I've done this with DC motors by determining the inductance and then computing tao = L/R where L is the inductance of the coil and R is the resistance of the coil.
Is there a best-practice way to determining the electrical time constant of a BLDC motor? How should I go about measuring the inductance?
I'm interested in this because for DC motors I have been following the rule-of-thumb that your PWM frequency should be greater than or equal to one over the time constant of the motor to mitigate the torque ripple, etc.
Thanks in advance for any help you can offer.