Motors not working right.

My team is building a launcher with four motors working in pairs. We have an issue with the motors not staying in sync. We start them up and they run for a while then start to stutter. Does anyone have any experience with motors acting strange, and how to fix it? Could our configuration be the issue? We are also using chain, could that put too much strain on the motors? Any and all input would be greatly appreciated Dropbox - motors.jpg - Simplify your life

If by stuttering do you mean that they slow and stop running after some time? If so, it’s due to too much strain on the motor PTCs causing them to trip. What is your overall gear ratio and internal gearing of the motors? The most likely cause it due to excess friction, so be sure to check everything over. Take the axles a little bit out of the motors and see if it spins freely by hand. I have a feeling that your chain might be causing a ton of friction, in addition to the other normal offenders like misaligned bearings or bent shafts, etc.

I am wondering if the motors are overheating in that configuration.

Currently I am experiencing that same problem with my right side of my flywheel

Btw any way to prevent this is robotc. would lowering the voltage inputed increase the torque and let it run pretty smoothly?

no, lower voltage means lower torque and speed.
Generally as long as you don’t fry it, more voltage is a good thing

We have 6 motors in a block configuration like this for our drive, and overheating is not an issue. So I don’t think it is the configuration. They must have too much friction elsewhere or simply not enough power for what they are trying to do.

Your chain might be creating too much friction, especially at higher speeds. One problem with a loop of chain is that its tension adds up to a total unbalanced force that gets exerted onto the sprocket’s shaft, and this can cause a lot more friction between the shaft and the bearing than perhaps you would normally see. In the image below, the tensions T1 and T2 add up to a force that is not balanced and is acting on only one side of the shaft.

http://zigherzog.net/em211/p08a/belt_2.gif

Another possible culprit in stuttering could be your control system if it has some kind of speed control loop that’s not tuned properly, etc.