PXI-7358 Brushless Motor Control, Hall Sensor Problem

[RyanN]

The motor is a Cyclon CY PR 32.  It is intended for use with model RC aircraft.

I have checked the sensor outputs with a voltmeter to verify that they are working correctly.  When the magnet is under each sensor, the respective sensor outputs 5V relative to ground.  When the magnet is moved away from each sensor, the respective sensor outputs 0V relative to ground.

[AnalogKid2DigitalMan]

Ryan:

I was hoping to find some technical data regarding the halls on Cyclon's site, but came up empty handed. All I can figure is that you may have the hall phasing mixed up.

I'm not familiar with the PXI-7358, but I presume it has inputs labelled Hall A, B ,and C or Hall 1, 2, and 3. Does the motor have the specific halls labelled?

BTW, that's a pretty impressive motor in terms of power/weight ratio

[RyanN]

The Cyclon motor did not come with Halls installed already.  We mounted our own Hall sensors to the motor support bracket.  Since the motor is primarily intended for the model RC market, and RC pilots typically don't need these sensors, they were not included on the motor.  Is this a problem?  I set up 3 sensors on the bracket 120 deg apart from each other, and have a magnet mounted in a disk on the motor shaft.  This magnet triggers these sensors as it passes by.  I have verified that that is the case.

It IS a fantastic motor in terms of power/weight ratio.  Also, it was very reasonably priced (~ $30).

-Ryan

[Brian_Beal]

I think that could be your problem.  Each halls needs to be on for 180 degrees of the rotation and to be spaced 60 degrees apart, I believe.

[AnalogKid2DigitalMan]

Chapter 2 of this document discusses hall timing configurations, I think this is the root cause of your issue.

http://www.ni.com/pdf/manuals/371060b.pdf

Hope it helps.

-AK2DM

[RyanN]

After studying those Hall diagrams a little more closely, your explanation sounds like that is the way to go.  I'll try to figure out something with that configuration.  Thanks for all the input :).

-Ryan