NEO Motors Running Extremely Hot

Hey all, my team, 747, has got some serious problems with our NEO motors and we were wondering if you all could help. After 40 minutes of driver practice, all four of our drivetrain motors began to get extremely hot and have a very distinct burning smell that sort of smells like paint. Have any teams had any experience like this and are there any possible solutions/preventatives?

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The NEOs are new, so we’ll be learning a lot about them. The match only lasts 2.5 minutes, so you are definitely testing the worst case with 40 minutes of driver practice.

How do you have the motors mounted? The motors will run cooler if they can pass the heat into a metal frame (i.e. the heatsink can sink the heat from the motor). The 775s or earlier version ended up with heatsinks that wrap around them. This may be something the NEOs need too.

We are using NEOs too, so I’ll post our results when we get something interesting.

Gear ratio and robot weight are also necessary to determine if there’s a problem.

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Was it 40 min straight? A CIM motor might be untouchable after that.

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MAKE SURE your Spark MAX motor controllers are set to Brushless the lights should be Light Blue (Cyan) or Purple (Magenta) if not press and hold the small button on the controller to change the mode. Or if using CAN make sure you are initializing the controller as Brushless.

This page has a description of all the status lights:
http://www.revrobotics.com/sparkmax-quickstart#status-led

(I am Impressed that you are already doing driver practice, bravo!)

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Haha, thanks, but all of our driver practice is being done on last years robot since we moved to a new joystick system and we are trying to get accustomed! They are definitely set to brushless mode, I programmed them to auto update to brushless at the start of every major subsystem and command just in case. After they cooled down, one of our four motors is completely fried. It makes noise and shakes and goes slow or doesn’t go at all. I advise EVERYONE to take extreme caution regarding the temperatures of your NEOs!

I work with brushless motors on a daily basis. Can you clarify a few questions, just to rule out any installation or usage issues?

  1. How long are the wire runs from your motor controller to the NEO?
  2. Are all the NEO’s driving the correct direction? (you can flip a motor by swapping a phase wire)
  3. Is there sufficient airflow around the outrunner shield, or is the motor not subject to true ambient temperature?

Assuming all of the above are reasonable, it sounds like we might be learning the duty cycle of these things when driven hard.

Does the other side run as expected once the temperatures come back down? I’d certainly expect a drivetrain to run poorly when it’s carrying the dead weight of a fried motor, no matter what motor that might be.

The other side works perfectly and when we pulled the breaker on the broken motor that side ran as expected

The wires are a little less than a foot long. I am certain they are running in the same direction because everywhere in our code we set them as followers, and it was working fine right before the temperature went up. I am fairly certain there was sufficient airflow, but I cannot confirm

Any chance you could share a photo of the NEOs in your setup? I remember reading somewhere that the NEO’s should be mounted to aluminum to act as a heatsink.

That is exclusively based on the time you ran them for. I would never run a CIM that long either. Don’t worry about it, but also for the future I tend to take a break every 5 or so minutes. No sense in burning up a robot to save a few minutes.

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Also, my team bought a bunch of neos and we plan to use them instead of the CIM. If i notice something i’ll let you know.

@techplex This is the left-side transmission of our drive train. The motor that failed was on the right-side transmission, which we disassembled last night to replace with a different motor and verify the transmission was not at fault.

Part of the issue is that by mounting the NEOs to the glass-filled nylon gearbox as opposed to a metal plate, there is less heat dissipation than if it were mounted to a regular gearbox.

The other part of the issue is that you ran the motors for 40 consecutive minute of drive practice.

If you want to keep the gearbox as is, you could add heat sinks to the outside of the motors and a cooling fan for airflow to try and get more life out of them. Additionally, I would recommend not practicing for such continuous lengths of time - when you have to change a battery out, give the robot a couple of minutes. This is a good time to go over any driver practice video, set up a new training drill, or review the robot code.

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Normally CIM heatsinks aren’t very effective because most of the heat generated in a CIM-style motor exits through the shaft, not the casing. I wonder since the NEO is designed to dissipate heat through it’s aluminum case if using a heatsink like this would help keep them cool.

I still think the answer is simply that none of the motors we use in FRC can handle that kind of extended load. Matches are 2:30, and you should never have to play more than 4 matches back-to-back (with 6 minute breaks in between). 40 minutes is much longer than any FRC robot would reasonably see. A good rule of thumb is whenever you switch batteries during practice, give the robot a few minutes to let the motors cool off. Otherwise even if you don’t damage the motors you’ll be practicing with less-efficient motors and overly-sensitive breakers so the robot won’t respond the same way as during a normal match.

Edit: completely sniped by @Chris_is_me

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Just to share our experience …

We ran our tank-drive chassis with 3 Neo’s per side for 30-60 minutes and the motors weren’t even warm. We were really surprised. So they can run cool. We did have them mounted to an aluminum gear box case. They were controlled via CAN and were on break mode. These things coast way more than mini-CIMs.

Note: We were switching drivers constantly so that may have given some cooling time.

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It seems to me that a lot of drivetrain-worthy gearboxes, like those that come in the Kitbot, have non-metal mounting for the motors…

Team 5431 has been stress testing the SPARKMAX and NEO’s on one of our test bases. We’ve run approximately 30 simulated matches, with 10 minutes between them.

We didn’t record any issues with heat being excessive from these motors.
We did record that the SPARKMAX seems to be a little hotter than a TalonSRX, but NOT excessively so.

They jury is still out if we will use them or not these season, but our results have been promising.

Don’t the SPARKMAX or NEOs have a built-in over-temp protection? Shouldn’t that have been tripped before OP’s motor fried?

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