Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I thought very hard about using a large brushless, but I am really not sure how they stand up to shock damage. The large spinning mass is only supported by a light aluminium frame and the bearings are quite small - I think I will wait for Jeff or some other brave soul to prove them in combat before I drop a small fortune on a brushless motor and controller. If the brushless motors can take the punishment, then they could revolutionise spinning weapon design.
It's good to know that some larger bots are using the Cobalt 90; it fits the design really well and the only concern is the reputation for Astroflights cracking magnets. I was planning to run it on around 28V and gear it down a fair bit so the beater has a really fast spin up. Like Arron said, the Mag is over powered and over weight for the job and I would rather put the weight into strong frame construction. I started off the design with 3/4" thick 2024 aluminium side rails
Driving in a straight line - its a new concept for me but perhaps I can practise with the beetleweight version? _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Jul 11, 2006 2:58 pm
andrew
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
whoally double post batman
at a hobby shop near glens theyhad a brushless motor almost identical to jeffs one (think marger version of axi/outrunner stye motor) and it was only 120 for the motor, cotroller not sure but yeah seems cheaper than most brushless options out there and looked descent
i think maybe di a team think tank and get two dewalts or something and something similar to vd3 maybe _________________ Andrew Welch, Team Unconventional Robotics
Tue Jul 11, 2006 3:23 pm
Spockie-Tech Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
Given that the brushless motors usually (The outrunner design) rotate the magnets rather than the coils, I wouldnt expect that they would cope with shock-stops too well.
Probably some form of friction or v-belt drive rather than a positive drive that will transfer the shocks back to motor would be required. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
Last edited by Spockie-Tech on Tue Jul 11, 2006 6:37 pm; edited 1 time in total
Tue Jul 11, 2006 4:37 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
i'm with brett on the friction drive.
even just a bit of rubber pressed against a shaft would probbly do. _________________ Mechanical engineers build weapons, civil engineers build targets
Tue Jul 11, 2006 6:26 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
quote:
get two dewalts or something and something similar to vd3 maybe
DeWalts were up near the top of my list but they have two big problems: The motor shaft is only 5mm diameter by about 10mm long, also it runs at over 20K rpm and would need a large reduction ratio. That's not so hard on a big disk but on a beater, the driven pulley is almost as big as the weapon and will get mangled quickly. If the DeWalts ran at 10K or less, I would use them for sure.
I looked at quite a few brushless motors and the Hyperion range looks the promising for combat bots. They have an extra ring bearing that supports the housing and (possibly) stops it from bending. More info: http://www.aircraft-world.com/prod_datasheets/hp/z40/z40all.htm
The problem with all the brushless motors and friction drive is the tiny shaft (only 5mm on most) and the equally tiny bearings that will not take the sidways load from friction drive. Then there is the problem of driving the beater, which isn't exactly round _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Jul 11, 2006 7:24 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
look for something called a neumotor ORK (out runner killer). i hear they are basically the best brushless you can get. period. _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Id really like to know how they spin those things . . . Seeing as the controller I got was the biggest avalible at the time and obviously wasnt enough. _________________ Jeff Ferrara
fb@ffej.net
ffej.net
Tue Jul 11, 2006 8:17 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
I believe the Torcman's are advised to run on the SpeedyBL controllers, which is an open source brushless design. But unfortunately, the designer of the SpeedyBL's passed away just a few weeks ago.
If your an OSMC mailing list member, you may have seen this already posted.
quote:
Sad news that was posted in the lrk-torquemax group by Soren Kjaer Nielsen:
Jo Aichinger, the father of the do-it-yourself brushless Speedy-BL
controller family (www.speedy-bl.com), died on Saturday, April the 8th:
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
That's another thing that worries me - the controllers cost as much or more than the motors and they can fry just as easily as normal ESCs. The NEU motors are looking like the equal best choice although I still don't like the small bearings and small shaft. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Jul 11, 2006 8:26 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
You could always dive into the world of DIY brushless speedo's..... I'm sure Jake is just waiting for an excuse to build one _________________ https://www.halfdonethings.com/
Tue Jul 11, 2006 8:28 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
So what about it Jake? I might just be in the market for a shockproof potted ESC after the Annhilator, or even earlier... _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Jul 11, 2006 8:31 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
i remember seeing the prototype controller for a "special" motor a while ago *prod prod*
if the designs open source and you can buy circuit boards for them ill make em if you want. soldering is the easy part _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
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