All stepper motors suffer from a 'strange' phenomena, particularly al low speeds, that can cause a dramatic lost of torque or even a stall of the motor itself. This phenomenon regards the 'resonance' of the motor, a particular frequence where the motor starts a desyncronization because its natural oscillating frequency has been reached.
Naturally this problem will cause a serious step loss of even the complete stall of the motor even if we are dealing with new motors, very well powered or well driven by the controller.
Using a step generator we can easily see and even touch (by hand) this phenomenon connecting a stepper motor to a single driver/controller and increasing the frequency very slowly. There is a point (usually between 20-60 hz) where the motor enters in resounance, can be stopped easily even using a finger and sometimes even stalls by itself. That particular frequency must be avoided.
To solve this trouble we can:
- avoid to use that particular frequency;
- use half or microstepping.
