#crossbreaks' midmotor CB120

I've been wanting to try similar to the bht, but havent because it's not easy to add a protected fan to the outside of the motor. Open blades/props aren't good, and mud/dirt is as much a consideration whether can is open or closed.
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I mean that any forced cooling, whether motor is vented or not should be carefully designed with mud/dirt in mind, and safety. I don't want an exposed metal blade driven by the motor it's cooling, to get tangled or cut stuff up, especially between my feet. I assumed the pro w/ ventilator would be already designed somewhat with those things in mind, but perhaps not if they were just thinking of planes.

I also assumed it wasn't a big deal to run (as the pro does) with venting and cooling. Alot of guys with hubs do it, and as long as halls and windings are varnished/protected the bearings seem to be the only other worry.

On an RV, much more adequate bearings (as you proposed) are very key whether sealed or vented. I am merely trying to offer/think further about the cooling. Outrunners are like hubs in that they are more sensitive to the heat they generate, due to disconnection in thermal mass, right? I can see how statorade should improve that and in combo with the .35 lams I agree the capability of the 120es should be between reg and pro120.

So you don't think the ventilated version would be a wise decision off the bat, because any potential cooling gains won't be worth the hassle of addled wear on bearings/seals and motor internals.

It's true since the can is already spinning a heatsink and as much extra surface area for a little turbulence is a great cooling idea they would have never applied because of the initial application of these. For us, maybe that + sealed and statorade will be the best combo of performance/power/longevity for bikes and offroad.

Should we ask RV about surface/exterior mods or plan on customizing ourselves for each application? I'm not sure exactly what snowy's suggestion would even look like actually.

Thanks for the discussion/ hashing out details!
 
Maybe snowy could elaborate a little about the cooling. I didn't get what he said either.
I get that all choices made will impact final price, but that also kind of make it tough to think of what is of most importance for most of the buyers.
Could sealed can with statorade work well with cooling fins around the magnets back iron? Would any sort of heat sinks on side covers contribute? I know we had a lengthy discussion just on that topic a while back in different thread, but frankly I can't remember if we ever got a conclusion about the side covers. I do remember some said surface area was too small to really matter because side covers was too far from heat source, maybe that was the conclusion? The rat in my head is moving slowly today. Summer hit hard yesterday. From winter to tropical overnight. 8)

I guess statorade with cooling fins/heat sink mounted on the back iron would sit close to the heat source and the statorade would minimize air gap hence better heat transfer.
Would it make sense to look into added cost for something like that added to ES addition?

There was some mentioning about varnishing the internal, seems best practice is to do that. Is that something worth getting ready made from factory? I mean we already pay extra for a better motor, could motor be made "fully modded and ready to ride"? Just attach motor to bike and hook up cables?

I don't know about you guys, I sure find all those little things to be a hassle, or maybe not as much a hassle as time consuming in a hectic every day life. I finished a QS 205 with varnish and flat black paint inside, sealed and closed her up and remembered I forgot to order statorade. Opened her up again, filled her up, sealed her up and closed her up. Then Artur went and did an axle mod, luckily he didn't have any spare axles :lol: ..........or it would have be another re run.

It would feel damn good to get all needed modifications done to order, for that I would put down some extra cash. I mean if we are going to do cooling mods ourself, add varnish, make custom heat fins etc that might end up costing more money then having it all done from factory? And lets not forget the the time spend kicking and screaming while something breaks while modding, or the final bolt snaps. You know those little things that seems to make things take so much more time then we first intended.
 
I like the idea of sealed like bht (tho bht does not have gaskets or shaft seal for statorade or water ingress), and the rotation of the can will automatically help cooling. I'm thinking rounded ridges running side to side to not only add a little rigidity but to 'catch' the air and thus shed heat better. Fins would really drag on the air depending on how they're oriented, and even though I bet we could really get some cooling from fins, I don't think we want a big spinning fan between our feet.

