Complex sentence: These have a rotor consisting of a solid steel casting with projecting (salient) toothed poles, typically less than the stator poles to minimize torque ripple and prevent the poles from all aligning simultaneously--a position which cannot generate torque.
Split into simpler sentences: These have a rotor consisting of a solid steel casting with projecting (salient) toothed pole. Typically there are fewer rotor than stator poles to minimize torque ripple and to prevent the poles from all aligning simultaneously--a position which cannot generate torque.