H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
H02K—DYNAMO-ELECTRIC MACHINES
H02K19/00—Synchronous motors or generators
H02K19/02—Synchronous motors
H02K19/10—Synchronous motors for multi-phase current
H02K19/12—Synchronous motors for multi-phase current characterised by the arrangement of exciting windings, e.g. for self-excitation, compounding or pole-changing