Timed current control for electronically commutated DC mo7ttttttommoor - uses commutation transistors controlled by selector circuit

摘要

An electronically commutated d.c. motor uses commutation transistors controlled by a selector circuit in turn controlled by a rotor position picup. The motor stator windings are star connected, and a free runnin circuit is provided for them. A current measuring device inserted into a connection the neutral point, carries both operating and free running currents. The free-running circuit of each stator winding (2-5) has a thyristor (10-13), whose control electrodes are connected through an inverter stage (18-21) to the output of the selector circuit to which a transistor is connected, belonging to the corresponding stator winding.