Stepper Motor M42SP-6NK Voltage Rating

When reviewing the spec sheet for the subject Mitsumi motor, there are specs for both 12V and 24V. My questions are:

(1) Where two different motors sold or does this suggest a range for the M42SP-6NK6NK, and

(2) The spec sheet for this motor indicates each phase rated at 2.0 Amp, 1.1 Ohm resistance, and a Rated Voltage per Phase to be 2.2. How does either 12 or 24 voltages correspond to the latter specifications? It seems to me the spec sheet implies I need a 2.2 voltage source that capable capable of delivering not more than a total of 4.0 amps (2 amps per phase).

This may have been answered by Robin2's post in December of 2014 which stated "the rated voltage was irrelevant, it was maintaining the current below the maximum rated value" was the parameter of concern. I've thought about this last question considerably and can't make logical sense of the numbers, so I would greatly appreciate someone confirming my understanding of the Robin2 post or explaining the conflict between voltage source range and maximum phase voltage.

Post a link to the datasheet for the motor and we may be able to help.

The low voltage is what you get when you use Ohm's law to calculate the voltage from the permitted current and the coil resistance.

A stepper motor is driven with short pulses of current and it would only present a simple Ohm's-law situation when it is stationary.

When you use a specialized stepper driver and set its max current to suit the motor the driver ensures that the current does not exceed the maximum. In any given pulse the higher voltage allows the current to reach its permitted maximum more quickly in opposition to the inductance and back-emf of the motor.

...R