Device for driving a single phase synchronous motor, especially for driving a pump in a household appliance

For reliable starting even when there is a relatively large load torque or inertia torque, the single phase synchronous motor (1) is connected to the supplying AC voltage power supply network (L1;L2) as a function of a rotor rotation position sensor (2), via an AC voltage switch, in particular a triac (7), when the rotor is positioned between a first indent position and the subsequent second indent position, only during the half cycles of one polarity, and subsequently between the second and the first indent position only during the half cycles of the other polarity; according to a preferred refinement of the invention, the reference signal for the supplying AC voltage which is to be linked to a signal from the rotation position sensor (2) is picked off directly via the switching path of the triac (7).