According to the schematic on page 6 of the motor datasheet, ( I think ) the capacitor is a run capacitor, as described on this wikipedia page. At the top of this page it is said: "A motor capacitor [...] is an electrical capacitor that alters the current to one or more windings of a single phase AC induction motor to create a rotating magnetic field".Induction motors cannot be synchronous motors, right? So that would mean my motor isn't a synchronous motor...Also I know from the datasheet that my motor has 2 poles (the "2" in the motor designation key is the number of poles).
Yes its an induction motor with a run capacitor. It is not "dimmable", don't even try.
You may or may not get away with slowing it down by reducing voltage FOR A FAN LOAD as the fan torque drops off very rapidly with speed