Remember to check Vex’s Load Ratings Guide for the VersaPlanetary whenever you use one.
Also, don’t use the 10:1 unless you absolutely have to.
1 Like
yup, you’d only want to use one to hang if you have a system that won’t let it stall. Our 2019 robot climbed fast, and the driver only had to hold the button down for perhaps 1 or 2 seconds.
Best motors for a climber:
Brushed: 775Pro
Brushless: NEO550, NEO, Falcon 500
FTFY
3 Likes
Hummm… Don’t think I agree with you. I love the packaging and performance of the 775Pros. However I am not sold on them for drivetrains unless you are planning to never deal with pushing matches (either when defending or dealing with defence) as they simply cannot cope with stall. Full power stall will melt the plastic mounts on the brushes in a very small number of seconds. If that does not kill it dead, debris will most likely end up in the fan and shear blades off. You can deal with this in software, but then you lose all the pushing matches.
In my vernacular “mechanism” means any part of the robot that isn’t the drivetrain. 775pros can be used for the drivetrain (as has been proven by many teams in 2016-18), but there’s really no reason to anymore with the high powered brushless motors available. But basically any non-drivetrain mechanism can reasonably be powered using one of those four motors
I love the bag motor for situations where you don’t need a ton of power and that might be subject to intermittent stalling, such as an intake. They’re not only light and small, they’re just so darned forgiving in terms of thermal mass.
I wouldn’t use them to climb, though. As of right now, I don’t think you can go too far wrong with a Falcon 500 in terms of power/weight ratio…if you can get them.
2 Likes
Fair enough… To me “mechanism” is any grouping of “stuff” that does a function and as such the drivetrain is not only a mechanism, it is the primary mechanism.
I also completely agree they can be used. However they come with a huge “you must manage stall” requirement that makes them a poor choice for a team that does not have good software skills. 775Pros and generic software library drive setup will not be a happy making experience.
I also would not put Falcons on the list until they are actually available and have at least a seasons worth of real life experience. I am not going to design in a motor I can’t even get yet and as of today Vex is saying shipping Feb 28th. Part of that is the magical Canadian delay. Buy them to play with absolutely, commit this years robot design to them, not so much.
I also am somewhat twitchy about the integrated packaging. If I smoke a motor I an out the controller and encoder which makes it an expensive opps.
We’re planning to use NEOs, mainly because we made a very large investment in them, next year we plan to use Falcon 500s after we see how they perform this year. A 775Pro drivetrain definitely isn’t a direction I’d point people to either although teams have shown how they can still have a drivetrain with them and do well.
We’ve used a 775 Pro on a 100:1 Versaplanetary gearbox for 3 years in a row. I don’t remember the exact spool sizes but they were in the neighborhood of 2 inches in diameter.
1 Like
We are using a cim motor with some crazy contraption we milled to have a maximum theoratical lifting capacity of 1000 pounds. In years past we have used a combination of 775 pros and redlines with various gearing to them.
We were able to 4 bar climb onto level 3 last year with 2 total 775 pros with independent gearboxes. Gear reduction was about 833:1 IIRC. Took a few seconds and the 1/2Hex gears and shafts had to be made of of very high strength steel to withstand the high shear stress and fatigue loads. The 775pros never got hot in that amount of time but peak current draw was over 40amps so if the mechanism got stuck on the platform (Which it did 
) it would quickly pop a breaker and fall on itself. this would break something 90% of the time lol.
What is the deal with the 10:1? We have yet to have any problems at all? Bag and 100:1 has been a go to for climbing with a winch pull.
It has a tiny little 8 tooth sun gear, tightly constrained by three 32 tooth planets that nearly interfere with each other. If the gearbox gets a shock load, especially in conjunction with a load lateral to the shaft, something is likely to give.
4 Likes
Am I wrong in my thinking? What is your target for climbing speed and distance? Any motor can climb with an appropriate ratio.
I speculated that with a swinging hanger, Alliances will not want severely fast climbing for fear of damaging another member.
We targeted worst case about 20” in less than 3 second. Only a few inches should be under the full load. If my numbers are correct, the NEO550 @100:1 wt 2"Dia. meets the specs, but I can’t believe it. And as other mentioned, my biggest fear is the 10:1 stages of the Versa gearbox.
You’re right that “any motor can climb with an appropriate ratio”, it’s just a matter of determining how fast you want to do it. I think your calculation there looks fine for a sub 3 second climb, but as you mentioned as well as others above, it can by risky to do this with a VP gearbox. If you built a custom gearbox for this application it could very well work though!
As a side note, we did stall a NEO550 at Capital Ri3D and it let out a nice puff of smoke. It didn’t die fully but I wouldn’t trust it to run at full efficiency.
2 Likes
Thanks for the info on the 550. Was the smoke immediate or approximately how long?
A NEO 550 stalling at 12V will smoke in a few seconds. You should treat it like a 775pro.
3 Likes
Yup it was pretty much immediate, maybe 2-3 seconds tops?
We smoke pairs of 550’s in our 2012 shooter whenever it jammed. I don’t recall how long it took but is was short enough that it was difficult for the driver to know about the jam and take his finger off the shoot button.