It looks like you can no longer buy Bag motors from vex. (https://www.vexrobotics.com/217-3351.html)
Does anyone know if there are any other sights that sell bag motors?
I think the BAG is a Vex-specific product. If any suppliers want to take a crack at a “remake” of the BAG, I suspect it’s a custom variation of a CCL PM15R motor.
(Alternatively, AndyMark could put the 9015 back into production if a “new” design is too much of a hassle. It fills pretty much the same niche as the BAG unless another similarly-powered motor is allowed to run with 2 to a controller under R504.)
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Cue the underground marketplace for BAG motors… I got the goods, for a measly supply/demand markup of course. What’s it worth to you?
Spoilers...
Is offseason-CD really going to make me add a /s…?
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Bag motors are not really super popular anymore anyways. Neo 550s are the best bet for a bag-ish motor
The interesting thing is that it is discontinued in the US but not in other places.
It looks like they are still up for Vex Canada if you want to buy new ones.
I totally understand a rather niche product that no longer sees widespread usage getting discontinued. But it does bum me out that the BAG (and its predecessor, the Globe Motor) will no longer be in the toolbox once team’s have used up their current supply. Even in the age of higher power, better density, and easier controlled BLDC motors, I think there’s always a potential use case for a super reliable and robust brushed motor. And the BAG was that motor. Even if you released the magic smoke, you could cool it back down and send it back out for the next match and it would still spin.
A salute to a reliable motor. Bad Ass Globe, indeed.
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Agreed! The BAG had one feature that made it quite unique amongst small FRC motors: you could stall it for quite some time without it dying. Take a look at the locked rotor testing data comparing the BAG ( https://motors.vex.com/vexpro-motors/bag-motor ) with the AM9015 ( https://motors.vex.com/other-motors/am-9015#crhpmch ) or the Neo550 ( NEO 550 Brushless Motor - Locked-rotor Testing )
At 12V with no current limit, you will kill a AM9015 or a Neo550 within a couple of seconds, whereas the BAG could last around 20 seconds.
While you should generally avoid stalling motors for extended periods of time (especially without a current limit) there are plenty of use cases where high power stalls of a few seconds are useful, and the BAG is a great motor for this.
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Sean’s post above covers most of my thoughts.
Captain Obvious might also observe that there’s a minimum number of BAG motors that can be produced and shipped at the cost we’ve come to expect, and availability of smaller, lighter, more powerful brushless options has reduced demand for the more robust brushed motors. We’ve voted with our orders.
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One more benefit of bag motors is you can run 2 on the same controller.
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I have always wondered about this. Of course the ability to drive two would have been more useful in the past, but is there really a use for driving two BAGs when we have many single motors that could fill the same role?
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Being able to drive two motors from the same controller is not generally done to get more power out of a given speed controller, because you could instead use just one of the more powerful motors to achieve the same thing. Rather, it’s done if you want to create motion in two different places, and you are ok with both motors running at the same voltage at the same time. For example, if you had a roller claw with a left and right side, you could run them from a single speed controller with one BAG per side
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With the important caveat that running two motors at the same voltage does not mean that they’ll run at the same speed, especially if one faces a higher resistance than the other.
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Like many teams we were gifted “stuff” when we got up and running in the fall of 2015. Vintage stuff.
I’d love to see somebody with time on their hands and a tendency to hoard attempt a “STEMpunk” build for a current game, using all motors and electronics from before say, 2014. Ten years is a long time in robotics. Throttle motors, Jaguar controllers, BAG motors.
I imagine the radio would have to be newer tech. Darn vacuum tubes and all…
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Could this not have been done with PWM Y cables (or now follower functionality)?
(Not criticizing this method at all. Just trying to understand the advantage.)
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My understanding is it was more to have more motors then PDP slots available.
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How big is the toolbox, especially in 2024? Far as I’m aware, options for interfacing with a BAG motor were the VersaPlanetary or one of a few press-fit pinions made for its output shaft.
I certainly get wistful for simpler brushed-motor times too, but the BAG was always a pain to work with for that reason.
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Runnings 2 BAG motors off of the same controller meant that, out of 16 slots on the pdp, you only used one up. It’s not as needed now with the 20 slots on the pdh, but still cool to have
I’d imagine there are a lot of teams sitting on piles of these that they’ll never use. Maybe this thread could serve as the BAG trading post?
Just give it a sniff test - you’ll know if it has been burned up at one point. A tough motor to smoke but once you do it you’ll never forget that smell.
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Has anyone actually used a BAG motor in the last few years? I never thought they would be popular again. I’ve got a drawer full of them if there’s going to be a bull run in 2024.
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Used one for an intake in 2022 because the 2020 robot used one and no one wanted to change it.
Used one for our original roller claw this year because no one could figure out how to attach a NEO550 to a VP. It also served well powering a sword system.
I am willing to guess you might get another example of “CD bias” here.