Gear Problems

Hi Everyone,

So my team and I have been having some problems with our gears. The shafts have been turning and it really shuts down on us (when it can actually keep going for more than 2 seconds). The RPM speed is also still not fast enough despite the motors on turbo. Could someone please take a look and give any ideas?

https://drive.google.com/folderview?id=0BwDwdSH6jnufMDktdFJEdGstUmM&usp=sharing

I’m not sure what you mean by “it really shuts down on us (when it can actually keep going for more than 2 seconds).” If it’s shutting down on you, then how do you know that it can go longer?

You’re most likely tripping the PTCs because you have too much friction. Check to make sure things are aligned properly, no bent shafts, etc. There have been many other threads on this forum recently that you should check out where people have been having similar problems where they are also most likely tripping the PTCs.

Also, switching to turbo motors probably made the problem worse, because turbo motors are not able to output as much torque, so they would be easier to stall.

What’s the gear ratio you have, it’s a bit hard to tell from the photos. You’re most likely trying to go too fast and the motors can’t give enough power, especially on turbo gearing. Most teams have no more than a 1:25 - 1:30 overall gear ratio with standard speed (100rpm) motors.

After studying the pictures for a few minutes, it looks like only one flywheel is set up to run, and it’s a total gear ratio of 1:49, with a lot of gears in between that aren’t really necessary. Including the internal gear ratio for the turbo motors, that is a ratio of 1:117.6, which is extremely high. This would require far too much torque to turn with just two motors. I would recommend lowering that ratio quite a bit.

As Kevin said, 1:25 overall works well. To give you a couple of possible configurations, you could do 1:7 (84t gear driving a 12t) with turbo motors, or you could do a compound gear ratio of 1:21 with standard motors (84t driving a 12t on the same shaft as another 36t, which then drives another 12t on the same shaft as the flywheel). There are other ratios that people have also found well that you can find on other threads.

Thanks Kevin and Bpalms. I’ll pass this on to my teammates.