This article is concerned with position control of permanent magnet (PM) stepper motors and PM synchronous motors. We present, for the first time, some stability proofs which explain, under mild assumptions, why the most common control strategy used in commercial drives works well in practice. We stress that this successful control strategy has been used until now only on the basis of linear approximations. As in most commercial drives, we consider the design of a linear PID position controller intended for the mechanical subsystem and some inner electric current loops driven by linear proportional controllers which are introduced to cope with the electrical subsystem.