Something about the sound of a synchronous motor starting up. I just finished building my 30 hp RFC 2 pole pony. ( 2 pole was a mistake) loud fan. I use it in my home shop and now I have enough power for my 12hp 120 falling Kellogg air compressor. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Kd6FkqM3KbQ.html
