Starting and accelerating torques
The characteristics of these torques are closely
allied and will be discussed together. Five
individual torques contribute to the turning effort of
a synchronous motor during starting and
accelerating. They are produced by:
1. Amortisseur windings
2. Field windings
3. Hysteresis in pole faces
4. Eddy currents in pole faces
5. Variation in magnetic reluctance
Of the five torques, only the first two are
significant during starting and accelerating, and
only their characteristics will be discussed here.