is it possible to connect 220v at two ends of a autotransformer that have only one coil and use 22v from two terminals from inside points without having a common terminal? like showed on the diagram. will it be safe? thanks.

 

Autotransformers aren't safe by themselves, because they don't provide isolation from the mains.

If you want to use an autotransformer, you'll also need to use an isolation transformer.

 

its not that safe but can it be used in that way?

 

Yes. Do I recomend it, only if I know capabilities of person. Electric clothes dryers are safe as long as they are in good repair and back cover is in place.