In a sealed motor I'm not sure at all what real benefit there is to extra varnishing/ coatings (unless we need to for the statorade?), and thought I remember the flat paint actually transferring convective heat (no light) ever so slightly worse than bare metal?
 
nutspecial said:
I like the idea of sealed like bht (tho bht does not have gaskets or shaft seal for statorade or water ingress), and the rotation of the can will automatically help cooling. I'm thinking rounded ridges running side to side to not only add a little rigidity but to 'catch' the air and thus shed heat better. Fins would really drag on the air depending on how they're oriented, and even though I bet we could really get some cooling from fins, I don't think we want a big spinning fan between our feet.

In a sealed motor I'm not sure at all what real benefit there is to extra varnishing/ coatings (unless we need to for the statorade?), and thought I remember the flat paint actually transferring convective heat (no light) ever so slightly worse than bare metal?
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From a safety aspect I can see that, but solvable? Probably. First thought come to mind is to cut some 5" tube strips and place a mash the length of the motor around it. A little wider then the motor in the total should prevent fingers and toes from getting hurt.

I've been toying with an idea to make a clamp on heat sink with heat pipes for the QS 205 and place it on the back iron. Safety wise no problem for a hub. Might end up looking a little odd or even fugly on a hub though.

But even for mid motor the idea of this style of added thermal mass with large massive surface is attractive. The AFT cooling comes to mind to use a a visual aid. Something similar would be very effective for cooling. If motor can go up on/under swing arm it would be less to worry about and would get a perfect chain line without any stress from movement of swing arm.

d49nlyQ.jpg
 
axle is down to 12mm, still fastened by an M8 bolt on the drive side
bearing is 6301, better load rating C0 = ~4kN (12x37x12mm)
sprocket is #35, down to 13T (from 15T)
sprocket support is thicker
wire side axle is now 30mm (from 25mm) and has 4pcs M6 bolts (V1 had M5 bolts)
phase wires are 6mm (were 5mm), shall fit AWG6 with insulation
wire side bearing is a 6906, better load rating C0=~5kN (30x47x9mm)

over all dimensions stayed the same
 

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fans blades would indeed be nice. after adding them, the rotor should be balanced again on a balancing machine. too expensive for me. I'm happy with statorade and some finish on the stator..the stator should be cast in resin like justin does :) sure a lot of work, i will ask if this can be done in factory but i doubt that
 

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Very nice expanded and improved mods and impressive calcs! That's about the reduction/voltage I'd shoot for and looks like torque will be ridiculous hehehe!

I will look into doing resin on/to stator in case factory doesn't. Also, if they wouldn't be bothered with some sort of fins/ridges/heat sinks etc, I guess it would be up to us.
I was actually thinking more of ridges or 1/2x 1/2" channel stock running end to end and evenly spaced around the can. It would look more like a paddlewheel than a shredder. What do you think?

What are the cans' exterior made of? Regardless who adds/adapts cooling material, I assume it would be most reasonable to mechanically attach instead of forging into or welding to the can.

Hopefully it's obvious since I've been sticking around I am tenatively behind you and the group order. We just need a few more. OR maybe RV can actually do more of a developer 'promotion' to us and we can each buy more than one. Your version should end up being highly useful and desirable crossbreak -very exciting!

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Also, I'm wondering what type of build you others are planning with this?

I have a feeling my dual FW is not going to be worth a try @ this power. . . What's the plan if you wanna keep working pedals on the build?
I am thinking of going n/a for a strict dirt build anyway, but one thing we're still missing is something similar a gasser's gear/clutch system to select motor braking or coasting. So far a FW works fine for me, but I don't know one that is likely to hold up to 15kw peaks :?: Guessing you guys are thinking of a direct connect?
 
Hello Crossbreak,

I don't think the non chain side needs a bearing with high load rating. Also, you need to use the dynamic load rating to do the calculations.
If you want I can help with the bearing calc.

I believe the non bearing side can be optimized for easier cable exit.

Let me know if you want help from me.

