Thanks for letting me know. Just tried it and it works for me, but will list the data here. Toshiba 3 phase, TEFC, 60 HZ, 1175 rpm, 230/460 V, 57/28.5 amps, 6 poles, max ambient temp 40 deg C, time rating-continuous, frame 286T, service factor 1.15
Never heard of a 6 pole motor being used for a RPC, but I don't know why it wouldn't work. I suspect the reason that they are not used is because they are not very common, and more expensive than a 4 pole motor.
I've built RPCs with both 3450 and 1725 rpm motors, and they worked exactly the same. A slower speed motor develops higher torque to deliver the same power as a higher speed motor, so the rotor will be heavier. I think that accelerating the heavier rotor puts more stress on the starter capacitor and that the heavier rotating mass helps when starting a run motor under load like a compressor or hoist. That's seat of the pants observation, not the opinion of a trained electrical engineer.