136 Industrial Robotics Fundamentals Copyright Goodheart-Willcox Co., Inc. N S N S N S N S S N Rotor Stator poles Stator coils Goodheart-Willcox Publisher Figure 6-18. A single-phase synchronous motor has a simple construction. The rotor turns without making direct contact with the stator poles. Stainless steel shaft N1 N5 S4 N6 S3 S4 S8 S N22 Stator Housing Rotor Rotor teeth Superior Electric Co. Figure 6-19. This illustration shows the stator layout of a two-phase synchronous motor with four poles per phase. Poles N1 to S3 S and N5 to S7 S S represent one phase. Poles N2 to S4 S and N6 to S8 represent the second phase.