On Mon, 8 Nov 1999 20:40:01 -0700 Keith Causey writes: > Also I couldn't find a ground return for the 3 coils so I just > made one > (they were connected - just not routed anywhere) Don't connect the center point to ground. When it's working properly, current flows into one coil and out the other two. Having a ground can cause a significant DC current to flow if there is any imbalance in the drive signals. Without the ground you can use a single polarity of power supply and the center point will float up to the average voltage applied to the motor (about half the supply voltage). Also it is generally necessary to drive the coils in proper sequence based on feedback of the position of the rotor. That's what the Hall effect sensors under the rotor are for. Without this feedback it is hard to get the motor started. Applying constant- frequency sine waves to the coils with the rotor stopped will just make it sit and hum (or sing, depending on the frequency). Why not use the driver IC that came with the motor? It does everything you want except they usually drive the coils with square waves, which may cause slightly uneven revolution. Unless you're trying to build a really precise machine it won't be noticeable. These chips almost always take a DC voltage to control the drive to the motor (either linearly or PWM). In a floppy drive, the DC voltage is developed with a PLL circuit between a crystal somewhere and the frequency generator coil printed under where the edge of the rotor turns. The PLL circuit is usually in the same chip as the motor driver. ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj.