I need converter from 220V(European) to 110V for 9 amp(USA) appliance...
What kind of converter I should looking for and I understand I should look for 25% stronger converter than appliance..? How many watts converter,should be..?
Confused..
Thanks..
Rob

What kind of appliance is it? Does it have a motor or electronics?

If it is labeled for dual voltages it may just need to have a switch changed or a different line cord.

9 amps in the US works out to 1080 watts so you'd need a converter with a capacity of 1350 watts - unless it has a motor in which case you need to account for startup.

Some devices aren't going to work correctly due to our different frequencies either, 60hz in US, 50 in UK.

Please let us know what it is so we can give you the best answer.

Actuality it's a sub pump..

Ok, it has a motor. Depending upon what type of motor it has it may not run at the correct speed. So it could overheat or not pump as efficiently as it could.

I'm not sure if we can post links so just do a search on:
Step Up-Down Voltage Converters

You can get them in all sorts of wattages. I'd go with at least a 1500 watt if I could.

Hope that helps.

And one more question...
How I can know which one's are good..?
And long lasting..?
Thanks

Check out Voltage Converters - Power Converter Inverter Transformer (http://www.voltageconverters.com) and these guys http://www.220converters.com/store/c/1-Deluxe-Voltage-Converters.html

You mean sump pump? Or sub as in subwoofer.

Motors may need to be sized higher, as much as 2x. If they will be used on 50 cycles and they are rated for 60 cycles only then they may rub hot. Frequency will alter the speed of the motor.

For a motor you really want a step-down transformer. The 50hz/60hz issue also has to be addressed. You may be better off just buying a new sump pump.