What voltage do you have your machine set up for? If it's set up for 220 volt 3 phase, then just take the fan leads to L1 & L2 for 220. Should be able to get it from the same taps your spindle inverter inputs are on.
Actually, it shouldn't matter what voltage you have going to your machine. L1 & L2 going to your VFD for the spindle should still be 220.
Richard