We’ve been having issues with our 2021 neos burning out ever since the 2024 spark max firmware. So far it’s burnt out 3 neos and the spark maxes were brand new when it happens. Has anyone else had this problem and if so do you know how to fix it?
So far we haven’t seen any other correlation to why the neos are breaking and these motors were fine during preseason.
What were you doing when the Neo’s were burned out? Do you have any current limits in place?
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We were testing our robot when it happened and they were acting completely fine for weeks then they randomly burnt out. 2022 neos were acting fine when we replaced them to that same spot.
We have 40 amp breakers on the PDP for current limits.
You’ll need to provide a better description - were they on the drive train, stalled on a climber, what? And how long were they running for? Breakers are not current limits - you can pull a lot more than 40A for short periods through a breaker. Current limits are typically set in the motor controller to prevent it from pulling too much current and prevent burning out the motor in an accidental stall condition.
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Two neos with 36:1 gearboxes are lifting an arm which is about 15ish pounds. They were working for testing for about 2 weeks ago using PWM. We only tested for ~1 minute, and it was able to lift the arm no problem. Then we switched them over to CAN. The next time we tested it was trying to tune PID, and it seemed like the motors didn’t have enough power to lift the arm. Both the motors and motor controllers were hot, and this same exact thing happened to use previously with 2021 NEOs.
The other neo that burnt out was on drivetrain and we have since switched out the neo and the spark max. It works fine now.
If they were hot to the touch, then it implies they were working quite hard - is it possible you had the two running in opposite directions, fighting each other?
They weren’t fighting each other and were going in the same direction.
Both the spark Max and neo were hot to the touch on all motors that broke
That heat comes from passing a large amount of current through them, which typically happens when you stall the motors or use them near stall for extended periods of time. From your description that you had two motors lifting an arm and “didn’t have enough power to lift the arm” before they burned out, really makes me think they were fighting each other. You said you were tuning your PID - is one set to follow the other with a single PID loop, or do you have two separate PID loops and independent control for each motor? If the second, it’s entirely possible that they were fighting each other without you knowing.
Also, did you verify the wiring before swapping the motors? White to white, black to black, red to red, and the encoder cables were plugged into the correct Spark Max’s? Improper wiring, or a bad encoder cable can lead to a whole host of problems…
There is one PID loop and one motor follows the other inverted. Because they are set up so that the motors are facing opposite ways.
And did you confirm the direction the motors spin, and that each motor was actually spinning, with them mechanically disconnected from each other? a 36:1 reduction is a huge reduction, and if one motor wasn’t spinning while the other was, that would introduce a lot of friction to stall/near stall the one that was, even if they weren’t fighting each other.
They did both have the correct status lights that they were going the right direction and moving.
My first step would be to disconnect whatever is coupling the two motors together and verifying that they’re actually both turning in the direction that you think. Don’t just look at the status lights – look at the actual motion they’re outputting.
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Jon is referring to current limiting the controllers themselves. The auto resetting breakers are not exactly the same type of limiter.
To protect your motors from currents that are too high, it is a best practice to limit your current both with the SPARK MAX’s Smart Current Limit and an appropriately rated circuit breaker.
Circuit breakers, while an extremely important part of a robot’s wiring and safety, are only designed to trip at a specific temperature, after a set amount of time, to protect the electrical system from fire or other electrical hazards. Due to this, we recommend setting a Smart Current Limit to protect your motors from damage due to high currents.
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Calling @Greg_Needel Is there a good reason why the spark max firmware doesn’t default to something “safe” like maybe a 40A current limit? Well informed teams would be free to adjust the limits upwards, but the less informed would kill many fewer components (would still cook 550s). I have seen way too many problems like this when it feels like there is a relatively simple solution, although I am admittedly ignorant regarding firmware limitations.
The only thing connecting the motors together are CAN wires. The only thing that has changed is that we switched from PWM to CAN, and it was working last Thursday with PWM. All of the other wiring hasn’t changed at all. The motors burnt out after we were starting to implement/test PID and switched to CAN.
This kinda happened with our other 2021 neo that was on our drivetrain. It worked for a while, but then it randomly burnt out, we checked everything to see if anything was wrong and nothing was. The other spark max and motor both also got really hot . We never tested or did anything with PID and CAN on the other neo.
We have the smart current limit set in the spark max and I’ll have to check later today what is set to.
Sorry it’s taking a long time to reply I’m trying to talk to my team and reply to this during school
Mechanically?
Disconnect both gearboxes from the arm. (Or motors from their respective gearboxes.) Then do the test that is asked for. If one or both doesn’t move the way it’s supposed to, then that’s your problem.
We are planning on doing that test today. Although I don’t know how well it will work because they might be fried now. But it doesn’t explain why we’ve only had 2021 neos break and they’ve only been breaking since the spark max 2024 firmware update. All of our neos have been fine and work great.
For electrical: About a month ago we had 3 newer neos and one 2021 neo on the drivetrain and the wiring was setup the the same way as it is for the other 2021 neos I’ve been talking about. The only thing different with the wiring setup is that they are connected with PWM instead of CAN. We didn’t have any issues with them except for the one 2021 neo we had on the drivetrain and the issue didn’t show up for a while. We replaced the 2021 drivetrain neo with a new neo and spark max and haven’t had any issues with the new neo or spark max. So I don’t think it’s an electrical issue.