Boner

[typhoon_driver]

Update - Post champs strip down

Not an overly successful champs for me due to a few let downs however it was a fun champs none the less I enjoyed myself and it was good to catch up with everyone.

Spent a couple stripping down boner this evening to see what was good and bad post champs. At the end of the final white board, the drum and drive didn't work and it was essentially dead in the water.

The good
- The batteries are all in good condition although I wouldn't believe the figures that turnigy quote for their nano series. Divide the C discharge ratings by around 10 and you have the genuine figure
- The turnigy 85a speed controllers that I reprogrammed are still in one piece and work well. I can easily see these being the standard for featherweights now
- The body is all in one piece with no real damage bar the self inflicted damage on the top after it rotated into the drum
- The drum spins just as freely as ever, in fact better than it ever has
- After replacing the brushless motor shaft it's still spinning perfectly
- I didn't burn out a brushless speed controller!

The bad
- The gimsons........well I managed to nacker 3 of the 24v motors, all three went "crunchy", sounded odd and then finally nackered themselves (in two cases they went bad before they had even seen battle!). I poured the carbon brushes from one out of the cooling holes of one of them. The gearboxes are still in one piece and rotate freely enough. I get the feeling that the motors are no good being hard mounted with the all metal gearbox, it's basically all too stiff for what boner puts it through (vertical shocks)

Pics to follow.

[RogueTwoRobots]

I get the feeling that the motors are no good being hard mounted with the all metal gearbox, it's basically all too stiff for what boner puts it through (vertical shocks)

I came to the same conclusion with the GR01s I used in Drumroll last year. Even though the GR01 assemblies are Nylon, everything was so rigid when mounted that there was no 'give' in the setup and, although it doesn't hit as hard as Boner, the shocks going through Drumroll were not being absorbed in any way by the drives. Since going back to standard drills and mounting methods the problem hasn't resurfaced (just a different drive problem now).

All in all though, it's pretty good going. Coming out of the event with just the drive motors being the issue isn't the worst result possible.

[blazerbotics]

Beauty had the same issue with the Gimson, the gearbox seem fine but the motor failed (and took out 2 speedos along the way).

[Mouldy]

Being metal isn't the problem, 720 had some massive hits and the gearboxes are fine... You get what you pay for though... Banebots are better.

[typhoon_driver]

The gearboxes are fine. It's the motors that haven't lasted and that's what I was getting at, it appears as though the 24v gimson motors aren't great at take the shocks

[typhoon_driver]

Although saying that, I'm not using them again

[Eventorizon]

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?

[ewan]

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.

[typhoon_driver]

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.

[typhoon_driver]

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

[typhoon_driver]

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

[joey_picus]

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!

[typhoon_driver]

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

[ewan]

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!

[typhoon_driver]

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