3-phase variable reluctance motors

I've got my little grubby hands on a few of these, and I was wondering
what they might be used for.

The rundown:
Superior Electric Slo-Syn stepper/synchronous motor
65 oz-in holding torque
24 step/rev
36V operation, 2.5A

These things have 4 wires...one is common, the other 3 go to the coils.

What gets me is that the shaft is so free-spinning, not at all like the
steppers I'm used to.