Lithium cell tests

[storm]

Ditto what Stu said - we used the same cells in Vortex and whilst Im sure its opponents wished it would only spin up 6 times, it would happily do a 3 min fight... what is the tension like on your weapon drive system, are you making the Mag work harder than it needs to ?

the cells in vortex came out warm but that was about it

Somethings wrong there...........

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

[kane]

Leo, the FRA is making its decision on the use of these batteries based on results from the Lithium testing John Reid is currently undertaking.

This was posted in the http://www.fightingrobots.co.uk/meetings.htm

[leorcc]

Ok, thank you.

[typhoon_driver]

Ed, I think there are a few reasons that I am not getting full performance out the nicads.

They have been sitting in my garage since the last UK champs and after a few cycles I am noticing a difference in their performance. What doesnt help is that my charger is relatively cheap and can only do a max charge of 600mA. So I manage to get one cycle done a day with them

I am using a 20mm timing belt on the disc and have a tensioner in place. This was a quick job with a piece of aluminium bar I had sitting around. I am going to replace this with one of the slippy plastics to reduce the friction. I may reduce the diameter of the bar as well to give it a bit more slack.

I have however noticed that running normally, without any load, the mag gets hot after around 4minutes, is this normal or does it sound as if something is not quick right inside it?

[maddox]

A mag C28 150 runs warm even unloaded after a few minutes.

[terrorhurtz]

buy a shunt off ebay for £10 and find out what is really happening. Stop guessing. Get the facts.

(Message edited by terrorhurtz on May 17, 2007)

[typhoon_driver]

Well I think I have managed to find the facts without a shunt.

I took the assembly apart earlier on and discovered that the hole that the shaft passed through had been polished on one side, in other words it had been fouling slightly on the inside. I turned the shaft of the motor as well and it seemed to snag ever so slightly at one point. Took it to bits and it seems as thought the magnets have shifted around. They are bunched in two pairs across from one another. It also seems as if the armature has been rubbing on the magnets at certain points.

Looks as though I am going to have to reglue them into place.

Thanks for the advice and help btw guys, really appriciated

[RogueTwoRobots]

Nick Martin down in Oz had the problem of the magnets moving as well. IIRC, he found that regluing them only held them in place for a short period of time before theyd come off again, due to all the high impact stresses etc from the spinning bar. He talked about it in his build thread (http://robowars.org/forum/viewtopic.php?t=74&postdays=0&postorder=asc&start= 0&sid=23f9aadcd81ee1d7826f7b3d620e69f6http://robowars.org/forum/viewtopic....asc&start=0&si d=23f9aadcd81ee1d7826f7b3d620e69f6) but its been a while since I read it so I cant remember if he came up with a solution to solve it (think he was looking at something similar to the Bosch mod kits)

He also had problems when trying to reglue it of not getting the magnets lined up properly because as soon as he lowered the magnet into the can, it would just pull against the side before he got a chance to line it up.

If youve got some spare time (when youre not studying ), the thread makes good reading (although it is 130+ pages)

(Message edited by K_C_R on May 17, 2007)

[big_nipper]

We have had the same problem also. Glue does work, he must not be doing it right, the only time it will fail is if you overheat the glue and it soffens too much. What we did was to make some end caps and put these a few mm away from the magnet edges and the fill the casing with glue. Repeated this 4 times to fill all the inside of the casing with glue, then using a file made room for the 2 bolts again and its done.

You must be careful to set the timing correct again after or it will heat up and waste too much power just as before.

We also had problems with the cases twisting (ie altering the timing) causing the same effect. So we have now also keyed the end caps to the case as well.

[typhoon_driver]

Mark, can you recommend a glue to use or with your bog standard araldite out of B and Q work?

I have heard scotch 2216 mentioned in this article here http://www.madoverlord.com/Robots/MAGMOTORREPAIR.thttp://www.madoverlord.com/Robots/MAGMOTORREPAIR.t but have not been able to source a UK supplier.