DC Brushless motor Controller

Thread Starter

gusmas

Joined Sep 27, 2008
239
Hey

I understand how a normal DC motor work, but now the DC brush less motor I'm interested in has 3 phases, configured in star topology. Now the document I have comes from Microchip (Document name posted at the bottom). I understand by powering certain segments the rotor will be moved accordingly. Can I assume that the current stator position (North Pole) is represented by the hall sensor combination in table 2 (Using Figure 1 as the reference)?

AN857.pdf
 

Mark_T

Joined Feb 7, 2012
47
I can't see the table, but have seen many before and the basic answer is yes....but you may find depending on your motor windings and magnetic poles that you have to repeat the pattern twice for one complete rotation. So you could be 180 degress out.
 

Thread Starter

gusmas

Joined Sep 27, 2008
239
The thing is I dont understand really how that table comes up with its values, because according to the table 2 to move in a clockwise rotation those phases has to be put after one another, so why is it forcing the rotor to go from 001 (Phase 6) to 010 (Phase 4)?? and not from 001 (Phase 6) to 101 (Phase 1) which is actually clockwise???
 

Mark_T

Joined Feb 7, 2012
47
Are you just energising one coil manually? If so this thing moves fast and has overshot the phase you are looking at and is stuck 180 degrees out? maybe.
 

Thread Starter

gusmas

Joined Sep 27, 2008
239
I have no circuitry yet just researching it but want to understand first before i blow something up
 

THE_RB

Joined Feb 11, 2008
5,438
Most people buy an brushless motor controller module (sold for radio control model use).

It will do all the work of driving the motor and current limiting etc, and all you need to do is feed it a control pulse width 1.0->2.0mS like an RC servo.
 

zaw

Joined Feb 13, 2012
3
I don't know much about BL motors ESC in details but I played with enough Helicopters to know that if you reverse Any 2 of 3 wires the motor will spin reverse.
 

shortbus

Joined Sep 30, 2009
7,330
I don't know much about BL motors ESC in details but I played with enough Helicopters to know that if you reverse Any 2 of 3 wires the motor will spin reverse.
This is because a BLDC motor is really 'three phase', this is the also the way a three phase AC motor is reversed.
 
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