Chassis problem


So I changed my 2 chassis motors to speed as in gear ratios, afterwards one side of the chassis died out in within 3 minutes. I’m not sure what is causing this. Here’s a list of what I’ve done: replace the motor, replace the gears, test the motors separately (they work fine), and the friction on both side of the chassis is the same. Why is the other side dying? Also before I changed both motors to speed and they were on torque none of them ever died out


Because your chassis only uses 2 motors, the higher ratio of the speed motors put to much stress on each motor. Adding 2 motors to you chassis will cause your chassis to not die out.

True, but right now we’re just looking for the cause of that one motor dying out.

What size wheels are you using? A smaller diameter will cause you to move more slowly, but will put less strain on the motors.

Two, speed motors are not enough to run on a drive alone. There is too much torque or friction in the system for two motors to move the robot for a sustained amount of time. How heavy is your robot? (estimate). I think you will either have to go back to torque motors or add two more motors. Have a nice day, hope you fix the problem.

It is probably because of more weight on one side, seeing that you already swapped motors, checked friction, ect.

If the robot is light enough, two motors is plenty to run a drive (ever seen a squarebot or clawbot?) but on most competition robots four motors is generally needed to reduce burnout issues. Here, changing the motors to speed reduced the torque enough to burn out the system. When we went from a 2:1 gear ratio to a 3:1 gear ratio we burned out after extensive driving for the same reasons. Two speed motors do not provide enough torque to power your drive, so either add more motors or gear it back down.

Thanks for all of your responses. I “fixed” the problem by adding some more motors like Cameron said with both being torque, now the robot’s chassis never dies out. However it is a little slower than we want it… does making on pair of motors speed and one pair torque change anything, or should I change all of the motors to speed? I think our robot is about 10 or 12 pounds, it’s not that heavy.

Assuming you mean each side has one speed and one torque, that’s even worse for the motors because as the speed motor will be more stressed, and as the drive gets to higher speeds the speed motor will have to pull the torque motor to speeds faster than its top speed. Every motor should be spinning at the same speed, if they’re not then you’re putting a lot of stress in the system, enough to shatter the internal gears of the motor. A four motor drive, speed or torque, should be enough to drive any 10-12 pound robot with ease.

If it’s only 10 to 12 pounds you could put turbos in there.

Whatever your gearing is, make them all the same. On a light robot (~10 lbs), you should run turbo. On ~15 lbs, you might be able to use turbo on 3.25" wheels. On anything heavier, but lighter than 25 lbs, use speed on 4" wheels.

Try to either make the motors back to torque, or add 2 more speed motors. The motors aren’t strong enough when at full speed to move a whole robot if it’s just 2 motors.

The OP has since added 2 torque motors (the original ones are still speed). See post #8 for more details.
I highly recommend changing the 2 new torque motors to speed. That will eliminate motor fighting. Right now, what is happening is the speed motors are trying to spin at 160 rpm, while the torque motors are trying to spin at 100 rpm. All 4 motors should be spinning at around the same speed, so they are right around 100 rpm or a little slower.