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Looking at possible bosch 750 drive for my next heavyweight or e150 mags, just hoping for info on gear ratios and top speeds of robots,
new design is an old school flipper design with a laucher style arm with heavily angled sides and a large snow plough scoop like ceros.
Have looked at kronics, eruption and mantas designs extra photos and gear train info very welcome, very interested in rippers and toxic drive systems also
seperate note mega wotty has been orderd for ceros
What voltage are you running on?
What is the wheel Dia?
Turb runs, 260mm wheels at about 8:1 and 22.2V Lipo.
Probably 100mm blue twin wheels at 6s
Sometimes the oldest links are the best links
http://howto.killerhurtz.co.uk/calculator.htm
What is the rated rpm at 24v I have seen two different stats for Bosch 750
3300rpm. And 4100rpm
Big difrerence
http://howto.killerhurtz.co.uk/bosch.htm
One is the nominal operating speed, the one it's rating and duty cycle is based on, the other is it's peak if you just stick 24v across it.
Bosch GPA 750W = 4100rpm at 24Volts
http://howto.killerhurtz.co.uk/calculator.htm
so you should base gearbox calculations at 3300 rpm as this is realistic figure when on slight load
not the figure in the killerhutz gear calculator
The figure in the calc is changable I believe rather than fixed.
To be honest you are more interested in ability to accelerate than top speed, I'd pick something between the two, and also look at what others have done.
I know the general rule for Kart wheels on 24v was about 10:1 for a 2WD bot.
I heard the rule of thumb was take the wheel diameter you are using in inches then this is your minimum gear ratio ie. if using 6 inch wheels use a minimum of 6:1 ratio.
e30 400 ampflow motors look pretty good, slight more rpm and heavier then bosch but should be more available and are smaller in size but,
do amplfow motors need mods like boschs do to be full combat ready don't wont jumping magnets
No mods required.
no mods that's not bad, is there any links for bosch upgrades or are the magnet rings etc all self machined, or can you just drill and tap the magnets in place but I know they can be quite brittle ?
just emailed ellis components for a price for three new motors
No Mods required ? I'm not sure that's the case- both us and Big Nipper run modified Mags, I've had the magnets which are only glued in come loose a number of times in the past. Terry you might have been having more luck with the larger diameter C30 mags that you're running but I wouldn't want to run unmodified 3" Mags.
I have a pair of Bosch 750's brand new and unmodified if you wanted some
How much ed ?
Pm me
Bosch magnet mods anyone
basic mods are to re-glue the magnets and strengthen the clips that hold them, and weld up the front plate.
technobots use to do a retaining clip or something to hold the magnets in place for the bosch also i think the iskra 800w motors are still readily available and don't need mods
couple of last questions,
ground clearance for a hw - 5/10mm
125mm blue wheels bearing boys ?
mounting bosch 750 on face plate it looks like it would benefit from a rear mount as well ?
Yes - 10 would be top end.
Yes - used these in Apocalypse.
Yes - a must to hold the motor together.
CURRENT GEARBOX IS
1st stage 12-30 =2.5
2nd stage 20-40 = 2
not sure if to run the shafts at different heights form the centre off the plate to make the gearbox more compact
also might change gear sizes to use multiples of the same gear if possible
5.1 = 9.6mph
or easier gearbox 4.1 = 12.1 mph (15/30-15/30) ratio
Remember to take into consideration the amps being drawn at the different ratios. If you can get away with it I would say 4:1 would be preferred, as your aim is to get opponents to flip the extra torque may not be so needed. Another option could be 5:1 and run a slightly higher voltage?
4:1 will be fine, its just when people are gearing for 20mph and wondering why their burning out motors it becomes an issue!
still mulling it over o gear ratio don't want something to slow or putting to much load on the motor research is king,
wheels rs / bearing boyz or seems like a lot of heavies use robochallange wheels
sitting here surrounded by lots of printouts sketching designs on paper (old school) hate google sketchup just confuses me
anybody got a legal ish copy of autocad knocking around because that I can use ?
Sketchup has an addon for gears. Makes life much easier if you're trying to design your own gearbox.
http://www.fightingrobots.co.uk/atta...845288&thumb=1