Who made the extractor, does it have a two belt drive system, more info would help. But if it is one of the older Maxants type with a two belt drive system with a large thumb screw clutch on top between the two belts then
I would say you need a fractional horsepower motor 1/3HP or 1/2HP 1725RPM 110volt single phase.
If it is a two belt system and you didn't get the motor drive pulley with the extractor then get a pulley the same size as the small one on the clutch shaft. To reduce a 1725RPM to spinning speed the setup would be approximately motor 2" pulley to a 4" on the clutch shaft, from the 2" on the bottom of the clutch shaft to the 4" on the spin basket shaft. This would give you approx 430RPM. I never run the basket at full speed so as not to blow out a frame but adjust the clutch thumb screw to what I think is around 275 to 300RPM. I start my spin at a low speed,maybe 100/125RPM to reduce weight on one side of the frame--then turn the frame and run it up slowly up to about 300RPM --then turn frame and run it up slowly to about 300RPM to finnish. I have only blown out one frame since I started and this was only because I forgot to turn the frame before bring up to faster speed.
Hope this helps--sorry for being so long winded