Control circuit for a self-starting electric motor

摘要

The invention relates to a self-starting electric motor assembly of the type having a permanent magnet rotor, a stator with two windings and electronic switching elements for the windings controlled by switching signals occurring in push-pull and derived from control signals of a sensor detecting the angular position of the rotor. At standstill and for normal running operation the magnetic field distributions between the stator and rotor are selected in a known manner, so that the rotor assumes an angular position which is displaced in relation to the neutral position as an aid to starting and so that the switchover occurs at an angular position ahead of the neutral position to provide greater efficiency for the running operation. A modulating circuit is provided which causes the rotor to be "wound-up" in the reverse direction during starting so that the rotor will gain a substantial starting momentum in the driving direction upon termination of the wind-up and the initiation of the normal running control signals.