Paul has given very good information, and will be of great assistance for the applications you refer to.
I was wondering a few things.
[*]Any AC inputs, or AC coupled to DC,
[*]What polarity will the three voltage sources be at any given time,
[*]Will the Motor's input polarity ever change,
[*]What type / level of components are to be used for monitoring / control.
For #2 above, will the inputs be "+" or "-" (in respect to ground)? Will any input be the opposite of another input?
Per #3, will the power supply for the Motor be a 3 wire DC type (+ / GND / -), or will the Motor's input be sampled from another source?
Per #4, what level of "Tech" do you need?
May be simple - like with all passive components,
May be more complex - like with Opamps and/or discrete components,
May be really complex - like with interfacing capabilities.
Sounds like fun!