Boner

Although saying that, I'm not using them again

Could you buy one of the various Banebots motors and put them on the GR02 Gearboxes? Or do we run into the whole metric to imperial problem?

Gary and others, if you get a chance please could you message me with the exact nature of your motor problems? It would be useful to know if the problem is consistently isolated to the motor rather than the gearbox, one way of checking this is seeing if the motor shaft (when removed from the gearbox) is any stiffer than you would normally expect and/or if the no-load current is much greater than the rated value (1.4A for the 12V at 12V, 0.85V for the 18V at 18V and 0.7A for the 24V at 24v). Also if there are any other signs of damage or visible stress points.
It is possible that lack of support for the rear of the motor body is contributing to problems in the shock-environment of combat, though I would want to be sure of this before investing in a remedy.

All three motors had a high pitched whine/crunching noise before they went. One of them exhibited this behavior during drive testing before I packed the car (swapped that one out at the last minute before i left Aberdeen, had to use it again at the champs).

All the motors do not now spin freely and none of them rotate when hooked up to a power supply. I was running them on a 6 cell lipo, so not over rating them and used the 36:1 gearboxes as the wheels were the 124mm ones from banebots. Nothing out the ordinary there.

All the gearboxes look fine, gears all spin without binding.

I'll see about digging the nackered motors out the bin and take the back end off to see what actually went in them.

edit - I should also mention that i broke the motors in on no load for 10 minutes on a low voltage, then a high voltage before using them. Something I don't normally bother with drills but I wanted to make sure everything was squared away this year pre champs.

Well I think it's fairly conclusive as to what occurred in the drive motors in boner. As the picture below shows, one of the copper brush holders snapped. The rest of the brush holder was then running against the commutator. I'm assuming that was what the large screeching noise/crunching feeling was ( the death cries of a motor). I find it incredible that this occurred before I got into battle with one of them. When running them in that state, the two copper elements heated up and burned the copper wire right at the crimp point. The rest of the armature was fine.

http://i.imgur.com/vGZ9gJW.jpg

Oh and the copper on both parts was quite obviously heat discoloured.

Where would you go to get better build quality 550 size motors? I've looked into it occasionally for whenever I manage to get my arse in gear and get a featherweight built because I don't know if I trust the stock motors on the Gimsons too much (something this seems to bear out!)

Also, on a totally different subject, does Boner have a self righting mechanism/way to reverse the drum as such, or does that consist largely of hitting the nearest robot to flip yourself back over? :) Good luck with the upgrades though Gary, hopefully your Boner can stand proud and victorious next year!

Boner is essentially retired from main competitions. Got another machine in planning atm. And to answer, no self righting mechanism.

I'll send you over three 18V motors Gary which hopefully you'll find some use for. They're from a different manufacturer and as far as I'm aware haven't seen the same type of failure before.

The same applies to anyone else who thinks they've got similar issues with the 24V motors, if you can either take a picture of the brush holders as Gary has done and message it to me or send the motors back to the address here with a return address included then I'll have the same number of 18V replacements sent to you.

Sorry about the thread hijack!

No bother Ewan. As I said the gearboxes and shafts have held up fine. It was the motors that let me down.