V-I curve for Stepper Motor
A velocity-current-Graph does not seem to make a lot of sense to me. It is possible to create a graph like that, if the input voltage is fixed, but in power applications, steppers are usually used in constant current configuration. Without seeing the datasheet, I can not be sure (I don't know whether I can with seeing the datasheet), but I typically raw motor datasheets list per-winding currents, while datasheets for drivers might list input current (total) or output current (per winding).