NEO Brushless post testing opinion?

#1

So, it’s been some time since the NEOs came out.
Was wondering if anyone has been using them for long enough and can tell about how battle proof they are? Any errors? How reliable would you say they are?

Really considering using them this year for our Drive, but a bit scared of working with untested (by me) motors on there.

Thanks

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#2

I would personally net switch this late in the season. there are some teams that have done it, but have closely worked with rev to iron out a lot of issues that have come out throughout the process, that is the reason why you have seen so many updates from rev over the last couple of weeks. I would wait till next season if you haven’t been developing this entire time, by that point any other issues should be fixed

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#3

We are using the NEO’s on our robot based on the testing and the continuous firmware upgrades we determined we would give it a shot and so far they are great if anything fails we can do a quick swap with cims and 1 line of code

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#4

Our programming and electrical students were excited when they got them, and we decided to take the risk. Satisfied with them with the only problem being a bad sensor cable on our part. However, your mileage WILL vary and, if feasible, I recommend testing them before deciding.

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#5

I can’t say as we’ve really put their durability to the test per say, but that acceleration rate when used on a drive system is no joke, these things get up to speed FAST.

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#6

We have put these motors to the test, and on multiple different subsystems as well as drive, and would not replace them with anything else at this point. We are very happy with the results.

If you have any issues with them let us know we can help if needed, but I do not think you will have issues with them. The acceleration and power and weight reduction is incredible and worth it. :slight_smile:

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#7

We currently have 8 on our differential swerve and one for our elevator. We are very happy with what we are seeing out of these motors. Can’t wait to try them on the real field!

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#8

We had the exact same thought process. The 0.938 pounds compared to the 775pro (0.8) and around 380W output compared to the CIM (337W) is amazing.

Now just have to sit back and hope for a legal brushless 550/775/BAG style motor…

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#9

I think they are awesome for drivetrain purposes but we had one on our elevator and we stalled the motor to hold a position and it killed the motor and it wasnt stalled very long.

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#10

How long?

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#11

Around 30 seconds

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#12

@sticky_1629

30 seconds at a full 12V stall would probably kill most FRC motors except for a CIM. Note that you’re effectively forcing the NEO to dissipate 150A * 12V = 1800 W of heat for 30 seconds. Compare that to your average 1500 W space heater. My math may be a bit off as I’m not really sure how this sort of thing translates to brushless motors, but hopefully that gives you a ballpark estimate of the amount of heat that the motor has to eat.

I realize that this instance was probably a one-off thing, but I’d urge you to reconsider your gearing if your mechanism requires you to stall your motors at anywhere near full voltage. Consider constant force springs to counterbalance the elevator weight or increasing the gear ratio. CF springs changed our dual-NEO elevator from one that would struggle to move at 12V to one that reaches full extension in <1s.

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#13

Do you know what the voltage, or at least percent output, roughly was during those 30 seconds?

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#14

It was only being stalled at 12-13% power

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#15

And it does fine with cims

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#16

We are using 6 NEO’s on 2 VEX Pro 3 CIM Ballshifters.

The only problem we have run into was browning out. Running all 6 of the motors at 100%, then immediately swapping to -100% would cause the robot to rapidly brown out without fail.

We fixed this by putting the motors in coast mode and applying a current limit.

I would assume the same would happen with a 6 CIM / 8 775 drive, but do not have the evidence to back that.

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#17

Think that is pretty common with other super-powerful drivetrains too. The motors take a lot of current when accelerating from rest and that would be exacerbated by having 6 of them. Even more so if there isn’t any current limiting.

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#18

what ratio did you go with? just wondering

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#19

It would be worse on a 6 CIM drive, most likely, because the CIMs draw more current and are less efficient.

On another topic, has anyone done a locked rotor stall test with NEOs, or have plans to do one?

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#20

So where would one look to find out a safe stall time for various current limits on the NEO? Vex has that kind of data for the 775s, which is why we’re comfortable stalling four of them at a 15A (input) current limit for a few seconds, and at 9A for pretty much the whole match. But if we switch the elevator to 2 NEOs, they’d need to stall at 30A each. I have no idea how long it would take to heat up a NEO to insulation-melting temperature at that current.

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