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I have a small BLDC motor and I would like to use it in a project of mine.
Is there any relation between the minimum angle (precision) I can move the motor and its number of poles?
How could I calculate the minimum step I can move the motor, considering that it has 12 poles?
Thank you in advance for your answers!
The motor itself has virtually infinite resolution (minimum angle that it can be moved). Practical resolution is limited by the controller, which has a limited number of PWM steps.
Having more poles is better because the controller's resolution is relative to each pole. The minimum number of poles is two, which produces a full revolution from 1 cycle of 3 phase drive. Your motor has 14 poles so it has 7 'electrical revolutions' per mechanical revolution, making its effective resolution 7 times higher.
Precision is limited by random mechanical effects such as bearing friction and slop. Accuracy is affected by nonlinearities in the motor's electromechanical response. If run open-loop the rotor will not move by precisely equal amounts per step. So while you might get eg. 360 steps per revolution, they won't all be exactly 1° apart. Torque ripple also occurs as the motor rotates, so any load will cause the rotor to be pulled off position by varying amounts.
Gimbal motors are normally run closed-loop with gyros and accelerometers providing feedback, which compensates for torque loading and nonlinearities in the motor.
