Buggy BAG Motors

[Bochek]

I'm seriously impressed by the speed of the response from the people at VEX!

Fingers crossed ours are working perfectly so far!

- Bochek

[Jared Russell]

For both of our problematic motors, we ran for several hours before the issue appeared. Once it appeared, we observed a ~1 in 5 chance that the motor would not start from a given stopped position. The motors were assembled and disassembled from their respective mechanisms/transmissions several times as well before the problem arose, so it is possible that some combination of operation and handling contributed to the issue.

[ajlapp]

We've had two go bad more or less immediately after assembling them to a Versa and running them lightly. Another has been in use with no issues.

[ttldomination]

Originally Posted by Jared341

For both of our problematic motors, we ran for several hours before the issue appeared. Once it appeared, we observed a ~1 in 5 chance that the motor would not start from a given stopped position. The motors were assembled and disassembled from their respective mechanisms/transmissions several times as well before the problem arose, so it is possible that some combination of operation and handling contributed to the issue.

Nice to see the quick replies.

Our issues have also been with motors that seen extensive use for a few hours/testing sessions, and then they just conk out.

Oh well, nothing to do until after our week 1.

- Sunny G.

[Paul Copioli]

We believe this is isolated to a specific date code. we are still investigating, but it will be very helpful to let us know your date code. The code is
"YWWD" - Year, Week, Day all numbers. The last two letters are the actual factory. All of our motors are made in the same factory so that part of the date code is not relevant.

If you can e-mail me paul_copioli [the at symbol] vexrobotics [dot] com your date codes of bad motors, then that may help expedite the process.

Thanks,
Paul

[Jon Stratis]

Paul, would it help if we organized an informal check of motors at some of the regionals? I know my team isn't using the BAG motor this year, but I want to check ours the next time I'm at our build space (if only to avoid issues if we try to use it in the future), and it sounds like it would be quick and easy to walk around the regional with a multimeter and check any BAG motors that are there.

[Kevin Sevcik]

We're using a three and have some spares as well. I don't think we have any problems. The 1:1 BAG on our shooter tops at 11000 RPM, but I figured that was from loading. I can't check any till Lone Star, but I'll be sure to check them there.

[IndySam]

Anyone else have further problems? We have had 4 out of 5 fail.

Vex customer service has been great and we have more on the way.

I'm hoping we have just had bad luck and others are not having as many troubles as ours.

If people tell me they worked well for them during week one I'll be much happier.

[sdcantrell56]

Originally Posted by IndySam

Anyone else have further problems? We have had 4 out of 5 fail.

Vex customer service has been great and we have more on the way.

I'm hoping we have just had bad luck and others are not having as many troubles as ours.

If people tell me they worked well for them during week one I'll be much happier.

We've had the failures and have since swapped everything to 550's which brings up another problem in that there are no piloting features for the 550's on the versaplanetaries so it takes a great deal of effort and fiddling with alignment to get the planetaries to not bind.

The low prices are great but I have to say all of the problems encountered thus far are not leaving a great impression for anyone I have been in contact with.

[CalTran]

Originally Posted by IndySam

Anyone else have further problems? We have had 4 out of 5 fail.

Vex customer service has been great and we have more on the way.

I'm hoping we have just had bad luck and others are not having as many troubles as ours.

If people tell me they worked well for them during week one I'll be much happier.

I checked the three I had on had with the resistance check that Paul suggested, and all three of them work (Highest reading I could get was 80 ohms). Unable to check the 3 that may have been buggy, as they're inside the bag itself.

[R.C.]

Originally Posted by IndySam

Anyone else have further problems? We have had 4 out of 5 fail.

Vex customer service has been great and we have more on the way.

I'm hoping we have just had bad luck and others are not having as many troubles as ours.

If people tell me they worked well for them during week one I'll be much happier.

Same,

We had 3/3 bags just fail over the course of the regional. Just ended up switching to RS Motors/AM motors.

Will be sending motors back to VEX sometime this week.

-RC

[Paul Copioli]

Originally Posted by sdcantrell56

We've had the failures and have since swapped everything to 550's which brings up another problem in that there are no piloting features for the 550's on the versaplanetaries so it takes a great deal of effort and fiddling with alignment to get the planetaries to not bind.

The low prices are great but I have to say all of the problems encountered thus far are not leaving a great impression for anyone I have been in contact with.

Sean,

I would like to know more about all the problems you have been having with the VEXpro items. Can you please either PM me or e-mail me at paul_copioli <the at symbol> vexrobotics.com? We have received very little complaints about the VersaPlanetary this season so I am interested in what problems you are hearing about or witnessing.

The Versaplanetaries purposely do not have pilots because the motor shaft is supposed to be the pilot. If you follow the procedure in the user's guide you should not get any binding between the motor and the gearbox. This motor mounting technique is very common with industrial servo motors and does not require a motor pilot.

With regards to the BAG motor issue, we are still working on root cause analysis, but the leading suspect is too much tension on the automatic motor winding machine. This can cause elevated stress in the copper wire. We have not finalized our findings yet, but we are working as quickly as possible on getting to the bottom of this problem. However, we have not received any motors back from customers yet and we are having a hard time reproducing the problem here. As soon as we get more failed units we can try to get to the bottom of this as quickly as possible.

Paul

[FrankJ]

I have to say I love the vex planetary gearboxes. Not having to press a gear on the motor using a force just lower than what is required to bend the shaft, turning the motor into trash is great. You do have to use an allen wrench in good shape to tighten the set screw though.

To stay on topic, we have not unbagged our bag motors yet.

[Dan 1038]

Paul,

Thanks for the quick reply to everyone and the updates on this issue, awesome customer service! I will try to locate the BAG motor we removed a few weeks ago due to a similar failure and ohm it out to see if it has the issue.

[Jared Russell]

We also had a couple more BAG motors fail over the weekend, and replaced them with RS550s. There is now only one BAG on the machine, and we will swap it out during our unbagging window before our next district event (since we bought all of our BAGs in a couple of bulk purchases, the odds seem fairly high that it will fail eventually).

We 3D printed ABS spacers to help pilot the 550s into the VersaPlanetary motor plate since even when we followed the directions as closely as possible, we were unable to obtain a gearbox that didn't bind, make clicking noises, or wobble when run. The issue (I think) is that mounting the motor concentric to the motor plate is difficult because the holes are too large to pilot the RS550's M3 bolts. Leaving the motor bolts loose ensured that we ran without binding or clicking, but resulted in a vibrating motor.

Regardless, with the spacers, installing a 550 is a breeze and everything runs smooth as butter. The VersaPlanetaries are a fantastic gearbox once you get them together! There's a reason 341 has 5 of them on our robot

I realize there is nothing you guys can do about the BAG motors without some failed units, so I will make some time this week to round up our problematic ones and send them your way.