Anybody know a ton about electric motors?

[Aerosol]

Cause I could use some real...basic info I guess.

which manufacturer should I turn to for some ridiculously powerful brushless outrunner motors? say....motors that could easily propel something weighing upwards of oh...45 pounds. It's hard finding info myself, cause there's no one site that has an active forum for me to ask questions on. I was originally going to build the motor myself (cause I'm almost positive no manufacturer makes a motor with the kind of power I'm after anyway), but I found even LESS information on that. so yea.

[cyborg_ar]

look at these

http://www.rctoys.com/rc-products-catalog/RC-PARTS-BRUSHLESS-MOTORS-HACKER.html

[Smidge204]

I guess the obvious question is... what's it for? Can't really select a motor unless you know it's application.

"Propelling 45 pounds" - at what speed? Does it have to be a brushless DC outrunner type? etc etc

=Smidge=

[Aerosol]

I don't like telling people what the application is cause most people either go "never gonna happen" or "you've got alot of work on your hands!". That doesn't help me much.

Basically, in a nutshell, powered rollerblades.

oh, and 15-20mph smidge. That 45 pounds is 180 pounds split between 4 wheels, 2 on each skate.

[Epon]

... that's a decent amount of torque needed. Hope you have lots of money. Why not gas?

[Aerosol]

Yea, I know gas would be easier, but it's been done already. They're ugly as sin though, and heavy as hell. Plus I'm a hippy.

I know of two ways to increase the torque. One way is to mount the motors directly onto the wheels. The other way is to pump as much current as possible into the motors. Thing is, you have to build the motors a certain way to do that.

[wesker]

Sounds like fun, I know it doesn't help but let me know when they're done so I can give them a go :X

[Smidge204]

Okay, you probably DON'T want outrunner motors.

Not sure what your budget is, but I'd suggest something along the lines of cheap cordless power tools. Optionally carry an inverter as well and use (much cheaper) AC motors but less bulk is always good. Garage sales and swap meets are almost always a good place to find cheap, used power tools. You can also hit up eBay.

I would recommend adding a fifth traction wheel, rather than trying to modify the existing wheels in any way. That will save you from trying to re-engineer all the bearings. Also, a fifth wheel could be retracted/removed in case your batteries go dead - then you'd at least have normal skates again.

First thought was using an angle grinder. The motor is mounted perpendicular to the output shaft, meaning you could mount the thing to the side of the skate and a traction wheel directly to the shaft. Cordless grinders start around $60 and go up as much as $500 though.

Anyway, electric skates have been done before too My $.02.

=Smidge=

[DimensionWarped]

For some reason I'm thinking of spray paint propulsion. Ok. I'll stop now.

[ila]

I don't recall motor blades in Jet Grind Radio.

[hRook]

This is a truly incredible idea.

[Aerosol]

Angle grinder skates have also been done already. The only motorized skates I know about aren't really interesting at all. You mentioned the mounting on the side though, smidge. I thought that maybe, instead of mounting the motor directly inside the wheel, I could mount it on the side of the frame, and power the wheel that way. The only problem with that is a loss of torque, but that may end up being not so much of an issue.

[Smidge204]

You wouldn't lose torque. What you would lose is the bearing on the wheel - which means you need to make a new one.

I think I understand why you wanted an outrunner motor... using the motor's external rotor as the wheel itself? I can tell you flat out that is doomed to failure.

What you want to do (drive the existing wheels directly) is certainly possible but there's a reason nobody's tried that before - it's a bitch and requires modifying the the entire skate. You're almost better off starting from scratch.

Here's one idea, though. Widen the bracket the wheels fit into to allow you to attach a spur gear to the face of the wheel while letting the shaft pass through without contract. You might then be able to drive the wheel using a mating spur gear. If you want to drive all the wheels you can insert idler gears between them.

=Smidge=

[Epon]

If you were a real hippy, you'd stick to foot power

[DimensionWarped]

I don't recall motor blades in Jet Grind Radio.

The idea just kind of chimed thoughts of Jet Grind Radio in my head...

[Aerosol]

My idea with the outrunner motor wasn't so much using the outside of the motor as the wheel, but mounting the motor inside an outer wheel in place of an inner wheel.

Also, if I were going to do it that way, wouldn't it be more effective to use chains? Kind of like a miniature electric motorbike of sorts.

[Damizean]

Basically, in a nutshell, powered rollerblades.

Too much Airgear, huh, Aerosol?

[Smidge204]

My idea with the outrunner motor wasn't so much using the outside of the motor as the wheel, but mounting the motor inside an outer wheel in place of an inner wheel.

That's functionally the same thing...

Also, if I were going to do it that way, wouldn't it be more effective to use chains? Kind of like a miniature electric motorbike of sorts.

Not really. You'd need really small chain, since chains don't work too good on sprockets with small numbers of teeth. Chains are subject to "chordal action" because the effective radius of contact changes, causing speed fluctuations and vibration. All chains do this, but it's not a problem if the sprockets are large enough... but how big is a skate wheel? 3 inches, tops?

Find a high speed motor with a gear box on it. At 15 MPH a 3" wheel will only be doing 850 RPM so that's easily doable with plenty of torque if you have a 10K RPM motor or something. I still think power tools are your best bet for motors. {Edit:} A cheap cordless drill ($20-40) would be perfect, actually. High torque motor with a pistol-grip throttle control and standardized, rechargeable battery packs.

=Smidge=

[Aerosol]

well i wanted to do something like this before airgear, but airgear spurred serious thought : p

@Smidge: actually, the wheels would probably be a bit larger than that. Between 4 and 5 inches. So even less rpm! Also, what I meant to imply with what I said about the motor being mounted onto the inner wheel as opposed to the outer wheel was that, by mounting it onto the wheel, there is that extra layer of shock absorption. Also, if you can find a small power tool that I can tinker with, then im all ears. So far ive only really considered the dc motor route.