BaneBot RS540 Motors Shorting Out:

[Jack Jones]

What many of your are assuming to be failure due to stalling may be due to the motors shorting out. We had one shoot sparks and smoke. As could be expected, we assumed a hitch in the system might have stalled the motor. We later smelled the magic smoke, but didn’t associate it with the Banes, because we weren’t even running them. Finally, but not until a Victor gasped it’s last smoky breath, and another circuit sputtered and clicked, I’d had enough and proceeded with a second full continuity check. All appeared fine until I wiggled the RS540 leads – Bingo, zero resistance between +12v and the chassis. The other was the same – intermittent short!

Do not suppose the wires we’re tortured, or the connection was cooked – I did them myself.

BaneBots – how prophetic it that?

[MrForbes]

Do you have any idea what caused the shorts? Had the motors been run hard enough to melt insulation, or is there just a mechanical problem with the terminal mounting? pics of what is shorted would be nice

[Jack Jones]

Originally Posted by squirrel

Do you have any idea what caused the shorts? Had the motors been run hard enough to melt insulation, or is there just a mechanical problem with the terminal mounting? pics of what is shorted would be nice

The motors had not been run hard; they had hardly been run - very gentile testing was all we had done.

It is definitely a mechanical problem with terminal mounting lugs. They wiggle in their plastic housing enough to cause an internal short. We are using them in a double-double rack and pinion lift for placing tubes. The motors move up and down with the racks. We used a similar system for Triple Play with FP motors and gearboxes - the FP terminals had no problems. But this year we're using our FP motors in our 6 motor 6WD, so we don't have the option of using anything but the 540.

We just discovered the source of the problem yesterday evening, and decided it'd be a good time to call it a day. Right now the plan is to find the happy place for those terminals and epoxy them in place. We're already using double strain relief to secure the wiring - but we'll take a look at making it better.

The bottom line is that our failure to notice the weakness of those terminals cost us one, maybe two, Victors. We hope that this post will prevent it from happening to sombody else.

[MrForbes]

Thanks for the heads-up!

I just ordered a few more of the RS540 motors, at $3.55 each it's worth it to be able to take one apart and learn more about them. We do have both FP motors unused, might be a good idea to see about installing a BB pinion on one....and also to make sure the RS540 motor wires are well supported, right now they're just hanging.

[MrForbes]

here are some pics of the brush holder and such of a Banebots RS540 motor.

(edit: added "before" picture)

[groves]

***FALSE ALARM***

It must be getting late in the build season! The aluminum racks on our double rack and pinion gets shaved of by our titanium pinions. These shavings fell into awkward areas on our banebot system. Needless to say the electrical short that was happening was not the fault of the motor or bane bot, it was my own fault.

Thanks to squirrel for your sincere concern.

[MrForbes]

Glad to help...and a bit concerned about our own robot, which uses the 36mm banebots gearbox/RS540 motor.

I could not see any way that the terminals could short out, so having shavings in there is a reasonable explanation.

The programmers finally got the 1726 bot going today, the arm now works as it should, driven by that little 540 motor in a 125:1 gearbox, with a pretty well balanced gas spring holding it up. Several students took turns driving/scoring rings, and the motor seemed to work fine, although it did emit a little bit of "warm winding" odor. Should be ok....but we're working on setting up a FP motor on a spare gearbox just in case!

[redbarron]

Titanium Pinions?

[MrForbes]

Originally Posted by redbarron

Titanium Pinions?

Must be one of those high-tech teams, we carved our pinions out of stone!