5.2. Determination of time and pulse interval

5.2.1. Considerations on the characteristics of pull-in

It is easy to use Equation 5.1 for the performance analysis of the stepper motor when starting from the current transient, the movement of the rotor and the motor torque must be taken into account for computation. Instead, the ability to start the stepper motors can be studied using the characteristics of pull-in torque. These are based on various factors such as load and motor inertia and may vary depending on the method used to apply the load. Therefore we have to refer to the curves of pull-in load conditions until the engine is started. You have to assume that the engine be started and stopped without failure curves for pull-in given when f1 Hz pulse train is constant, as shown in Figure 5.24 (a), the pulse interval is determined by 1 / f1.

To compute the acceleration, it is advisable that the first pulse interval is 1/f1 as shown in Figure 5.24 (b), and from this moment happen a decreasing subsequence of intervals, providing acceleration and taking into account established features pull-out.

Figure 5.24. Click for a constant rate of acceleration steps.