High power RC motor and drive unit production

[MitchJi]

Yeah, this is all coming together pretty nicely. The motor I'm building will be "capable" of very high peak power levels somewhere north of 15Kw if it is geared correctly and run at high voltages. The problem is that the current controllers will not limit power when temps get out of hand. This is something I really worry about if Joe the plumber buys one of these. Riding hard in the mountains pulling 9Kw continuous would heat things up a lot...and ruin the motor. We need some sort of circuit to measure controller/motor temps and start beeping like mad and limit the throttle when temps get out of hand. This should be an easy project for anyone with a bit of programming skills

Hi David,

I'd be more worried if Sarah Palin buys one (Sorry I couldn't resist).

The Eagle Tree Logger has provisions for adding temperature sensors. I don't know if it has any provision for outputting a signal that can be used to limit the throttle.

I don't need the very high power. What I want is something that is bullet proof and efficient in the range of about 2kW to 3kW sustained (hill climbing). I also don't want to run at over 36v or 48v. I want a system that is safe and reliable in the rain. That means I am going to do everything I reasonably can to make all of the electronics waterproof. But in case there is a problem I don't want to be riding an 85v system with a short circuit.

This raises a question. Will your motor or one of your motors (if you have multiple 60 series models) operate efficiently at 36v or 48v?

And a suggestion. I would do everything that you conveniently can do to encourage purchasers and make it easy for purchasers to assemble and install a system that is safe in the rain.

I also have a question for Matt. What is the approximate range of reductions that will be available with your two stage drive unit?

[recumpence]

Oh, man, almost anything is possible with a dual stage reduction.

Hmm, let's see, the primary belt drive could be as low as 6 to 1. Then the secondary drive could go as low as 4 to 1 if we really wanted to. So, that is 24 to 1 just in the drive unit, not including the final drive to the wheel.

Basically, the secondary drive will most likely be .25 chain drive just like my recumbent. That reduction could be anything from 1.1 to 1 up to about 5 to 1. I will probably make the prototype roughly 2 or 3 to 1 at teh secondary chain drive, and 4 or 5 to one for the primary belt reduction.

Matt

[CNCAddict]

This raises a question. Will your motor or one of your motors (if you have multiple 60 series models) operate efficiently at 36v or 48v?

And a suggestion. I would do everything that you conveniently can do to encourage purchasers and make it easy for purchasers to assemble and install a system that is safe in the rain.

Yeah, the motors will work great at lower voltages. They'll just spin slower Also, I plan on getting things as corrosion proof as possible on the motor. Electrically, brushless motors can run underwater. It's just the corrosion that's a problem.

[etard]

Yes a sketch please! Fingerpaint, crayons, whatever. I need to know how it can all be done on one shaft. I'm losing sleep over this. Oh yeah, can mine have lasers on it? Hehe
These are exciting times, everything is moving so fast now. I hope you guys are going through the necessary steps to protect yourself, in case any chinese manufacturers are watching this.

[recumpence]

It is truely an exciting time!

Ultimately what I would love is a light weight, but robust, E-motorcycle for all around use and an E-bike for around town bashing.

This new motor and a decent drive will definately move us closer to that goal (as will the new Castle controllers).

Now what we need is safe lithium batteries in the .20 per watt-hour price range.

Matt

[recumpence]

We (David and I) are working out the details of the first prototype motor. I am funding the first for my own testing.

It looks like we will be going with a very large diameter shaft (12mm) to start with (15mm through the bearings of the motor for better bell support). Also, I am having him tap the face plate of the motor to use two screws side-by-side per side so the pulling force on the belt will not scoot the motor in the mount.

I am excited to see this. David and I are both working hard on finalizing the details of the motor and the drive. I am making every provision I can for the drive to work with his motor and he is making every effort and provision for his motor to run well for bike use and with my drive.

The prototype motor will be 200KV. That is pretty much ideal for testing.

I am hopful that I can test the new motor before the snow flies! The new drive will be ready by then, but I will not be able to test it on a bike at that point because it would be very difficult to retrofit my recumbent and my mountain bike will not be ready by that time. I will run the motor in my existing recumbent drive, though. The production, modular reduction unit will use proven components that I am running on my recumbent (15mm wide primary belt to .25 secondary chain). That system is good for 5,000 watts minimum continuous. I have seen over 7,000 burst through it.

