Sorry. New here. Should be in support forum. For a hall effect 24V sensor motor,
A. What magnetic poles are suitable in this application
B. How slow can it run? Is it correct that Hall motor only go down to SLOW but not near zero speed of 0.5 RPM?
C. What other parameter I need to match a motor. Thanks
The pole pairs are dependent on the motor. You can try finding them with the instructions here
Hall motors can go down to zero speed, but as speed decreases, velocity control fidelity is significantly reduced due to the low resolution of the hall sensors.
Other parameters you should look at are just desired continuous torque and speed typically.