Does anybody have any experience with using Direct Drive NEO 550’s? We are planning on using 2 550’s attached to separate flywheels (compliant). The Power Cell will fit through the 2 flywheels. We have a successful prototype however with using hand drills. Will we see a performance drop or increase with a direct drive?
Thanks
Have you measured the RPM of your successful prototype?
I suspect a Neo550 goes faster than that.
Keep in mind that compliant wheels expand when they spin fast so at higher speeds your results may be inconsistent. Also they can fall apart if they go to fast. I would suggest using solid wheels like colsons. A good rule of thumb hard balls soft wheels soft balls hard wheels.
Thank you, I will look into this. I suspected the RPM would be a problem. However do you think the torque will be enough? Is there a need for a gearbox.
Having held that little guy in my hand, I would not recommend direct driving it. It does not have much interia of it’s own and I would be worried about maintaining the speed between shots.
The revs of the NEO 550 are roughly 2x the NEO. Assuming a 4" wheel works well with the NEO, if you used a 2" wheel with the NEO 550, you would have the same surface speed. But this arrangement gives a lot lower angular momentum is going to be much lower from both the motor and the wheel, so I don’t think you will get consistency.
You would also want to check with REV and see if they have any concerns about the motor itself.
Depends on how rapidly you want to shoot multiple PCs. More torque will get your wheel back up to speed quicker after each shot, so your shots are more repeatable.
As an example: my team began testing our shooter using a Mini-CIM motor. Later we replaced the motor with a Falcon 500, which has more than three times the Mini-CIM’s stall torque. We immediately noticed a much tighter grouping of our rapid-fire shots, which agrees with the Falcon’s capability to return the shooter wheel to set-point speed faster.
Edit: sniped by worgren, whose points are spot-on as usual. I can add that my team has experimented a bit with Neo550s and we’re seriously considering them to power some of our robot’s functions, but the main PC shooter wheel is NOT one of those. I hope @Greg_Needel or another REV engineer will join the discussion to talk about the range of applications they had in mind when they launched this motor.
NEO550 was designed as a multi-purpose motor good for all sorts of things, but they really shine for things like intakes, conveyors and mechanisms where space is limited.
From a power perspective they can be used for things like shooters, and arms, but given the selection I would turn to a regular NEO before a NEO550 in those higher load applications.
Overall we look at the NEO550 as a replacement for the 775pro, Bag motor, Banebots 550, and most other non-CIM class motors.
Given the power of the neo 550 and that 775s and smaller have been used quite frequently in bith 2017 and earlier as shooter motors is there some other reason that you dont recommend it as a shooter motor or is it just that you think the regular neo likely packages just as well in those situations and is simply more powerful?
Thank you, this makes much sense. We do have spare NEO’s (and obviously Spark Max’s for the 550’s) on hand. Swapping the 2 out should not be an issue and we will try testing both as space is not a constraint currently. Do you think NEO’s on direct drive will function well? We really just want to skip the gearbox. Just looking for rough ideas and prototyping anybody may have done, obviously no need for guarantees.
Neo motors will certainly have enough torque to perform well in a direct drive shooter.
I’m not a REV employee, so take my comments accordingly. Neo motors have bearings on each end of the stator support tube, one near the face-mounting plate. I think they are 698 bearings, which means the ball size is smaller than that of a 608 bearing, with correspondingly less side load capacity. Someone with better bearing load calculation skills than I have will be able to analyze the Neo bearing capability.
Generally I would recommend direct coupling ONLY if your fabrication method can yield a well-balanced rotating assembly, and very close angular and parallel alignment of the components. If the load is unbalanced, balls in the bearings will hammer on their races and wear them out faster. The safer approach is to remove side loads by coupling to the shooter shaft by belts or gears, with the motors offset.
Thanks, I think this is what we will be doing. However as belts go our team has a bad history when trying to tension the belts and complications arise quickly. I think a direct drive of the ultrahex is what we’ll go for. We have used this method before and it’s worked.
Thanks for all the help, this forum really allows us to find the mistakes we are making earlier.
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