Anybody knows about the control of BLDC motor using two hall sensors and how to find out the exact mechanical angle between the hall sensors

[Ann1]

We know that. when using three hall sensors, the 3 Hall sensors should be spaced across the printed-circuit board (PCB) so that they are 120° electrical degrees apart. From the center of the motor axis, the number of degrees each sensor should be spaced equals 2 / [number of poles] × 120° i.e. for 6 pole motor,if 1 sensor is placed at 0°, 2nd sensor is placed 40° rotated, and 3rd sensor is placed 80° rotated.

Similarly, i have seen a 8 pole BLDC motor with 2 hall sensor . For controlling with 2 hall sensor, what should be the proper placement angle? How is it calculated. . What will be the control logic ? Is it estimating the third hall sensor signal from the existing signals?

[cedric H]

Hello Ann,

This is an interesting question, I have never encountered such kind of motor. Could you share the motor reference ?

Are you sure that your motor does not have an encoder instead ? encoder requires only two wires.

Thanks

Cedric