Hello all, I am attempting to drive a spindle motor (the type used in floppy
drives) with 3 duty-cycle generated sine waves 120 degrees apart. The SX
generates these signals from a look-up table. These logic-level outputs are
converted to +- voltages with a comparator. This bi-polar output is then fed
into 3 totem pole amplifiers consisting of 2N3904's and 2N3906's. The
resistance of each of each coil is 4.6 ohms. It barely works. Voltages above
+-3 smoke everything and the positive side of the drivers gets distressingly
hot. Also I couldn't find a ground return for the 3 coils so I just made one
(they were connected - just not routed anywhere) What am I missing about the
way these motors are controlled? Thanks - Keith Causey.