we have been having issues getting our 4 motor elevator climber to work. we are using a thriftybot style design with two elevator stages each NEO motor is on a two motor through bore 3:1 gearbox connected by a central axle, so all four motors a mechanically linked. we believe that this mechanism should have no problem lifting the bot from the second stage. JVN design calc says we should have nearly 170 lbs of output on the second stage. the elevator is extending just fine but when we tried climbing, it makes horrible noises and stalls the elevator. We thought it could have been a problem with our programmed smart current limits, so we removed the limit, assuming the breaker would trip if anything went wrong, however when we tried climbing again after removing the limit, the elevator stalled for a second, and then 1 of the four motors started smoking. We have tried removing the follow commands. When we felt all the motors, only the one motor that was smoking was hot, the other three motors were not even warm to the touch, so this leads us to believe that the other motors were either not doing anything or maybe that motor was turning in the wrong direction?. We have yet to plot the SPARK Max’s output in REV hardware client, but will do that later today and post back here with the results. Any point in the right direction would really be appreciated.
Can you post a screenshot of your calc? Normally desired load is an input of that calculator, not an output. What does it say your amperage is per motor?
The breaker is there to protect your wires from melting, the current limit is there to protect the motor.
A picture and some code would help, but it sounds like you might have one or motors reversed. You might like to try running with only one motor (with the others in coast mode) and then add the others one by one.
You likely have some of the motors going in different directions which is putting a ton of load on the motors with them fighting each other. Check how you put the motors on and see which ones should be reversed. It is most definitely a code issue though.
You’re using the thriftybot elevator with the black blocks that ride up and down inside the square tube? Recognize that any sideways pressure is going to create a bunch of friction that you have to surmount, in addition to lifting the robot. You can offset that a little bit by tying your string to the bottom of the top stage instead of to the top, but you might consider either a lot of lubrication (graphite has worked for us) or replacing the block with something that rolls. You might also go to a 4:1