Hi everyone, this past Saturday we were driving our robot and our arm gearbox made a very loud groaning sound it turns out the the NEO controlling the bottom joint of our arm had seized. luckily there was not a ton of damage but we were unfortunately not able to continue driving the robot. we took the robot back to our shop so that we could put our spare arm on so we could keep testing. we puled apart the other gearbox so that we could do some more investigation and we discovered that the actual gearbox was luckily fine but the NEO was completely seized. We took apart the NEO further to keep investigating and when we removed the outer shell we were able to turn the motor with a considerable amount of force. It was also making a clicking sound that was definitely not normal. after removing the core of the motor we discovered that three of the magnets had come out of position. We think that this was a quality control issue because we have not had this issue with any other NEOs even though we have run them much harder than this case. We are planning to contact REV to see if we can get it replaced. Has anyone else had a similar issue?
All ours have been working great (we fried 1 or 2, but that was 100% user error).
Would definitely encourage you to contact REV (as you mentioned you plan to do) to see if they can help diagnose the root cause of the issue.
I have never heard of this issue but I am sure if you report it REV will do a good job at QA to check for it and do right by you!
This is a potential issue with nearly every brushless motor, because the outer magnets are usually glued to the shell and a hard impact (like your robot slamming down on the floor) can break them loose. We’ve seen this failure in both falcons and neos (though never 550s), and I’ve just chalked it up to the stresses we put them through.
Difference being, when this happens to a motor without a motor controller built in, it’s much less of a cost issue.
After using neos for a few years my team has learned that they dont like to be stalled to hold the position of an arm or elevator. Do the same thing with a cim motor and have absolute no issues.
Update: we had the same issue with a different issue. this time we were smart and brought our spare arm so we were fine but we are running out of neos and are nervous this will happen during competition. we are going to email REV and ask for new ones but they sadly wont get there in time. fortunately we have asked around to other teams and they have some that we can borrow so we should be fine for north star.
My team has had this issue with one neo v1.1, one magnet’s glue gave out, causing the same clicking and occasional binding. Upon inspection of the inside of the motor housing, it looked like it had gotten hot enough to melt the black paint (assuming the inside is painted.) as one part of the paint was gone and down to bare metal. I did not see any scorch marks or soot, however, so it may just be that the inside isn’t thoroughly painted.
Do you have a picture of your setup? Arm gearboxes can be high-load and there could be an issue with your gearbox/application that makes a motor failure more likely. Pictures would help provide guidance.
yea ours looked the same but it was on the back of the shell not the side where it would have been the most hot so my guess is that the paint was not the best quality.
i can see why this is a possible issue but we havent had any insane impacts this season so I don’t think this would be the issue. im curious how it happened to your falcons because we have had the same 8 since 2020 and not had a single issue with any of them even after taking them through more than 5 comps.
thanks to our arm being on such a big ratio it can actually hold its weight without break mode. but last year we did discover that neos like to smoke if you stall them for longer than 2 seconds.
this is a picture of the robot at Northern Lights. the motors are at the bottom of the gearbox and the one for the bottom joint is on a 600:1 ratio while the top joint is a 300:1. in our testing the only time they have gotten warm is when they have already failed and there is a crap ton of resistance. we don’t think that that load is unacceptable because we made absolutely sure the math was right this year because we know what happens when you get the math wrong.
If you stall them above their current limit, sure. But I think you learned the wrong lesson, I’ve stalled NEOs tons of times with no issues because they were stalled below the rated maximum current limit.
You can stall a NEO for the entire duration of an FRC match with no damage to the motor if you gear correctly.
I would encourage you to check out REVs published locked rotator testing for more information.
Edit: changed stall torque to current limit.
We’ve had this recurring issue as well, with the motors placed on our intake arm.
Just like @Tom_Line said, the nature of our intake made it so that the mechanism experiences a lot of repetitive shock when we actuated our wrist down in order to intake tipped floor cones (as well as when we use it to push the charge station over to help with docking). Upon taking the neos apart, there were multiple dislodged magnets (unsure how many I forgot). This failure occurred on multiple Neo 1.1’s after swapping the broken one out for a new motor. We swapped to original Neo V1’s we had on hand, and didn’t see any more issues with magnets dislodging (this can be purely anecdotal considering we reduced our wrist actuation speed to try to reduce shock loads as well).
It looks like your motors aren’t being used in environments which would easily break the magnets loose. Are your motors experiencing any larger than normal vibrations over extended periods of operation? Could you share a closeup of how your Neos are mounted to the gearbox?
So last night we rebuilt our arm again because of our issues. we decided to open up the last v1.1 neo we had and the BRAND NEW motor had magnets we could move around with just our hands. we did the same with a dead motor from last year (so a v1) and we were able to remove the magnet but not without a screwdriver as a chisel. attached is an CAD image of how the motors are mounted to the gearbox. the CIM sport gearboxes are a 100:1 and a 48:1.
these are the best pictures I can get but let me know if you have any questions about it
There’s a lot of gaslighting-adjacent behavior going on in this thread.
OPs robot and gear ratios seem incredibly reasonable. They have reported that even brand new NEO 1.1 have this issue. Other users have chimed in to say they have the same issue.
It is painfully clear to me that NEO 1.1 has a serious QC issues at this point. @Greg_Needel may need to debug this soon to know how many motors are affected and prevent more faulty ones from making their way to teams.
EDIT: it’s actually almost funny how good OPs design is here. Throwing the motor directly into a COTS planetary it such a good way to protect the motor, and the gear ratios themselves are very high. The arm is driven in a way that minimizes backlash too. Just a really good design.
