Why are there identical motors but with a different current?
A single motor can be realized with different types of stator winding even maintaining the same external dimensions and the same static torque (Holding Torque).
The reason why different windings are realized is to optimize the functioning of the motor at different speeds.
If the motor is used at low speeds it is possible to realize a low-current winding, while if the application requires high rotation speeds the winding will have to be of high-current type, otherwise the motor will not be able to supply a significant torque at high speeds.
Consider in fact that the torque supplied by the motor depends on the magnetic field generated by the stator and that the same magnetic field can be obtained both from a winding with a high number of turns crossed by low current and from a winding with a few turns crossed by higher current. In the first case the inductance and the back electromotive force will be greater than in the second type of winding. To obtain the rotation of the motor it is necessary to continually reverse the sign of the current applied to the motor windings and it is evident how the first type of winding, the one with high inductance and back electromotive force, is not adequate for high rotation speeds as both elements contrast the inversion of the current in the windings. On the contrary, a winding with a low inductance value allows a better current control with better performances of the stepper motors at high speeds.
Our motors are featured with low inductance values to always grant high performances in every type of application.