To add a bit to DocTrucker's post, stepper motors are current driven. The driver supplies and limits the current. You increase the supply voltage to the drivers if you want to increase motor top speed (and torque). You do this primarily to overcome inductance of the motor.
The 'Rated Voltage' DocTrucker refers to and that is listed in many specs is a different voltage from what you refer to. The spec sheet doesn't seem to say anything about 80-250 V so I am not sure where that comes from. They do list a 500V rating which is probably the absolute maximum before insulation break down.
You notice that there is only a current rating in the specs rather than a voltage rating.
I would suggest forgetting to run these motors at 12V and going straight to 24V
