>If your load is light, you have to watch that your speed range doesn't
>include a motor resonance.
>Some motors have a very marked bite out of the speed/torque curve. If you
>try and start it at that speed, it will go buzz instead of whirr and
>nothing much will happen. Once started, the motor construction itself
>usually has enough inertia to overcome it.

This resonance effect is much less signifficant when using half step phase
drive sequence. But it needs twice more pulses to achieve the same RPM.

Josef