CIM Motor Trouble

A few days ago we were testing our climber when the code got changed and we ran our motor against our ratcheting wrench. This caused the motor (or possibly something else) to start making a clicking noise when weight was applied and then made the motor stop functioning correctly. We had the motor hooked up to a two stage, 50:1 versaplanetary gear set driving a drum; but after inspecting, replacing, and trying different gears, it still refuses to work and continues to make a clicking noise. We’re stumped as to what could be the problem and are thinking of changing the design within these last few days.

Did you try replacing the ratchet and/or the motor?

Take a close look at the sun gear of the 10:1 stage of your gearbox, it’s a very sneaky failure if the weld at the back of it broke and it is spinning relative to the spline. If you have a TIG welder you can simply re-weld this and be good to go.
The 9:1 stages are updated to a D-D press fit between the spline and the sun, which mitigates this failure if you’re okay with a 45:1 ratio.

Just my hunch as to what your issue may be.


Quite the coincidence that yesterday, we also tested CIM motor going through a 50:1 versaplanetary gearbox as our winch. To test the climber again, I’d recommend running the motor without a gearbox just straight off of a battery to see if there are any problems there, then with the gearbox (was the gearbox properly greased?), and finally, on the robot without the wrench. Yes, during competition it will be on there, but for now, nail down and troubleshoot each part of that assembly until the problem is solved.

I have seen CIMS stalled for minutes with no adverse affects. I don’t think this is your problem. Try running it unloaded and off the gear box. I bet it still runs fine.
Sounds like something in your gear train

Does the motor still make a clicking noise and not spin when removed from the gearbox? If so, the motor’s obviously shot, get rid of it.

If not, try each stage of your gearbox one at a time, does the issue return? If it does with one of the stages, look there. Note Aren’s post about the 10:1 issue.

If it works with both stages individually, but not together, be sure everything in your gearbox is properly aligned and coupled.

Finally, make sure the wrench allows free rotation in the proper direction, it’s an easy mistake to make.

Is there a chance the clicking noise was actually the 40 amp breaker?

We had a similar issue with Mini CIMs in Veraplanetary Gearboxes last year. We had them hooked up to a 2-Stage 100:1 Ratio and found that this is wayyyyy too much for the gearboxes to handle and actually shattered the planet carrier inside the gearbox as well as shearing all the teeth off of one of the sun gears. My guess is you have too much torque going through it and has caused some failure inside the gearbox itself.

Take it apart and look inside and see what’s broken. Also, before you continue with this design, check this out from VexPro’s Versaplanetary page:

It’s a load rating guide for what motors you can use safely with different reductions. Assuming you used a 1/2 inch output shaft, it looks like that 50:1 2-stage using a CIM for power is too much for the gearbox to handle safely.

It is in the red zone if the second stage is the 10:1, but in the green zone if the second stage is the 5:1.

In general, it is best practice with these gearboxes to place the highest reduction stages closest to the input, as it will put them under less load. So if the gearbox is 5:1 followed by 10:1 right now, and the 10:1 is stripped, you can put the replacement 10:1 in as the first stage to get a bit more strength (or better yet, go to the 9:1).