Heat/Friction of 775 + Versaplanetary

[timytamy]

Lots of good info/thoughts.

We're pretty confident we've got the right amount of grease etc. We've used the versaplanetarys before without issue.

Originally Posted by R.C.

To confirm,
OP are you using the piloted versaplanetary plates or the metal plate?

We are indeed using the plastic (injection moulded?) plates from some of the more recent versaplanetarys.

Originally Posted by cbale2000

This might be a dumb question, but what is the ambient temperature of your workspace? Just noticing OPs location, and given the hemisphere and time of year... Just a thought.

Haha, good question! Outside we're seeing temperatures of ~40 C, but I don't think we'd ever see more than ~30 C inside. While an interesting factor, I don't think it can explain the massive power draw on idle.

From the sounds of it the most probable explanation is alignment issues. However since we've pulled this gearbox apart and put it together multiple times, I don't think it's a simple user error. We'll get the students to swap out the motor plate tomorrow and see how that goes.

[Paul Copioli]

Originally Posted by timytamy

Lots of good info/thoughts.


From the sounds of it the most probable explanation is alignment issues. However since we've pulled this gearbox apart and put it together multiple times, I don't think it's a simple user error. We'll get the students to swap out the motor plate tomorrow and see how that goes.

One common thing I have seen people do is get the input housing and output housing rotated 90 degrees from where they should.

The bolt patterns for the motor mounting and the VP assembly holes are not on the same diameter, but are close enough that they can be brute forced to "work".

The easy way to tell is to make sure the side bolt holes on the input and output slice are facing the same direction. If they are 90 degrees apart, then you will have problems.

Finally, if you think there is just something wrong with the alignment, then please contact our support. With the tolerances so tight on these gearboxes sometimes a few parts won't mate quite like intended.

As a side note, in the first year we actually sold pre-assembled single stage gearboxes and tested them for current draw. However, strong customer feedback was that the customer wanted to only buy the 1:1 (aka input and output + hardware) and buy the planetaries and ring gears separately. Once this happened, full testing was no longer possible and we needed to rely on our tolerances of the individual parts.

Any, I hope this helps you determine what is going on.

Paul

[mman1506]

We are having a similar issue with the 775 pro and VP. We are drawing 30w when the output stage is not in place (normal) and 180w draw when the 1/2 hex output stage (1:1) is in place. We've tried two different output stages both with a reasonable amount of lithium grease.

[squad1706]

We are also having a similar issue. We put together a 15:1 ratio versa-planetary, and after running it free on the table for about 3 seconds the planetary set was already quite a lot warmer, after an additional run of about 10 seconds to work some of the grease around (and yes, I have read the thread, there is a safe, but adequate amount of grease in them) they were approaching a temperature close to being too hot to hold. We are using all the proper VEX parts, and are put together identically to our others on our swerve system(obviously not the same ratio or motors). The ones on our robot however haven't ever gotten very hot, not until this 775 was hooked up to a set did they heat up.

[Drew_trak]

Does anybody know the proper lubricant to use on a Versaplanetary gearbox? brand? Link? We are planning on using a 775pro attached to a VP 28:1 ratio if that affects what to use.

Thanks!

[Richard Wallace]

Originally Posted by Drew_trak

Does anybody know the proper lubricant to use on a Versaplanetary gearbox? brand? Link? We are planning on using a 775pro attached to a VP 28:1 ratio if that affects what to use.

Thanks!

Page 12 of the user guide says "A liberal application of white lithium grease is required on all gears."