Voltage converter

Deeper consideration with Net Surfing informed me of a better way to control Alternative Current for our vacuum motor to set the activating voltage at the most adequate value for the work.
Though I imagined conventional way to do that by means of linear voltage transformer having been called as voltage convertor, I came to the conclusion that very simple and cheap circuitry could attain the purpose with semiconductor, modified thyristor, Triode Alternative Current Switch, TRIAC. This fact encouraged me to change planning now.
I'm going to assemble some electric parts with safety circuitry because my laboratory is situated at the place 20 minutes subway from Electric Parts Town Nipponbashi Ebisu-cho.
Reporting about this later.