Motors Randomly Stop running

The motors for the claw and arm on our clawbot will randomly stop running. You can still hear the motor trying to run, but it doesn’t have enough strength to lift the arm. The arm is made of aluminum. We’ve already changed the motors once. The motors do get quite warm when this happens, but we don’t get an error message on the robot brain. Here some pictures of our robot. Any ideas what could be going on?

It sounds like your motors are overheating and self-limiting their power in order not to damage themselves. You can avoid this by reducing the strain on the motors, which can be achieved in two main ways:

  1. Reduce the force needed by the motor to move whatever it is connected to. This could mean larger gear ratios to give the motor more leverage, or it could mean adding passive support such as rubber bands to a lift to counteract the force of gravity or the weight of a game object
  2. Ensure that you are not stalling the motor needlessly. A common way this happens is when the motor is being told to spin something like a claw closed when the claw is already closed, but the motor continues trying its hardest to close the claw more, causing it to stall and heat up. In such a scenario you might want to either use voltage control with a low voltage so as to limit the power used (and dissipated) by the motor, or by shutting the motor off entirely.

Looking at the picture, it doesn’t look like you are using bearings on arm joints. This can cause excess friction, thus increasing the load on the motor. Try adding bearings to the arm joints, everything else I can think of has already been said previously.


What types of bearings are you talking about? I checked the vex robotics website and there’s a good variety. If you could give me the link to the vex website to buy said bearings, that would be great. Thank your for your comment.

Here’s another picture of the robot

It does look like something may not be quite aligned properly. This is what a standard V5 clawbot usually looks like.


in this case, you would probably want to use either a bearing flat:

or a hex nut retainer with a bearing flat:


If your VEX parts came in a kit, that kit almost certainly has one or both of the bearings pictured above.