Matt

[deecanio]

Hi All,

Great to see all the RC info having it's own area, makes keeping up all the easier and boy is this tech moving fast.
As you all know im also looking for a new drive system for my kona, has to be fast, has to be light, has to be robust, basically RC setup capable of taking the kind of punishment shown in the video from the recent meet.
Same as all the other DH guys (we're a growing crowd don't you know) i am looking to Matt and David to produce something special here and im pretty confident that they will

a few questions though............

will the motor be controlled with the RC esc/servo approach ? weight of motor? availability date?
it seems that the motor will have some spanking specs, but if it takes fairly high voltage will the performance for say 36v users be ok? can it be geared accordingly? half of the appeal of the rc stuff for me is runing at lower voltage.

Matt,David,

i have a test bike here and good to go if you want to test the robustness of the build no problem
If you need an R&D fee let me know and we could work something out

exciting times indeed ~

Cheers,

D

[johnrobholmes]

Mind if I hop in here with my designs Matt?

[recumpence]

Mind if I hop in here with my designs Matt?

This forum doesn't belong to me. Feel Free!

Matt

[johnrobholmes]

You started this thread about your developments. When I get more news on mine I will add in my developments then. So far my machinist is "behind". He can make 400 pinions for me in 2 weeks, but can't cut 4 gearboxes in 3 months

[recumpence]

That's cool.

If you want to shoot me some of your design specs, I can get them to Dave. He is short of work right now. I am not sure if the price will be the same. But, if it is, he can whip stuff out quickly assuming his work load is still low.

Matt

[johnrobholmes]

As long as he can cut modulus 1 gears it is all good. I have diagrams but no cad files right now.

[CNCAddict]

As long as he can cut modulus 1 gears it is all good.

Haha, you wish. Sadly my gear making abilities suck. It takes some major fancy equipment to do custom gears. HTD pulleys I can probably pull off, but anything with a sharp inside corner is a bit impossible with my current set of machinery

[etard]

I think alot of us are going to put this system on DH bikes, so my concern is what to do about a rear brake. Looking at my bike, if the drive unit where to feed from the top of the rear tire to a gear on the rear disk mount, it could be possible to have a disc caliper between the chain, inside the drive. What I am proposing is that the gear and the braking could be done on the same piece of metal. However, oil and brakes do not seem to be an ideal combination, if you used a belt and made a custom brake caliper that left room for a fairly wide belt on the inside, this could be done and still be bolt on to original brake mount without frame modification. (breath in)
Matt,
Is it possible to use belt drive for final drive? Or could I use a chain wax instead of grease and just add teeth to my disk brake caliper?

CNCAddict,
Do you think you could machine a custom brake caliper that fits around a belt drive sprocket?

The way I see it, is if everybody contributes something, the end product could be available sooner. Oh by the way, I have access to a waterjet (is that what its called?) if that would help to make custom sprockets, gears, calipers, etc...

[recumpence]

Too funny!

The Dave is was referring to is Dave Monsen the owner of the machineshop my shop is located in.

The project I was talking about is the box itself, not the gears.

Man, that is a good example of talking right past each other!

I'm at the shop working on the CNC programming for my drive unit tomorrow afternoon!

Matt

[recumpence]

I think alot of us are going to put this system on DH bikes, so my concern is what to do about a rear brake. Looking at my bike, if the drive unit where to feed from the top of the rear tire to a gear on the rear disk mount, it could be possible to have a disc caliper between the chain, inside the drive. What I am proposing is that the gear and the braking could be done on the same piece of metal. However, oil and brakes do not seem to be an ideal combination, if you used a belt and made a custom brake caliper that left room for a fairly wide belt on the inside, this could be done and still be bolt on to original brake mount without frame modification. (breath in)
Matt,
Is it possible to use belt drive for final drive? Or could I use a chain wax instead of grease and just add teeth to my disk brake caliper?

CNCAddict,
Do you think you could machine a custom brake caliper that fits around a belt drive sprocket?

The way I see it, is if everybody contributes something, the end product could be available sooner. Oh by the way, I have access to a waterjet (is that what its called?) if that would help to make custom sprockets, gears, calipers, etc...

One of the best solutions would, indeed, be a Sproder (sprocket/rotor). The chain lube is not a huge concern for them. There are non-greasy lubes out there. Also, it is possible to get a sprocket and a rotor side-by-side in that area.

I am going with chain final drive. I may move to belt on my recumbent at some point. But, for width concerns with a rear brake, chain is best.

Of course, there is also the option of a small disc on the output shaft of the reduction unit. I just want to get the reduction done first.

Matt

E-tard, I live the avatar pic. I am watching the Aptera with great interest. Heck, I am looking at building a "Neighborhood Electric" slightly oversized tadpole trike. It would basically be a full suspension version of a typical pedalled trike with double wishbone front suspension and a much wider front end for stability, no pedals, and a steering "Wheel" like a Cessna yoke that uses mostly (or all) hand controls. I am looking into the laws regarding this right now.

