Problem with bushes as they are often round on the outside to self align, when the motor takes a hit the spring clip that locates the bush in the end plate can fail and allow the bush to pop out of its socket and the armature to pole out.
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Satisfaction is proportional to effort and results.

Updated the bushs with bearings today in the motors. Decided last night after noticing how long it takes for a scooter motor to slow down compared with a motor with bushs.

The bushs on these particular motors where shaped like a bearing so they could probably take a pounding. 8mm ID and 19mm OD so once they where removed just had to drop in similar sized bearings.
Placed some very thin washers behind the bearings to reduce movement inside the motor and put them back together.

The specs on these motors have them as drawing 2.3 amps at no load.
I measured 2 motors in both directions and got readings between 1.8 - 1.5 after the conversion, will tinker some more but thought that was a good result.
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Bots that do not destroy you, only make you stronger.

Proving once again, an ounce of testing is worth a pound of theory..

Good stuff George, how about running some numbers, or even better a real-world test on how long the motors run at say 40-50% load for on one set of batteries first with bushes then bearings.

I bet people would be willing to do the conversion to get an extra 30 seconds of battery life in a fight.
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

When I get some more of these motors will be able to compare with some testing, cant do atm as have have converted both.
Was looking for some theory on the above info.

Curious to know what effect that has on the motors efficiency.
If the motor is drawing 25% less current at unloaded speed then is it a fair call to say it might be 10% more efficient as a total efficiency value of the motor.
Dont know how to link the 2.

Any ideas anyone on the theory of working this out??
freaking maths
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Bots that do not destroy you, only make you stronger.

Robot + Wedge = WIN!
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https://www.halfdonethings.com/

ball bearings are more efficient because there is no(minimal) sliding contact, that's what makes your friction.
wrt efficiency gain under load its probably going to be minimal. There should be no real "yaw" type loads on the bearing itself with a planetary gearbox those would serve to increase friction in a bush set-up and would make a proper bearing shine.

Basically that 25% gain is the absolute best case. The % gain under load will be that decrease in current draw / the amps drawn in total - the no load current

so something like
1/(20-1) = ~5%

that is at full speed.
At lower speeds (and higher powers, where bots spend most of their time) you will see less gain as the advantage of the ball is reduced.

By the same token i'd buy a ball bearing based motor over a bush any time the reliability and maintenance alone does the sell for me.
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Mechanical engineers build weapons, civil engineers build targets

Yep, bearings r good.
On a side note, just placed an order for a 2.4G transmitter and receiver bundle for my Hitec.
The 6 channel park flyer with end pins isnt available yet and thats really the one I would prefer for combat as its smaller, the end pins help keep its profile down and the aerial is on the board so nothing sticks out.
The 6 channel isnt as powerful as the 8 channel but is still good for 1000 feet.
Anyways woohoo, new robot parts on the way
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Bots that do not destroy you, only make you stronger.

Dont forget you need the "BR" series Spektrum receivers for combat failsafe, unless they've changed the failsafe functions in the modular stuff ?
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

Hi all, long time no post, haven’t had much time lately but have been slowly making process on the tracked vehicle when possible.
Just tested it for first time on conveyer so thougtht to film its Frankenstein moment of meeting electricity.

http://www.youtube.com/watch?v=bksbHnxaARA&feature=channel_page

So far from the vid have learnt it travels at 5kph pretty much over most things with a load not yet determined but guessing at least 50 kilos+

On a separate topic good luck at the ideas festival everyone.
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Bots that do not destroy you, only make you stronger.

Looks nuts

Long time no speeky.
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Tim Team Reaper.

Just another vid,
driving it slow to test out the springs, a bit to do still but making sure everythings working OK before i start overvolting. Everything internally is just sitting on the floor so have to behave a little longer till I make the battery mounts and do the wiring etc.


http://www.youtube.com/watch?v=VvM7EbxjHVE&feature=channel_page
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Bots that do not destroy you, only make you stronger.

finally got time to make another vid yesterday, still at 12 volts, 45 kilos without batteries.

http://www.youtube.com/watch?v=Y5tfvQjeOFI
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Bots that do not destroy you, only make you stronger.

are you bringing it to robowars so us plebs can look at it

how was the chassis of it done btw. got me all curious now, looks like it was cut out from a flat sheet and folded to shape?

drive setup looks so awesome. so many moving parts close together. tis beautiful
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

RC Tank steer skateboard
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They say that he crossed the fine line, from insanity to genius.

Hey Glen, yes its bent, your powers of observation are outstanding.
Thanks for noticing the gearbox, forgot how much of a pain that was, especially doing it after the body. Thanks to Daniel Marshal for bending the body for me.

Heres a pic of the start of the transmission for next years tracked bot. Its 6mm plates clamped together with an internal profile to help drain the oil. I have moved into laser cutting a fair bit. Gearbox looks better with bearings and gears in place.

http://www.robowars.org/forum/album_pic.php?pic_id=1514
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Bots that do not destroy you, only make you stronger.