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Ah of course. Now you've said that, I remember seeing some data logs (I think for 360's brushless) showing the low continuous current consumption after the initial spin-up period.
The drum spins much more freely now that I've gone back to needle roller bearings, but I'll make a point of lubing them regularly nonetheless.
Quick Update
The belt for the drum arrived today from Technobots, and it's a perfect fit. No tensioners required!
Just gave it a quick spin-up and I'm happy and impressed with the brushless configuration. The drum could be a problem though.
Despite appearing to be balanced when spun by hand, it starts to vibrate and bounce considerably when the throttle goes past about 20%. I reckon this is the same issue of dynamic imbalance that Calum experienced on his drum that just had two teeth offset at 180°.
I had hoped it wouldn't be too much of an issue having three teeth at 120° intervals but seems that's not the case.
Worst case scenario, I can run it at the champs and just ramp up the throttle when I'm about to hit an opponent, but I think it's worth seeing if I can get another tooth made and add it to the drum in the same arrangement as the old drum, so: V---^---^---V
Back out to weld the armour back together, but will have some pictures and possibly a video later.
Had a feeling you'd have that problem... Get a video :)
You will need to get a new drum made I think
Yeah, either a new drum or possibly a beater.
Will save it for after the champs though. Don't have the inclination to rush something beforehand, or the cash for that matter.
The other way of trying to get around it would be to weld on the inside a weight opposite the tooth. Then it will be statically and dynamically balanced. The weight would only have to weigh roughly what the extra material on the ring weighs.
Even if you can't get one welded in the center tooth of the drum, two on the outside teeth would stop the bot from wobbling sideways as the imbalance would be in the center of the drum only. The bot would bob up and down instead of side to side.
O and I would initially do a small tack weld to hold the weights in place. Spin it up again and check it all out. Then if it doesn't work, a large chisel and hammer and some brute force should remove the weight.
Actually it could be welded on the outside, just to the side of the ring. Although it wouldn't be as neat. It obvious I'm thinking on the spot here?!?
Haha, just a bit. I've actually been thinking along the same lines as you though. I can't weld anything to the inside since the endcaps are welded in place, but I'm thinking that welding on some chunks of metal on the outside is worth a shout. Looks aren't important so no worries there :)
Glad I've got the robots ready quite early this year, leaves plenty of time to faff around with things like this!
Do you need your Ali drum back? Haha.
Hope you get it sorted, Drumroll deserves a decent shot, especially with all the upgrades.