My base at the moment is running 4in high speed on 4 motors chained. our robot is roughly around 13 pounds and we have stumbled into some stalling issues. Our robot’s right side is the one that always burns out. The left side has never burned out in our practices and scrimmages. Because of this we are assuming that is the friction. What could be the source of this friction. Pls help with world coming up rapidly we would love to fix this issue immediately .


Check internal gears. If you’re running an encoder on that motor, there could be some issues. Try to cooldown your motors with air duster after practice and matches.

Also, what is your port allocation? Is the left side on a power expander? Are the left and right drive sides on two different cortex PTCs?

I dont have any encoders on my drive and the air duster does not seem to be helping a whole lot tbh

i have the left 2 motors on the 1-5 circuit and 2 right motors on 6-10 circuit. along with 4 motors on the power expander and 2 motors from my lift on each circuit

Are the four motors on the power expander from the drivetrain?

the 4 motors are from the lift

is it possible that the circuit that the right drive train is on is faulty by any chance?

Check your code and using a 9volt battery to make sure all motors work and are running.
Check for exposed copper along the wires (shorts the motor if exposed).
Try switching one left motor to a port that is currently used by one right motor.
Disconnect all wheels from all motors and spin the wheels. If it doesnt coast for a few seconds, then there is friction. Make sure the bearings are still sitting properly in their holes and the chain has a tiny bit of slack.

@Duke4221c This sounds like a cortex PTC problem to me. This test will confirm if it is or is not:

Does the lift slow down significantly/lose strength when the left drivebase goes out?

  • You said that half the lift is on 1-5 and half on 6-10, but its through the expander. If the cortex PTC is bad, it would trip the whole thing, thus turning off half your lift as well.

Other than that, follow @Bryan R 's suggestions. It very well could be a short.

The picture isn’t showing up for me, can you turn link sharing on? (Will make it accessible to everyone)

ill try what you suggested. however, although i supect friction, when i take the shaft out of the motor and spin it, it will coast for long periods of time. longer than a few seconds. atleast 5 seconds

it is the right side of the base and my motor configuration are like this
1: right drive
2: right drive
3: y cable into the powerexpander
4: lift motor
5: Nothing
6: nothing
7: Lift motor
8: y cable into powerexpander
9: Left drive
10: left drive

i have the y cable going from my cortex into the power expander that is powering 4 out of the 6 lift motors. essentially 3 and 8 is y cabled controlling 4 lift motors and the other 2 is controlled separately on ports 4 and 7

@Duke4221c Ok, definitely not Cortex PTC. Your port mapping is perfectly mirrored and distributed.

  • Turn each wheel by hand - is there a difference?
  • Check the entire length of the wires for every motor on base
  • Take off green motor caps and check wire where it connects - it is frayed/ shorted?

Write a section of code that uses the 8U, 8R, 8D, and 8L to run each of the motors individually. I have heard of ports 1 and 10 no longer working after some use.
Finally, make sure all internal gearings are the same.

internal gearings are all the same and i have made sure all motors work

-Some motors may be too old. Try buying new motors and replacing them.
-Check code to make sure there are any discrepancies that would make a motor turn in an undesired way.
-Try changing to 3.25 inch wheels.
-Try using a six motor drive. A four motor lift is enough even with 1:5 gear ratio. You can even use high speed gearing if you use elastic correctly. Or if you decide to use four motors on the lift you could use high strength gearing.
-Try adding slew rate. This allows you to control the acceleration of motors. A higher slew rate value would cause the motor to accelerate slower so that it won’t put too much stress on the motor.
-Try driving more composed. If you find yourself constantly adjusting and turning the joystick, it means you aren’t very practiced. This spastic driving would put your motors under so much torque due to constantly switching the current to spin the axle ccw, cw, then back to ccw.
-Be careful of your field. There may be a lot of static that would cause a discharge and briefly disable your robot. You can solve is by discharging the robot by yourself before driving (although I must admit that I myself don’t know an effective way to do that and am open to suggestions).
-Check to make sure that your robot isn’t stuck in a while loop.
-If you are using an LCD display (I doubt this is the problem) try driving without it connected.

That’s what I can think of as of right now.