbie posting here. There's definitely some useful discussion going on here, (speaking as a non-techie muso, though still using a lot of old analogue hifi & recording kit).

My problem is with a new bit of gear which I got from the US, ie needing a transformer for 240v for here in the UK. It's a vintage vibraphone, which I use ok acoustically, but the resonators have a motor similar to a turntable motor, using a belt to turn the paddles in the tubes.

The motor has no rating visible, but I'm guessing it is a similar size to that of a classic turntable such as the Garrard 401. The belt is shifted manually to achieve different speeds. The transformers I've seen begin at 45v, then 100v. I'd like to set up with the right one and not burn the motor out, as it is the original, and not easy to replace.

Any technical advice would be gratefully received!

you can use an isolating transformer (= an ordinary transformer) with 230:115Vac primary to secondary.

Or you can use an autotransformer again 230:115Vac. The big disadvantage of the autotransformer is that it does NOT isolated from the mains. The outputs of the auto transformer MUST be treated as if all were LIVE.

The autotransformer is cheaper and lighter and smaller.

If you have an existing 115+115:any secondary voltage, you can convert this to become an autotransformer.
The VA rating of the 115Vac output will be ~half the VA rating of the transformer.
I suspect you need very few watts to drive your 110/120Vac equipment. Check to find the required power.