thanks for the hint. The HD spindle motor I just took to have something at hand to fiddle around with it. I think that I made a too simplicistic approach to drive a brushless Motor drive. I studied some comments on app notes and drivers that are built for driving BLDC motors. They come up with intelligent startup procedures to detect the position of the rotor without having hall sensors, or using DSPs to model the whole thing. But there must be a more simple method to drive a 1Watt motor..
I keep on searching.

Werner