MY CNC sessions are now like laundry day....

[m_c]

I'm sure some people could, but jonathan has kind of over explained Hanks question.

Basically the 3V is the voltage you could permanently supply to the motor without it going into meltdown. At the rated voltage, the connected winding should draw the rated current.

You use a higher voltage to force the magnetic fields within the motor to change quicker. Ideally you calculate the required voltage from the motors inductance, but that's a figure that often isn't quoted, so the accepted figure is 4to20times the rated voltage to ensure a reasonable safety margin.
However, as you know the inductance of your motors, the formula is 32 * vL = VMAX, or 32 * 3 * 2.1 = 201V, which seems a bit excessive, and is why Jonathan has questioned the figures (could just be that the motors you've got are an older design with a lot of iron in them!).


If you want a clearer understanding of stepper motors, check out the gecko drive Stepper Motor Basics at http://www.geckodrive.com/ark-2/support.html. Mariss knows a thing or two about stepper motors, and is also good at explaining things without too much geekyness.