NEOs cooling

#1

Now that teams have had more time and experience with neos, have any teams using neos struggles with the front face cooling nature of neos? I was thinking in applications like WCP gearboxes designed for CIMs and miniCIMs in addition to planetary gearboxes like versaplanetaries and AndyMark sports.

#2

The front face cooling is a fantastic improvement over the CIMs. One of the reasons we went with custom ballshifters this year (instead of Vex’s injection moulded design) was for the metal gearbox plates: they act as a giant heatsink. We almost never need to stop practice sessions to let motors cool, and the increased efficiency over brushed motors leads to longer run times.

We’ve also considered using thermal paste and adding fins to our plates, but they seem to be fine as-in.

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#3

We kept the mounting surface on the gearbox solid instead of pocketed, and haven’t had any issues with overheating gearboxes. If we did start seeing it, my first option would be to put some thermal paste on the front face.

#4

We love the front faced cooling, our bot had 11 NEOs attached to the base plates/gear boxes with a bit of thermal paste between them, after a bit of pushing the bot hard the motors would be cool and the base plates would be warm to the touch.

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#5

Do the EVO gearboxes have enough surface area contacting the motor to cool a NEO?

#6

We are using the EVO-Slims with 3 NEOs per side.
Our practice bot takes a pause when the compressor gets too hot, but never due to the NEOs.

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#7

We’re running swerve with Neos on the drive motors. They are actually mounted onto plastic spacers so not much front face cooling per se. However, the drive motors have never gotten more than mildly warm. We also have 7 other Neos in our bot, mostly on versaplanetary gearboxes with the cim adapter and they stay pretty cool as well.

#8

Did you have any problems experiencing melting plastics due to the contact of plastic with the front of the motor?

#9

Nope, none at all. They get mildly warm but not nearly hot enough to melt the plastic. They get warm in elims but not hot.

#10

Im not OP, but we smoked a NEO by stalling it at 12v for like 2 minutes. They’ve otherwise been stable.

#11

I sense a general disconnect in this topic; I’m going to try to clarify.

775 and 550 motors are air cooled, and have low heat capacity (thermal mass). As long as you run them well on the fast side of the power curve, you will have little issue. As soon as you get on the slow side for more than a few seconds, you are courting disaster.

CIM, mini-CIM, and BAG motors have metal cases, but are ultimately sealed brushed motors. As such, the bulk of the heat generated in them is generated on the ROTOR, and transmission of that heat to the external case is limited to radiation and transmission through the bushings/bearings at either end of the motor. These motors have high heat capacity (thermal mass), but rather slow transmission of that heat from where it is generated to the external case and thence to the atmosphere. They’re great at taking it up to a certain point, but beyond that, they need a lot of time or some creative means of cooling (ventilated connectors and dry ice being not as unusual as you’d think).

NEOs have plastic external cases, except at are designed to cool through the mounting face. However, as they are brushless motors, the heat is mostly generated on the STATOR (stationary, external case) side of the motor, which means that it is in direct thermal contact with the motor face. Further, NEOs are (if operated properly), significantly more efficient than brushed FRC motors, which means that less heat is generated in the first place, so the heat sink needs are reduced.

Bottom line: unless there is some unforeseen issue, NEOs should run significantly cooler than CIMs or miniCIMs in any gearbox with a metal motor plate, even if it is heavily pocketed.

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#12

The external NEO cases are aluminum.

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#13

Is dry ice allowed as a coolant for motors? Sounds like an interesting idea, but IDK if FIRST would like that.
Other possibilities:
Liquid Nitrogen
Liquid Oxygen
Ice
Liquid Hydrogen/Helium/Neon/Argon
Metallic hydrogen (Although the equipment for keeping that from turning into regular hydrogen is probably illegal under FRC standards)

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#14

Dry ice might be considered hazardous since you need gloves to touch it… Maybe a team could figure out how to get a water cooling loop going if it won’t count as a hydraulic system. (are fans considered a hydraulic device???)

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#15

We are using 11 Neos on our bot and although our drive motors will get warm to the touch after hard defense, cooling has never been an issue. We are using evo slims for our drive gearboxes. Our arm and climber Neos barely heat up at all. We have had Neos smoke before, but that was because we had them stalled on our bumpers for a good minute or so, and once we noticed and stopped them they worked fine after.

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#16

How fast is “well” ?

If you run them at full throttle at 60% of free speed how long before they sustain heat damage?

#17

motors.vex.com has what you’re looking for. Under each motor, you can find “Locked Rotor Stall Test” data, whosing how long it takes each motor to die under various voltages at stall. Knowing that it’s current that kills motors, you can calculate the stall current for each stall voltage tested, then find what combination of voltage and % free speed give the equivalent current draw.

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#18

This will give you a definitely safe limit. When the motor is actually spinning at several thousand rpm, the internal fan* will vent heat faster than when the motor is stalled.

* Assuming that both the intake and exhaust vents are clear, of course.

#19

We’ve been running NEO’s on our drive train all season, mounted to a plastic gearbox, with routine multi-hour (I think our longest is 5 hours!) practice sessions for our practice robot, only stopping long enough to change batteries or fix anything that breaks. Honestly, the CIM we have for our arm heats up more than the drive train - and we have it almost perfectly counterbalanced, with a brake to hold it in position so the motor is never stalled.

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#20

That is a lot of power! I’m guessing you guys didn’t struggle with defense.