Roel
 
Rouckie said:
Also, you need to use the dynamic load rating to do the calculations. If you want I can help with the bearing calc.
Click to expand...
yeah, sure dynamic load rating "C". Anyway, max bearing load shall not exceed C0 from what i learned. This looks good for the 6301 but not so good for the two stock 61802 (where C0 equals calced load :oops: ). C is ~10kN for the 6301.

This is what i input: torque is always near maximum: 40Nm, this means a chain force of ~2 kN. I did not calc exact bearing loads, just assume that the drive side one (6301) will fail first and carry just the chain load (in fact this is a bit more, but it wont be always be at maximum all the time).

L10 = (C/P)^3 *10^6, (with P = load)
L10 = (10kN/2kN)^3 *10^6= 125 million revolutions.
with one revolution being 0.45 m at the wheel (reduction of 4.7 and tire circumference of 2100mm, which is a 26")
= 125 million * 0.45m = 56 250 km or 35 000 miles for the chosen 6301 bearing. For the two stock 61802 (C0=1.9kN) that would be 3086km or 1920 miles if they would share load equally (which i doubt).

think this is realistic and appropriately simple. yes? How to calc bearing life of the wire side? No idea...could calc it by assuming some unbalance of the can though... but how much?

Rouckie said:
I don't think the non chain side needs a bearing with high load rating.
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the only smaller bearing i see for the wire side is a 618006 which is just little smaller (7mm vs 9mm of the 619006), but carries much less. Friction torque isnt lower either. So i chose the more robust one here as i dont know the unbalance of the can, but yes this one still has lower dynamic rating than the drive side one, it is C= 7 kN.
 
chain lifetime of the #35 with 13t front sprocket and 60t rear

chain velocity at 2800rpm is:
sprocket circumference: 0.0197m *2pi = 0.124m
speed is 2800rpm *0.124m = 347 m/minute or 5.8 m/s

links: axle distance to is ~ 0.4 m (closest possible with a 26" tire), so about 2*0.4m / 9.575mm = 84 links, add another 30 for the rear sprocket and 6 for the front one: 120 links (weight: 471g)

I calced 2.2kN dynamic chain load with a calc tool i found somewhere. No surprise here as chain speed is medium. i can't find a tool that allows me to calc chain life time. Anyone?

DID states 3.7kW for the 13t #35 here: http://www.did-coltd.com/english/products/pdf/sr_35.pdf
this is only 14 Nm at the motor :?
they also state that max allowable chain load is 2.15 kN which is very close to what i calced at 40Nm. Seems like the #35 with 13t is more on the weaker side but still doable. Maybe go back to 14T again...or let people decide whether they want a chain that lasts forever or a smaller cog on the wheel. I see this 13T #35 more like a "suggestion". People can use what ever sprocket they want as long as it's dia is as least the dia of a 13T #35 (or flanged #219 sprocket that can be as small as 10T). With a 60T #35 sprocket on the wheel, it doesn look that bad. A 60t is 180mm in dia, still smaller than the 203mm brake disc on the other side.
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Now we just need a frame with swing arm/pivot point/bb something like this and it will be all OK.

The rendering is the work of myosis
 
Your calcs look good crossbreak. I'm interested in the mention of improved wire penetrations?

I would feel comfortable with #35 down to the 13t front. If it wears too fast it's time to upgrade chain or up tooth counts I guess. From what I remember, 2500-3k rpm on 13t is about as fast/small as you wanna go with #35, while the chains have generic tensile strength of about 3/4 ton- better for this torque than 219.
https://en.wikipedia.org/wiki/Roller_chain
http://www.tsracing.com/Techtips/TSchain.html

I read myosis's thread also, and agree the urt design will be far more practical, simple, durable, etc. Perhaps some would prefer jackshaft, but I know I'm not messing with making one.

