How can I figure out which phases in a BLDC motor to power without knowing how its wound? (programming.dev)

submitted 3 months ago by iliketurtiles@programming.dev to c/askelectronics@discuss.tchncs.de

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I'm making a driver for a small 15V, hall sensored, 9-slot BLDC motor I got off of AliExpress. It has u,v,w inputs. Three hall outputs and Vcc, Gnd for them. No datasheet :)

I understand the working principle: I'll have to use the hall sensors to figure out the location of the rotor, then power the appropriate windings.

Trouble is, I don't know how the windings for the three phases are arranged within the motor. So I don't know which pin to give power to, because I don't know which windings within the motor will then be powered.

How can I figure out where the windings are for each phase?

I'm guessing I've got to manually spin the motor and do some detective work with back-emf measurements and hall sensor outputs to figure this out?

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[-] dgriffith@aussie.zone 3 points 3 months ago

There is an empirical way of doing it - best one I've seen online so far is this:

AN186 - Brushless DC (BLDC) Motor Connections

[-] iliketurtiles@programming.dev 1 points 3 months ago

Thank you, will give that a go :)

this post was submitted on 12 Mar 2025

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