VEXNet and Motor Problems

VEX V5 General Discussion General Forum
#1

We just went to a competition, and 15 seconds in the match started, our drive motors just died on us. They could barely move the robot, and sometimes it got so bad the robot wasn’t even able to move.

Originally, this only happened to the two drive motors on the right side, but soon enough the other side was doing it to.

The weird thing is, we replaced the motors, the micro controller, and the batteries were fully charged!:confused:

So does anyone have any idea why this is happening or what is causing this to happen? It never happened before when we were practicing with it. Only when we got to the competition.

#2

  1. did it work well in practice?
    your robot may have been too heavy to sustain your drive for extended periods of time

  2. did you aggressively use your motors prior to them “not working”? (pushing another robot, pushing a movable goal, having an autonomous that rammed for 20 secs, ect)
    this may cause the internal breaker to trip because you are drawing too much current

#3

no, it worked perfectly in practice. It was zooming around the room. So the robots weight isn’t the problem. Also we had a really simple autonomous, nothing stressful.

#4

  1. was the battery charged? :stuck_out_tongue:

  2. was it only the drive that was doing that?
    was the arm/claw/anything else working normally?

  3. what system are you using?
    crystal, old vexnet, cortex?

#5

The battery was fully charged. 98% of the time it was the drive motor. But every once in a while the lift would spaz out too. We are using VEXNet with easyc V4 cortex software

#6

Did you try changing your transmitter battery?

Was the robot IDENTICAL to how it worked in practice? Any additional weight at all? How long did you drive it in practice? Are all of the parts still bolted down tight?

It sounds a lot like you drew too much current driving and are tripping circuit breakers. Perhaps your practice field isn’t as grippy as the competition foam. The foam’s added grip may require your drivetrain to have more torque.

#7

we had a similar problem when we competed, which caused us to rank poorly, but anyways, our solution was to remove the back up battery, we then had no problems with our drive motors dieing.
we had driving our robot without connecting to any type of field controller while we practiced and it worked fine, but then at matched it would die very often.
but try removing the back up battery, this was a solution for us and one other team at the competition.

#8