small banebot motor with 64:1 gearbox

[burkey_turkey]

Im just wondering if anyone has tried using the small banebot motor with the 64:1 gearbox. We have a very light arm this year, and instead of using the 'pimp CIM' (the one with the spring and stuff) we thought we might be able to use the small banebot motor with the 64:1 gearbox. I saw some stats on it on the banebot website but i really dont know what that means or trust my own calculations. So, if any teams have experimented with this motor, i would to hear what your opinions on it are. How strong is it compared to other motorts in the kit? does it pull a fisher price and melt when it stalls? any comments on the motor would be apreciated, qualitative and quantitative.

[DanDon]

From our observations, the motor backdrives. And, for future references, your "pimp cim" is actually called a Minibike motor.

[DonRotolo]

It's pretty stong - we had a hard time stopping it from spinning. It rotates about 3-1/2 times per second, and that 3/8" shaft, with both a 1/8" keyway and a tapped hole on the end make it easy to mount to. And, the gearbox has those nice mounting holes... We'd been considering the globe motor - it runs at a more suitable speed for what we're doing with it - but went with the Mabuchi just because the 64:1 gearbox & shaft is so nice to work with.

We ran ours in for about an hour, no load current draw went from almost 2 amps down to just over 1.

It does backdrive, can be a disadvantage in some applications.

Don

[burkey_turkey]

sorry, but im new at this, so when you say it backdrives, does that mean that if i had the motor connected to some arm (via chains) and i lift it up and stop it, pressure on the motor can make it wander backwards and fall some? if i put just a little bit of current through the motor or something would the problem be fixed?

[Salik Syed]

No, it is probably not going to be feasible to apply a "small amount of current" to keep it from moving.
Different angles of the arm result in a different amount of force being applied in the downward directions. Thus one amount of current may hold it in place, but at a different position it would do nothing or even cause the arm to move.

The only feasible solution is monitoring arm position via a Pot (recommended!)

or using a locking worm gear transmission ( this will work but I wouldn't implement a worm gear simply due to the fact that it locks... maybe if you need a massive reduction with small amount of space

[Cody Carey]

Originally Posted by burkey_turkey

sorry, but im new at this, so when you say it backdrives, does that mean that if i had the motor connected to some arm (via chains) and i lift it up and stop it, pressure on the motor can make it wander backwards and fall some? if i put just a little bit of current through the motor or something would the problem be fixed?

http://www.chiefdelphi.com/forums/sh...&highlight=PID


That thread should help out a bit


But in a rough case, yes, you can run the motor a bit and keep the arm in a fixed position, We've had to do it in the past.

[burkey_turkey]

one final big questino i have thats been neither confirmed nor denied, is if the motor mentioned in these posts can burn up real easy like the fisher price motor when stalled. This could be a real problem, so im trying to get all the info i can before we make a decision. thank you everyone for your contributions so far, you dont know how helpful youve been, honestly.

[Jonathan Norris]

Originally Posted by burkey_turkey

one final big questino i have thats been neither confirmed nor denied, is if the motor mentioned in these posts can burn up real easy like the fisher price motor when stalled. This could be a real problem, so im trying to get all the info i can before we make a decision. thank you everyone for your contributions so far, you dont know how helpful youve been, honestly.

I wouldn't be surprised for it to burn up just like the FP motor, most small high RPM motors will have that same problem. This new motor looks just like a weaker FP motor. You would be better off with approx. twice the torque with the FP motor, and a 42mm banebots gearbox. I am liking this 256:1 42mm gearbox to attach a FP motor for an arm.

[burkey_turkey]

thats the 550 motor not the 540 that was included, is that legal?

[jgannon]

Originally Posted by burkey_turkey

thats the 550 motor not the 540 that was included, is that legal?

The motor is not legal, but the gearbox that is attached is legal. You may be able to use the FP motor in that gearbox.

[meiv4]

The FP motor will fit in the 42mm gearboxes. you either have to pull the pinion gear off the motor that comes with the gearbox or buy another one just get the right one for whichever box you get. The shafts are also a hair long so you will need to add some small spaces when mounting or cut down the shaft. One idea we were looking at was getting 2 of the 27:1 gearboxes and then using both FP's to dual drive a worm gear for our arm, although almost every member of the team hates the FP motors, which is not cool since a good 3/4 of them are freshmen and have never seen them in action.

[burkey_turkey]

so one last question in my never ending struggle of finding the right arm motor, can the fisher price mini bike motor can go through the same gearbox that the CIMs go through? if this is true than my work is practically done for me:

2700 rpm -> 45rps

12:1 gearbox -> 3.75rps

the 4:1 attachment -> ~1 rps

some procket reductions (1 or 2) and its at a reasonable speed!

the minibike motor seems like its CIM ish enough to fit in one of those, but we are already using both of our gearboxes for the drive and cant test to see if it works cause its already assembled. it would be nice to know if it would work before we buy the gearbox.

[Cowmankoza]

Team 1251, is using 2 of the banebots motors with their 125:1 planetaries (lovely numerical coincidence). just to play it on the safe side

[Joe Johnson]

I am a big fan of the Banebots gearboxes. They are great little power packs. But I am worried about them too.

I am working on some analysis that is intended to predict the max torque I would recommend for use on the 42mm and 36mm gearbox.

Note that just because the ratio is available it does not mean that it would be safe to use all the torque available (if you stall the output shaft or impact loaded the gearbox for example).

As I say, I am working on the final recommendations, but my I am leaning toward talking teams out of the 256:1 ratio on the 42mm gearbox and the 125:1 on the 36mm gearbox in applications where the motor can be driven to stall.

More to come.

Joe J.

[Dan Richardson]

Originally Posted by Joe Johnson

I am a big fan of the Banebots gearboxes. They are great little power packs. But I am worried about them too.

I am working on some analysis that is intended to predict the max torque I would recommend for use on the 42mm and 36mm gearbox.

Note that just because the ratio is available it does not mean that it would be safe to use all the torque available (if you stall the output shaft or impact loaded the gearbox for example).

As I say, I am working on the final recommendations, but my I am leaning toward talking teams out of the 256:1 ratio on the 42mm gearbox and the 125:1 on the 36mm gearbox in applications where the motor can be driven to stall.

More to come.

Joe J.

Heh, I wish I would have read this post before purchased multiples 125:1 gear boxes. However they should never even close to reach stall so i'm not overly concerned. Impact moment might not be as friendly as it needs to be tho.