1-1/2hp on 120V is about the max you can do on a 20A breaker..I have a 2hp on a 120V 20A breaker and it trips quite frequently on startup..I find the 120v tandem 'double' breakers trip more frequently than a standard single slot breaker. I don't know what your budget is but you also use a small (<3hp) three-phase motor and drive it with a 220v single phase input VFD which gives you 3 phase output but the motor speed and direction is controllable from stop to full speed with a knob.That might work out great on the roller. I've had good luck with the Hitachi VFDs,they are one of the few that has a 3hp VFD that will run on single phase input 220v..The Chinese made ones on eBay aren't too bad either, I tried a 2hp VFD on a drill press, cost about $100, it had difficulties in programming it, but the tech support all the way from China via email was surprisingly good.That VFD drive been good so far and gets just about daily use.