Motor behaving asymmetrically (MBL1650C with x812 tenshock)

I am in the process of testing my setup and noticed that my motor is not running at the same speed backwards as forwards. To test this I am running my motor in open loop control at 25% maximum power capacity. When I command +1000 I am using 15A~20A at 5000rpm, when I command -1000 I am using 1A~2A at ~5000rpm.

I suspect some of my windings have shorted, but don't understand why this would only effect reverse motion. Since I am hesitant to replace my motor I was wondering if anybody has had similar experiences before. So my question is; what could be causing this?

I originally suspected it might be my wiring, but my current setup: A to U, B to V, and C to W, is the only one that works well.

I have attached two screenshots showing the behavior and attached the controller configuration. I am running an x812 from tenshock through a MBL1650C at 24V with a 125A rated power supply. I will be using this setup as the power plant for my linear actuator.

Perhaps take a look at my video on setting up a brushless motor controller.

www.youtube.com/embed/9AkgJGngx3E?wmode=...toplay=1&fs=1&start=

Griffin,

Thanks, watching your video was one of the first things I did when I noticed my issue. I'm quite sure I've got the wiring setup properly though. I have followed your instructions twice and both times came to my current wiring setup.

I have also run the motor in most of the closed loop control settings and it works fine. It is just slower in one direction than the other. When I noticed the extra amp draw in open loop I figured something must be wrong.

With a normal DC motor I would switch the battery leads around. Then if the problem persisted in the same mechanical direction I would know it was my motor and not my controller. With a brushless dc motor I don't think this method of elimination is possible. If I switch A and C around should my motor run perfectly, but in reverse?

What is the version firmware you are suing on that controller?

The latest is 10/10/13

In the console tab, type in ?fid and it will report back the firmware and date. What is the date code of the firmware?

Griffin,

I just checked, my firmware does appear to be out of date. I will update it and report back.

?fid
FID=Roboteq v1.2 RCB350 05/25/2013

Regards,
Riewert

Griffin,

Updating my firmware does not appear to have relieved the issue.

I loaded the firmware, checked that I have the latest Roborun+ software, and reset my controller to factory default. Still the problem persists.

Do you have any other suggestions?

?fid
FID=Roboteq v1.3 RCB350 10/10/2013


Regards,
Riewert

Is there another motor you have available that you can try to compare with? Although unlikely, I'll have you check the calibration data.

In Console, send in the following commands.

~zpac
~zaic

It should report back 2 numbers for each.

These are just example values below
Zpac = 512:512
Zaic = 312:114

I will look into finding another motor to test with. Right now I don't have one lying around.

~zpac
ZPAC=512:512
~zaic
ZAIC=0:0:0:0:0:0:0

Regards

It looks like your controller is missing the calibrations for the Zaic values. Our sincere apologies. Please send an RMA request to This email address is being protected from spambots. You need JavaScript enabled to view it.

Please let them know that you need to send in the controller back for calibration.

Griffin,

Thanks for the help. I will let them know and get back to you when everything is in order again.

Regards,
Riewert