Question re: step-up transformer watts
 

Hello, fellow vintage machine lovers.

My Lady Nora, is a Great Britain 222K featherweight, she has a 220V 3-prong plug and came with a 2-prong converter for our US 120v plug-ins which only runs the sewing machine at a slow speed. I know I need to replace the prong converter with a step-up transformer but there are different versions with different watts. I want to be careful to not damage the 230V-250V 0.25amp motor with more watts than needed. If anyone here has dealt with this scenario, I would appreciate your guidance. How many transformer watts do I need?

P (watts) = I (amps) * V (volts), so you need a minimum of a 60 Watt transformer. However, the amount of power used by the machine will be determined by the machine's resistance, rather than the size of the transformer. The transformer will just determine how much power is available. You don't want to fully load your transformer (best to keep it under 80% of the rating).

I'd get a 100 or 200 Watt transformer, which will keep it under the 80% utilization recommendation.

We have just moved from Hungary to the US, and we brought our digital piano with us. We faced the same issue as you do, with converting the voltage from 220V to 110V. I contacted the piano maker, and they recommended this step up-step down converter: http://www.voltageconverters.com/itemdesc.asp?ic=VC100W. I ordered it (not expensive at all), and it works great! You don't even need the plug adaptor, as you plug your machine into the converter, which then plugs into the wall. I hope this helps.

In addition, this converter allows you the choice of what voltage you have that needs to be converted. In your case, you would choose the highest voltage (you put a two prong pin that comes with the converter into the opening of the Featherweight's voltage). You choose the 110 volt output that you need for North America. You plug your machine in with the original British plug into the converter, and the converter gets plugged into the wall. Voila!

Thank you for responses, I tried a 100W transformer ordered from EBAY and it seems to function as it should now when it's switch is set to 230V.