Part of the idea of 120es is width to fit on a narrow platform with the ability to use standard crank tread, but how do we plan on delivering the power in tandem with pedals? Either jackshaft or parallel chains. . .
I might even go pedalless but would still like a freewheel. So maybe just a little motor application talk/ links could be good and would even aid more attention/interest in 120es and groupbuy, as not many people likely have an idea how to apply it. If that's too much/ you disagree crossbreak, I also submit since you're the thread author.

Macribs, consider the raptor frame or this 'copy' I will be using. Easily modded steel, with room under swingarm for motor mounting. https://endless-sphere.com/forums/viewtopic.php?f=3&t=70616&hilit=denzel&start=50
 
My kid is 4 year old and he has very highly modified oset 12.5/16.0 racing hybrid. We use it on trails, Enduro, trial and motocross so we need power on everything else but trials.

Our swing is 130mm wide and 130mm length (if we add 30mm to rear swing) In that space we should put motor, axle and motor mounts. We could put Rv120 could be tight fit and easy to put on but would the power be enough? RV-120 could fit if rear axle removed. Total weight of the driver + bike and batteries is around 40-42kg, so very light. What would you guys recommend?

Now we use stock xyd-13 motor (500w) @ 2000 watts, but it's effiency at that power is only 55%.

IMG_20160607_150527.jpg

takajousi_1.jpg

Don't mind the texts on swing image, they are not relevant.

This is modified RV-120 they can provide to me:
image.png
 
look perfectly suited for en RV120custom. Very nice swing arm. You just have to figure out how to mount the shock on the swing arm. That might be the hardest part.

I think if you have 500W continuous and go 4000W continuous, power will be plenty... it's a 700% improvement :twisted:

i would not try the stock RV120, as bearings are not big enough for these high radial loads, a main reason for the redesign. Also the lams are crab on that RV120-nonpro

we still need more users who are definitely in - too many "maybes" to gives this a go. there is no good motor out there that's up for the task, so let's change this!
 
We allready modified the shock attachment on the first photo, it's attached straight to swingarm behind the motor. So it's not mounted on the motor anymore. I should lengthen the swingarm 30mm from the left side to allow 30mm increase to width of the motor, but that's easy.

We have upgraded Kelly Controller to it and pushed it to 40v 55A instead of stock 24V 23A. But at 2100 watts the effiency of xyd-13 motor is only 55%, so about 1150 watts. Huge improvement still, and we are planning to push Revolt 350 phase amp bursts (Mini Kelly's can burst of that about 10 seconds, which is all we need of mx type driving). Geared to 45kmh it should be pretty much beast and do wheelies when wanted. :D
 
Looks really good crossbreak!
Do you know if all "pro" motors from revolt has the 0,3mm laminates?
Or if this only applies to the newer motors? I saw some early thread about the rv160 pro, where 0,3mm lams were stated.
Not much info on revolts website these days.

Personally I think a completely closed motor with the ability to use ferrofluid would be the best compromise.
This type of motor likely would see use in many offroad applications. In which a sealed system is much more forgiving to setup.
 
I just finished a build with rv120 PRO and my results are not up to specs. Does anyone have really good results from this motor in a completed build? Looking at the motor spreadsheet the data from John in cr shows good performance, which controller was used in this testing?

I ask because i tried both Kelly sine kls-s7230 and adaptto midi. On both controllers the auto- identify does not work, after manual connection it works ok but motor heats up really fast. A couple of bursts WOT up to 70km/h and motor is 150 degrees C and must be cooled. Torque is ok but not great, 6kw of power really should give acceleration.

On 72v and 43 kV my top speed is 70km/h which is a bit low as i ride 10/43 gearing and 26" wheels

The Adaptto controller died after 30 mins of riding, response from Adaptto so far is that in their testing some controllers have been damaged when used with rv120motor.
600 USD controller rated for 8kW has then issues driving this motor at max 6-7 kW. Analysis of the adaptto is not done so i'll post results when i get it but i would not easily recommend this motor until i know what is causing the issues.

