hall sensor placement in BLDC motor calculation

Hi Mahesh,

Placing Hall sensors (x3) between the motor phases 120 electrical degrees apart is usually best for detecting position of the motor. This introduces a 0 degree lead angle because the sensors are placed exactly between the motor phases. For advanced calculations, refer to this: www.ti.com/.../sbaa463

If you place the Hall sensors closer to one phase over the other phase, you will introduce a lead angle. Lead angle adjustment is used for larger inductance motors, because more inductance adds lag to the motor phase current compared to the phase voltage. By adjusting the sensors, the lead angle is introduced to delay the Hall outputs so it matches the electrical angle of the phase current. 

If lead angle is needed and the Hall sensors cannot be moved, you can add lead angle in software or through the driver (if using a DRV with lead angle adjustment). 

Thanks,
Aaron

Hi Mahesh,

Electrical frequency is always twice the mechanical frequency.

https://electronics.stackexchange.com/questions/187835/induction-motor-electrical-and-mechanical-angle#:~:text=Mechanical%20degrees%20in%20a%20motor,again%20equals%20360%20electrical%20degrees.

Mahesh Patel said:

A phase shift between Hall sensor  = (2*120)/(Number of Motor Poles). 

I am not sure about above. I'll forward your post to the sensing team to see if they know how sensor placement affects sensing lead angles/phase shifts. 

Thanks,
Aaron