# Hall Effect Sensor Positioning!!!



## Robbievl (Jun 22, 2009)

Hi,
I'm working with a 'custom' built brushless dc motor and have been assigned the task of getting it to work... don't ask why haha
I have been investigating different controllers and the one which seems most relevant has been the Kelly KBL48101.
The motor is designed by having the copper wave windings as the stator and the magnets as the rotor.
The motor has 16 magnets in total, that is 8 pole pairs. I have attached a picture which shows the placement of the magnets.
I'm not 100% sure how this controller actually works, but i believe that there are 3 inputs into the controller for hall-effect sensors.
So referring to the picture I attached, I was just wondering if anyone had any idea about where we should we position our hall-effect sensors in order for the controller to work and drive the motor.
I have heard that electrical signals repeat every 360/(magnet poles), so in our case does that mean we should have hall effect sensors every 45 degrees?
Thanks a ton!
Robbie


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## Amberwolf (May 29, 2009)

If you don't know how the controller is going to expect the signals to come to it, you can't place the hall sensors. There are multiple ways to setup these sensors, and they have to be where the controller expects them to be or the phasing won't be right and the motor won't work as it should (if at all).

You'd better get with the controller designer and work together to find out what your sensor requirements are.

That said, there are standard separations for where sensors typically go, if you look up common controller chips for BLDC motor control you can see what these are. Just keep in mind that if you design your motor in a way different from the controller, they're not going to work together.
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CurvyLadyLips


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