So we are on our third lift of the season so far. It is a DR4B. It is a two motor high-speed 1:7 lift. On this lift however, the lift seems more prone to stalling. We took out the motor axles and properly tensioned rubber bands and checked for friction. We replaced the motors, which didn’t fix the issue. We know the issue is not weight as our old lift was heavier and had no problem with burning out. Could this be a problem with the motor controller or brain?
thank you.
It may be a motor controller, they do tend to break at the worst times, but it sounds to me like there’s just too much strain on the motors. It looks like you checked everything I would have recommended, (weight, friction, and bands). I think the best way to narrow down the problem would be to replace the motors with torque gearing. If it still burns out, there’s probably something wrong with your code or motor controllers (again, assuming friction and stuff is all fine). If it works fine, then either try to reduce weight and get rid of more friction, or just leave it on torque (we found our lift is faster overall with torque gearing due to the increased acceleration speed).
One of my school’s teams was having trouble finalizing their robot for states because their lift dr4-6b was having trouble lifting on a 1:7 hi-speed ratio, and even sometimes on a 1:7 torque ratio. I recommended trying out half c channel on the top 6 bar part of their lift. They only ended up changing the top two bars on each side (out of a total of eight bars), and after that their lift ran on 1:7 hi-speed faster than my team’s dr4b, which didn’t use any half c channel at all.
tl;dr → half c channel works miracles
we had a dr4-6b before which was heavier than this lift, and never had a problem on the same ratio.
I suggest a friction test with the motor axles in place, motors split open (only the motor face staying on the robot) and the last motor gears coupled to the axles. A pretty common issue is a slight mis-alignment between the axle and the hole in the motor face, causing significant friction when the motor is installed.
Did you Check the axels of your actual larger gears, they tend to bend more easily
2 Cases if you did alignment and spacing properly:
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The lift is currently straining really hard and not very fast, meaning that it’s either friction (make sure that your screws can move easily when you turn them with a screwdriver, otherwise they’re too tight), or bending of either axles or c-channels.
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It’s fast, but still burning out when it goes up and down, which means that it’s resisting its own motion and attempting to jump straight from 100% power to -100% power. In this case, just try coding a slew.
Or your wires are just bad.
Thanks everyone, it ended up being the motor controller. We switched it out and have been able to run for 20 minutes straight with no issue.
