hey guys just wondering what ratioi is reccomended for the gear box ina 12v version?? 25:1 ??
ty for all the help
-duff-

yeah tahts what ill be using for next orbit drives, already got two of em, i went off the ratio of a drill gearbox as its close to that and they do pretty good as far as speed/torque go.
_________________
Andrew Welch, Team Unconventional Robotics

That is an open question; it depends on your wheel size. If you have larger wheels then you definitely need more reduction. On the other hand, more reduction can mean more gearbox stress.

Personally, I like 16:1 and wheels under 75mm, but that's just me!
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

You can try different ratios and wheel sizes in this calculator http://www.architeuthis-dux.org/torquecalc.asp Acceleration is more important than top speed, IMO.
_________________
So even the rain that falls isn't actually going to fill our dams and our river systems

A bit off topic and digging up a slightly dead thread but anyway.
2 questions.
1. for featherweight would a 12v bane bot motor be about the best 12v option around ( my design needs between 14.4v or less motors)
2. Can an ibc handle 2 without magic smoke ?
(Nominal v: 12v, No Load RPM: 19300, Stall Current: 85A
Kt: 0.83 oz-in/A, Kv: 1608 rpm/V, Efficiency: 70%)

And if that works would RS-775 motors not blow an ibc?
(Nominal v: 14.4v, No Load RPM: 17350, Stall Current: 102A
Kt: 1.09 oz-in/A, Kv: 1205 rpm/V, Efficiency: 70%)

Thanks to anyone who can offer any advice.

They are probably a bit hefty for the IBC.
The legs melt off the FETs at 75A. I'd be wary of doing anything with a stall current more than about 50A.
It will work ok provided you drive really easy with it.
_________________
Mechanical engineers build weapons, civil engineers build targets

i thought so thanks valen. might try and save for a sidewinder or just give up on my design for a while.

Also consider the Victor 885 controllers plus an IMX mixer. They don't have current limiting, but their peak current handling is so high that most batery packs are not capable of blowing them even with a dead short. I used them all last year in Jolt and they were totally reliable, even when motors siezed from mechanical problems. They work out to be $1 less than the Sidewinder and are smaller.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

agreed on the victors. in my almost 3 years of using them never even had the slightest of glitches. despite all the other crap you have to put on them to make them work (which is the biggest downfall) they are hands down the most robust controller.

but in saying that i just got a sidewinder for the new version of my robot, not as much current capability but i think limiting the current to 130 amps will do wonders for my packs and not decrease max power any. and only having to wire up 6 wires will be a dream
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz