After reading many contradictory accounts of the "proper" method, I would like to clear it up: what is the correct method for driving a 4-wire, star configuration hard drive motor?
What I have observed people/companies doing:
- Driving the motor using 3 wires and not connecting anything to the Common wire.
- Putting half-bridge drivers on all 4 wires.
- Setting Common to GND and driving the other 3.
- Setting Common to V+ and driving the other 3 open-drain.
Now, I recognize that there may be multiple ways to drive it, but what is the intended method? How are they SUPPOSED to be driven?
For your reference, I am planning to use the HDD motor to build a variable-speed precision driver, which will have optical feedback (i.e. optical tick marks on the platter rim) for the speed control.