voltage changer

I have seen some washings machines can be used on 110V or 220V.
It need to be changed manually. There are some wire connection at the back to select required voltage. I heard that this is done by connecting capacitors paralle or series.
Can Anybody supply the circuit for it.

:?

Your help much appreciated.

The motors I am most familiar with are usually equipped with a tag or label that indicates the proper connections for the desired voltage. If it's not on the outside take the cover plate off of the junction box - it might be on the inside of the cover.