I read wheazel switched from RV120 to a leaf motor since he was not satisfied with efficiency (this is from reading his cargobike thread.)
A comment on this would be useful!

My preliminary conclusion from all this is that this motor is tough to drive (since Adaptto confirm this) or is having quality issues that somehow cause the low performance.

I`d appreciate any tips on how to proceed. My hall readout shows a good sequence so that should be OK, other than that i can only guess..

Badly placed halls in between them (not 120 degrees apart)?
The motor has some cogging, could there be a short? I guess it would not be possible to ride it at even 70km/h if that was the case.

Sorry to throw a spanner in your enthusiastic thread, but i am a bit desperate. My whole bike is built around this motor so if i can't get it to work well then a LOT of work has to be scrapped. I'd hate to see the same happen to others.
 
larsb said:
I just finished a build with rv120 PRO and my results are not up to specs. Does anyone have really good results from this motor in a completed build? Looking at the motor spreadsheet the data from John in cr shows good performance, which controller was used in this testing?

I ask because i tried both Kelly sine kls-s7230 and adaptto midi. On both controllers the auto- identify does not work, after manual connection it works ok but motor heats up really fast. A couple of bursts WOT up to 70km/h and motor is 150 degrees C and must be cooled. Torque is ok but not great, 6kw of power really should give acceleration.

On 72v and 43 kV my top speed is 70km/h which is a bit low as i ride 10/43 gearing and 26" wheels

The Adaptto controller died after 30 mins of riding, response from Adaptto so far is that in their testing some controllers have been damaged when used with rv120motor.
600 USD controller rated for 8kW has then issues driving this motor at max 6-7 kW. Analysis of the adaptto is not done so i'll post results when i get it but i would not easily recommend this motor until i know what is causing the issues.

I read wheazel switched from RV120 to a leaf motor since he was not satisfied with efficiency (this is from reading his cargobike thread.)
A comment on this would be useful!

My preliminary conclusion from all this is that this motor is tough to drive (since Adaptto confirm this) or is having quality issues that somehow cause the low performance.

I`d appreciate any tips on how to proceed. My hall readout shows a good sequence so that should be OK, other than that i can only guess..

Badly placed halls in between them (not 120 degrees apart)?
The motor has some cogging, could there be a short? I guess it would not be possible to ride it at even 70km/h if that was the case.

Sorry to throw a spanner in your enthusiastic thread, but i am a bit desperate. My whole bike is built around this motor so if i can't get it to work well then a LOT of work has to be scrapped. I'd hate to see the same happen to others.
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yea that sounds like an issue with tuning, though i'd be checking any shorts to the stator too. My maxe doesn't appear to have any issue at all with a 100pro (gets luke warm at most), but i also spent a bit of time tuning too. before that it did get quite warm, and if your motor is getting that hot its a sign that the controller is dumping way too much power into it for little gain. The adaptto's dont seem to do all that well with lower pole count motors for some reason, i imagine due to them being setup for hubs, which from a controllers perspective are rather different (namely, erpm+inductance).

My view on these things (ie people running high power non hubs with adaptto's and having issues) is that its a firmware issue with the adaptto's. Ive heard a few storys like yours, and they match my early experiences before i spent a lot of time tuning. More than that i find that the resolution available in the tuning isn't fine enough, each step for many settings seems to be too large. Probably fine for hubs but not for smaller motors that often have a higher erpm/lower inductance, and thus greater sensitivity to tuning.
 
@larsb sorry to hear you are struggling to make motor and controller play nice. Hopefully you some input from others that have done Revolt build here as I don't have a clue what you should check for.

However I would think that if all goes south you might still have options that could work for your build. Vito posted something about QSMotors new inrunner in this QSMOTOR thread. I remember I thought that could be an alternative to the Revolt motors, at least size wise. And I think they got a controller lined up to match the new motor. If all ells fails you could possible fit the new QS into your build? Or maybe the BHT motor? Lets hope it does not go so far and cross our fingers for that someone that have already sorted trough the same problems you are having.
 
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