What the heck......

[DMCdesign]

been getting a lot of scientific mumbo jumbo into my head and thought to take a break and this is what I find.....

http://endless-sphere.com/forums/viewtopic.php?f=35&t=52820

what do you think about the drive?

 

[machinist@large]

been getting a lot of scientific mumbo jumbo into my head and thought to take a break and this is what I find.....

http://endless-sphere.com/forums/viewtopic.php?f=35&t=52820

what do you think about the drive?

I'm guessing you're referring to the apparently fixed shaft/ rotating motor casing design? Novel, but entirely doable.

I think I'm going to have to pass on the rest of the thread; after all I've lived thru along the way, taking up skateboarding is fighting it out with other things of it's type at the bottom of my potential new hobby list...

 

[itsid]

It's not that new.. I've seen RC plane motors like that somewhere,
advertised by "better cooling" and "easy airscrew mounting" or the like.
can't remember (isn't exactly my playground )
[EDIT]
Ahaaa.. they're called outrunners (for obvious reason)
here are some in a boat
http://www.youtube.com/watch?v=rZxFvoQsGvs

I like the concept though..
worth to think about reviving my old skateboard.

'sid

 

[machinist@large]

....worth to think about reviving my old skateboard.

'sid

Better you than me, my friend; it's -4* F outside tonight, and I'm in health insurance limbo right now....

 

[itsid]

Better you than me, my friend; it's -4* F outside tonight, and I'm in health insurance limbo right now....

-4°F ???
You have my sympathy.

we still reach about 54°F (12°C) each day and I'm freezing already.

Anyways, I don't have a motor like that at home.. neither do I have any possible battery pack or controller or anything laying around.
(or 400 USD for that matter )

But I like the idea, I think I want a motor on my kickboard rather than my skateboard, but something like this can be moved around

I'll see what I can find for cheap to try... maybe not as elegant of course.
And most likely not within the next two weeks

'sid

 

[DMCdesign]

Better you than me, my friend; it's -4* F outside tonight, and I'm in health insurance limbo right now....

-4* F is pretty less. We are having -4* C here and still no snow

The outrunners are pretty popular with EV builders. Here is one with a gigantic Turningy motor.

http://hackaday.com/2013/04/05/electric-tricycle-build-log-is-like-hacker-crack/

and sid, there are motors cheap enough to run that skateboard. If I remember right I saw on go for as less as 5-9 $

 

[itsid]

and sid, there are motors cheap enough to run that skateboard. If I remember right I saw on go for as less as 5-9 $

Well my first online stop (at a local electronics market with a good amount of RC parts) wasn't too promising.
the motors I looked at (1170W and 1250W) where 150 Eur and 200Eur (kickr's has 1100W), and the matching controller with cruise control and brake assistant are anywhere from 140Eur up to 300Eur. (100 Eur ~ 136 USD)
That's not gonna happen!

So I looked at some chinese products and found motors more in the 30USD range and controllers in the 50USD range.
that sounds more reasonable

But I already ran into a problem.
The motors are fast, generally about 1000 rpm per Volt or higher, most are stalling at 11Volts...
So slowest they go is 11000 rpm
with a diameter of about 50mm thats 1750 m/min or about 105km/h or 65mph ...
I know that wouldn't work, but if it would, that'll be scary on a skateboard
But at least it doesn't sound right,
since I cannot gear it down obviously

I need something in the 200-250 rpm/V range,
one that doesn't stall at only 4.8 Volts

I've seen one that I might be able to mess with on ebay (if it's cheap enough I'm going for it)

Next stop is a local Heli-RC shop about 10 km from here,
I need to have more info on the motors and controllers
before I'm going to spend any more serious amount of money.

Again RC stuff isn't exactly my playground, and I know close to nothing about the parts here.

I'll let you know.

Oh, and just in case any of you know a motor that'll match or a really cheap programmable controller with cruise control and brake assistant please let me know.

'sid

 

[DMCdesign]

here are 4 going off at 36$, 930 kv

 

[itsid]

here are 4 going off at 36$, 930 kv

Yeah still way too fast

But I'm sure there are motors that fit;
found a turnigy 168kv 2400W for example (too expensive to play around with it and too big to fit)
There should be something with a little less power and a little smaller that I could afford to ruin completely

I found a cheap motor with just 200kv but it's short and wide, too short to make good contact, too wide to fit onto a skateboard and even worse.. it's only in the 350W range.

So there will be some more research first
I think I'll hit the Heli-store on tuesday to ask for some infos.

'sid

 

[DMCdesign]

what would 1000w translate into volts?

 

[itsid]

what would 1000w translate into volts?

depends on the motor of course, but the powerrating is given for 22.4-29.6 most of the times (of the ones I've seen yet)

'sid

 

[itsid]

New day new post...

Back from the heli store, Thanks to a very helpful employee who spend 45min explaining things and browsing catalogues for me,
I now know just a tiny little bit more, and that's not too good.

So, he explained that those motors are either low volt OR low kv (rpm/volt)
not both, because they always need a minimum rpm to run properly (about 4500rpm)
because of the controllers made for rc stuff need to be small and lightweight ...
I couldn't even start listing the details, but after all it sounds plausible,
three phase motors require more than just constant voltage to run...

Well, I think now it makes sense that a kickr is expensive, the motors they use most likely be custom wound for that specific task.
And the controller will be at least reprogrammed from the ground up (if it's not custom tailored hardware)

The closest thing he was able to offer was a 120€ motor and a 150€ controller, neither of which I bought (too much money to just throw in the bin next week )

I will keep my eyes open, but I don't think I'll go knee deep into further research until I have proof of the existance of a matching motor (200rpm/volt @ 6Volts minimum voltage with at least 2000W max output)

'sid

 

[itsid]

third in a row... hmmmm

boosted boards http://www.kickstarter.com/projects/170315130/boosted-boards-the-worlds-lightest-electric-vehicl
one year older than kickr.. basically not too different project (although not as portable)

Anywhooo...

I got some good reads in the meantime (some 30 pages on instructables and a couple more on linked sources and blogs)

I think the Heli-shop-employee was WRONG!
There IS indeed a chance of getting a motor to do what I (we?) need here...
And it's much smaller than I was afraid it would be

keep your fingers crossed.

'sid

 

[DMCdesign]

Great!

I was having some problems with my computer, which are very hard to cope with.

After some time of use, the computer fades away, and after some struggle, it starts to lock the computer........