Quote Originally Posted by Phil Gravett View Post
Not sure what unipolar means. ?
Unipolar - current flows through coils in one direction. Generally a unipolar motor windings have a centre tap connected to one side of the supply (usually +ve) and the ends of the coil windings are conencted by the driver circuit to the othe side (usually -ve or ground)

Bipolar: both ends of the coil are driven by the driver and current flows in both directions through the coil.

Bipolar gives higher torque/speed