Re: Drive Glitching

Original post: https://vexforum.com/t/drive-glitching/25353/1

First thought: You are tripping the breakers in the cortex and the power expander.

A couple of questions:
How heavy is your robot? If you are using all steel on your robot, you will trip the breakers. The power expander has one breaker, and the cortex has two, ports 1-5 and 6-10.

Are the motors 269/393 high speed/393 high strength? If your drive is powered by 393 motors that are internally geared for speed, try regearing them to torque.

I had very similar issues to this at a competition today. My robot is only about 10lbs. Fully aluminum drivetrain and lift arms with 4 steel towers for the lift. 4 393 motor drive, geared internally for speed. Could the gearing really be why the motors stalled out so often? If so, how do you think can we avoid this without changing the gearing back to torque? Is a 6 motor drive necessary if we want to maintain the internal speed gearing?

I really doubt your gear ratio is too high. My guess is that you have a ton of friction in your drivetrain. We ran three robots today at 1.6:1, one of which is easily 15 lbs. None of them had any problems with burning out drive motors unless they got into a pushing match.

A light robot like this should easily be able to handle 4 motors internally geared for speed. I posted some tips and solutions for this during Sack Attack which might help you out:
https://vexforum.com/showpost.php?p=319330&postcount=4
Let me know if you have any questions about anything in the post.
Good luck!

Our team had this problem as well during our competition. We tried switching motors, using different batteries, not connecting to the VEXnet tower, etc… After no more than 30 seconds into the match, the drive would stop working, after that, only our intakes and lift would work. In one elimination match, 3 of the robots were immobilized in the same way. It became very frustrating as it happened to us in EVERY match (not an exaggeration), and as soon as we would use it off the field or with a wired connection, it worked perfectly fine. Our team thought it may have been the interference from the other VEXnet keys, but we couldn’t support that with any evidence.