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Boostedboards.com says they use twin brushless motors, total 2000W

enter image description here

Anybody know what they are? where I could get a couple? Guesses or pointers welcome, I'm not really familiar with small electric motors.

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    \$\begingroup\$ Brushless DC motors have stator windings and a permanent magnet rotor with commutation provided electronically. The picture you posted clearly shows rotor windings, making this very likely to be a Brush DC motor, marketing claims notwithstanding. \$\endgroup\$ – HikeOnPast Oct 31 '12 at 16:27
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    \$\begingroup\$ @DeanB - Sorry, but you're wrong. The motor in the picture is what's called an "outrunner" brushless motor. It's basically what it sounds like. The windings are on the inside, and are held steady. The magnets are attached to the can, and the whole can rotates. \$\endgroup\$ – Connor Wolf Nov 2 '12 at 8:02
  • \$\begingroup\$ See my answer for an example of this type of motor. \$\endgroup\$ – Connor Wolf Nov 2 '12 at 8:02
  • \$\begingroup\$ @FakeName, I've integrated that type of motor into several pieces of equipment in the past, so I'm pretty familiar with them. We're way out into speculation land here, :) , but the fact that the motor in the picture has a substantial shaft diameter and what appear to be relatively thin webs from the can OD to the shaft seem highly inconsistent with at least my experience working with "outrunner" or "inside out" BLDC motors. I'm open to being proven wrong, though -- you learn something new every day. \$\endgroup\$ – HikeOnPast Nov 2 '12 at 15:53
  • \$\begingroup\$ Thanks to you both, Seems my answer is to get my hands on several and figure out what may actually work. \$\endgroup\$ – Issac Kelly Nov 2 '12 at 16:00
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It's hard to say what are the specs, but speculating on the size of the battery pack, it's probably a 14.8V lipo battery pack. P = V * A, P=2KWm , 2 motors therefore P=1KW -> 1KW/14.8 =~67A. This is a relatively high performance brushless motor setup and it is not surprising, given the mass it is supposed to be moving (180lbs is a good guess for a human).

I bet their motor setup is custom designed to maximize efficiency so you won't find on the market the specific motors they are using. All that said, if you plan to do something similar, go with Scorpion Systems motors, designed in Germany and manufactured in Hong Kong, which are really good motors. You will need two motor speed controllers (ESC) and a way to generate a PMW signal as input to the ESC so to control the motor speed. See the specs of the speed controllers. Typically hobbyists use these motors for radio controlled devices .. so you can use a cheap transmitter/receiver setup, cost like $30 these days.

http://www.scorpionsystem.com/ ... you find distributors all over the web. These are not cheap motors ... there are cheaper brands. Check HobbyKing.com Look for 14.8V (or 4 cells) motors. You'll need to find a motor with a Kv (number of revolutions per 1V of applied voltage) such that you get the required power at the desired spin rate of the motor , which depends on how fast you want the wheels to spin ... Ultimately what defines the power demand on the motor is the load .. and this is where this boostedboards guys are doing the hard part ... there is almost no way to limit the load ... the user does not know how much power he/she is demanding, because it depends on how fast the wheels spin and how steep the road is. These guys are probably designing a speed controller smart enough to self control .. when Amps goes too high, it will likely reduce voltage before burning the entire system, which can happen quite fast.

It is an interesting idea and project... even though I wouldn't put my feet on an electric skate board ;-)

Please note that they use the electric motors as dynamic brakes. Standard ESCs available on the market won't let you do that ... not sure if there is such thing as an ESCs able to use the motor as dynamic brakes.

Hope this helps. Regards

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  • \$\begingroup\$ Thank you very much. It definitely helps. I plan on writing the controller and the other electronics myself, it's just a hobby project. I'm almost certain that they're buying something off-the-shelf (for now) for the motors. Everything else I've been looking at also suggests that the best size/power ratio is in hobby motors right now. \$\endgroup\$ – Issac Kelly Oct 31 '12 at 15:47
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You want www.hobbyking.com

They're the largest of the "Stupidly-cheap-chineese-import" retailers at the moment.

They have brushless motors up to 10 KW! enter image description here

For reference, the above motor is the size of a can of beans.

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with regards to the debate whether these are brushless or else motors ... if you check the website of the company .. ( check the video and the company website ), they speak of " advantages of brusheless motors if you can design the ESC ... ". Hope that settles it. This said .. in the end, you can do all you want, you can use any kind of motor, but there is a huge advantage with the brushless motors, which is that the ESC is purely software. SO, you have the freedom of your mind in the design process. Also brushless are lighter, that's why they are very often used of RC airplanes ... weight to power ratio is critical

Moreover.. and that's the real gem: Scorpion Systema sell brushless motor kits .. in other words, you buy the hardware then do the windings yourself by hand ... you can get any configuration you want and tightly target your design specs. Total freedom .. which I am sure will lead to fiery results at beginning .. all amazing endeavors pass through rough times ;-)

I am not smart enough to design an ESC .. and have two kids 2 and 4 who take some of my time away ;-) However, the idea of an ESC that can also use the motors as dynamic brakes, recharging the battery in the process (which of course adds the problem of controlling the battery charge - Lipo battery will burn very quickly if over charged) is something I would be very much interested to read, if you were willing to publish your work, while you are doing it. Of course, you don't have to .. all I am saying is that if you do, you'd have at least one follower ;-) Good luck

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  • \$\begingroup\$ If I do it, I'll definitely be publishing. I'm hoping for a lot of learning. I still have all the tabs open to start purchasing parts. \$\endgroup\$ – Issac Kelly Nov 7 '12 at 3:15

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