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Unread 06-05-2012, 22:35
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Re: paper: Window Motor Lockups: Causes and Solutions

Quote:
Originally Posted by Al Skierkiewicz View Post
Larry,
I believe the problem manifests itself when there is enough backlash in the system that the motor can vibrate with the output current waveform generated by the Jag. Systems such as steering in a crab drive system tends to damp any vibration that might occur. From those that have reported to me or here on CD it would seem that more than half of the teams that use the Jag/window motor combination experience the problem.
Noted. Most of my information was based on random noting from threads over the past year or so. The sad part is that most of the details regarding the cause of the lockups is based off of observances...


Quote:
Originally Posted by Al Skierkiewicz View Post
As reported, the difference between the left and right hand motors has more to do with the wire size the armature is wound with than actual performance. The lefthand motor getting significantly more use in standard operation then the right.
IIRC most of my knowedge regarding that left-right issue was from one of your posts. Ironically, during the 2011 season, 1747, the team I was on before my family moved, asked me why their arm based on a left-right design was overheating so much... It was bewildering at the time; hence why I thought it was worth mentioning as a potential cause.

"Performance" may have been the wrong word; I was trying to imply that the motors weren't quite compatible with eachother so to speak. Any suggestions on a better word or phrase to use?


Quote:
Originally Posted by Al Skierkiewicz View Post
Nice job on the paper and the pictures it contains. This should allow more teams to overcome this small shortcoming by removing the pins. I would suggest you add the length of time this operation would normally take. Since it is so easy, more teams would take your advice and remove the pins.
TBH I never timed the process. I have only performed the procedure twice, both times as a student in 2011. The work on the motor was mostly done by a student that I was instructing. However, since I did do some of the work (as a demonstration), I was sure to make sure the motor used was a dead one; I wanted any motors that would see use worked on by the students.

Since I currently am not a permanent mentor (the photo shoot was by special request), I personally do not forsee myself getting a chance to time the job. Perhaps other teams that perform the procedure could post about how long it took them (I'd take a guess but in that shop, time flies).


Quote:
Originally Posted by Al Skierkiewicz View Post
I would suggest that teams also keep the pins in a safe place so they can reuse them if needed.
I hadn't thought about that... Noted. I may add that to a future revision.
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1747 Harrison Boiler Robotics 2008-2010, 2783 Engineers of Tomorrow 2011, Event Volunteer 2012-current

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