Neo 550 Smoke Problem

we ran the motor for 5 seconds it started sparking and the smoking. when it cooled down we ran it again and it did the same thing. we switched out the Neos and it continued with the problem. the first time we ran it. it cooked the speed controller with the motor making it unusable.
any thoughts.

What current limit do you have the SparkMax set to?
Take a look at the bottom graph on this page: REV NEO 550 - Other Motors - VEX Robotics

What application is it being used in? What gear ratio are you running? Can you give us any more info? Pictures of the mechanism?

Edit: Sparking from a brushless motor is unusual, are the screws holding it on too long?

Maybe check the wiring

Looking into a current limit problem will update with more

It looks like it was just a current limit issue but I’m not 100% yet

It’s never just the current limit though.

The current limit is just a safety net to prevent damage. You could have a motor last forever with an infinite current limit as long as you never put it in a situation where it draws too much current.

The important question is why was it drawing so much current for so long? That means it was either completely stalled or at least operating on the rising side of the power curve.


I’m not certain that is the case with the Neo 550s. We have had them in simple spin a wheel mechanism. With no real load other than inertia and not that much. With no current limit if you run them full go they will let their magic smoke go.


I wrote up some notes on setting current limits, but it does sound like there is more to this story. What current does the PDB/PDH (or DS logs) report? What is the load on the motors? Can you move the load easily by hand when the robot is off?

We have learned the hard way multiple times that you have to be very careful with the mounting bolts for NEO 550’s. If even a bit too long, they will at minimum short the motor to the frame.

The mounting bolts that come with them are made for a 1/8” mounting surface. If you use it on something thinner, I guarantee a problem.

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