[CNCAddict]

Haha, yeah I guess I'll officially be CNCaddict here and not Dave, lol. Anywho, I personally am going to stick a gates carbon 12mm on my bike to see how it goes. These belts are ridiculously strong, but I only have a reinforced plastic pulley right now borrowed from the ixi bike. It is designed for the poly chain belt, but I worry it will explode when I put over 100ftlbs of torque on it. Anyway, I got 3 8mm polychain pulleys for $125 with some haggling which isn't too bad. You can check them out here. http://www.ixibike.com/

More belt fun http://www.youtube.com/watch?v=FHMChA0M ... re=related

[deecanio]

I'll be going with belt drive too, it may need a little more space to run alongside a disk but i think fitting won't be a problem especially if you can gear so that the pulley is smaller than the rotor.
Good to hear your on the case guys - realistically when do you think we will see the motor CNCaddict?
I'm basically hanging on to see what you guys come up with but if its a way off i may try off the shelf first.

Cheers,

D

[recumpence]

The only reason I am not running a belt final drive right now is drag. Under power, a toothed belt is very low drag. But, when a large pulley spins a small pulley in a freewheeling condition, there is a bit of drag present. I like to pedal without any discernable drag. Also, a chain final drive is basically silent as long as the small sprocket is not spinning to fast.

I am at the shop tomorrow afternoon CNC programming for the reduction drive. However, I am stuck waiting on some mechanical tubing to arrive before I can start machining.

Matt

[deecanio]

Hi Matt,

thanks for the info, maybe i should reconsider chain drive, i had ruled it out due to noise, mmmmmm.
looking forward to seeing what you come up with and more so what your going to do with that mean dh

Cheers<

D

[recumpence]

I am not trying to sway you on your final drive choice. However, again, if sprocket RPM is kept low enough, noise is not an issue.

I cannot hear the chain on my recumbent at all.

Matt

[CNCAddict]

Yeah, the belt vs. chain decision is really preference. For a high powered setup where no pedaling is done, I would take the belt because there is no maintenance, belts are cleaner, and the slight decrease in efficiency shouldn't really matter.

The motor will be done at earliest in a month. I have to order all the parts first (not quite done with the design). Then it takes a while for the magnets and stator to be made up and sent to me. The other parts I can make really quick since I've got the CNC lathe and milling machine here at the house. If you know a fast/affordable way to have custom magnets made up..please let me know

[deecanio]

Hi Guys,


i wish i did know a fast way for custom parts CNC, i might be a bit closer to finished than "just needs a drive"
belt vs chain is tricky (don't worry matt, no swaying felt), chain is much easier to mount but imo belt is a slicker look,but i dont want any drag (with all belt drives?) , anyway i guess it doesn't really matter as long as it hauls ass whilst not blowing my stealth, something i had no problem keeping with my hub.
i think i might try something in the interim as long as its not too expensive, did either of you look at the magmotor and box i posted? Miles mentioned that it wasnt very good for efficiency but other than that no one commented? i would like to know what you think of that in particular matt and eplain its shortcomings.
i Think my problem is i need to bone up a bit on motors and gearing, i could look at 100 motors online but not understanding their specs how would i choose one?
Anyway enough of my bleating, crack on gents, you guys rock


Cheers

D

[MitchJi]

Hi Guys,

i think i might try something in the interim as long as its not too expensive, did either of you look at the magmotor and box i posted? Miles mentioned that it wasnt very good for efficiency but other than that no one commented? i would like to know what you think of that in particular matt and explain its shortcomings.

Cheers

D

Hi D,

It sounds like one of Matt's 2 stage might be ready fairly soon.

You might want to consider using that drive with an interim motor. That might be easier than building your own gear box and when you build your more permanent system you would only need to mount a new motor on your existing box plus maybe change a sprocket or two to tweak the drive ratios.

[etard]

Sproder, huh... Now your making things up Matt. Haha

The cessna yoke sounds like something I was contemplating. So what, you pull back to go faster and push foward to brake. That would add a whole new experience to those trikes. What if you rigged the seat to sit up a lil when you push foward, and swing back (better aerodynamics) when you pull back on the stick.

I was joking with one of my friends as I was explaining the RC application on bikes, I told him I'm going full fly-by-wire. I'm just gonna get the rc car wheel controller to steer, gas, and brake. But, it got me thinking, and I think on a tadpole, or trike you could actually do that, if you had the right servos.

CNC,
There are alot of guys that build thier own motors on the forum : http://www.rcgroup.com. Those guys special order magnets and windings, etc... all the time. I would be willing to pay more for better magnets though.