Understanding Residual Flux and Inconsistent Rotation in Stepper Motors

[sandy.bridge]

Quick question: I have a stepper motor that is 0.25 degrees per step, and so 4 steps is required for a degree. When we pump 20 steps into it, it moves 5 degrees. However, if we go to pump another 20 steps into it right after that, it does not move 5 degrees. Is it possible that residual flux is preventing it from fully rotating after the initial rotation?

An example of what will happen is as follows:

pump in 20 steps: get 5 degrees of rotation
pump in 20 steps: get 2 degrees of rotation
pump in 20 steps: get 5 degrees of rotation
pump in 20 steps: get 2 degrees of rotation

and so on
...

It seems to be consistent in that sense. Any clarification or insight would be appreciated.

 

[AR01075]

Sometimes if you try to step it too fast it will skip steps. Also, you may need to ramp up the stepping speed because the motor can't go from zero to maximum speed instantaneously.