You have several options. A 1 hp single phase motor is a simple and fairly cheap replacement. Just match pulley diameters and get the same rpm motor. Or, you can make or buy a rotary phase converter, consisting of a larger 3 phase motor (thaN that which you are driving), some motor run caps, switches, and a housing for it all. Look at other areas to find oodles of info on such a design. If the 1hp motor is the only 3 phase motor you plan to drive, I would recommend just to change out the motor. The so called static phase converters I wouldn't recommend. All they are is a pseudo-rotary phase converter, by adding caps to YOUR driven motor. You only get about 66% of the motor's output due to driving only 2 phases from the grid. Good luck, it's an easy task. You can find some f airly cheap motors at harborfreight.com, but note that they are often under-rated. Seems many motor and vacuum cleaner manufacturers get away with lying these days. Figure an amp draw of ABOUT 1000 watts, or 8 amps, at 120v, per horsepower, and that should tell you how much they are lying. Good luck.