#crossbreaks' midmotor CB120

[crossbreak]

I'm using #35 and the 11t and 50t are showing some decent wear for >1000mi- I just don't see a bmx chain being happy with even 6kw for long.

for such small sprockets a flanged sprocket would be needed to fit. like this kart sprocket:
http://www.magnaracing.com/index.php?main_page=product_info&cPath=30_363_671&products_id=2674&zenid=97c981fc14ec0ca7f4367276e18eb9c9

sadly, they are very expensive. These sprockets have a 15mm bore. As the motor axle is 17mm, this would need some redesign. i did not find a flanged #35. The smallest non flanged #35 would be 15T if i looked right. But 15t for a #35 or a 13T 415h sprocket fits just right into the picture IMO

What y'all think, 6 phase revolt sounds hot or not?

you get 15kW FOC controller for little more than $200 these days. Why bother with 6-phase? http://kellycontroller.com/kls7230s24v-72v300asinusoidal-brushless-motor-controller-p-1343.html
If you manage to install a 110mm wide motor assembly, it should not be a problem to mount the controller if it's even smaller.
The larger the controller, the cheaper it gets per kW. So why throw away money and make things more complicated than they have to be?

Even if that motor has low efficiency as some posted in this thread

that's moaning on a high level. From calcs even the non-pro scratches the 90's. Big Block and BHT are far away from that. Try running a BHT at 3000rpm, it get's quite hot even without any load.
still, better bearings and lamination is what we are after. I think Km² is really sufficient for most ebike needs here...with a simple 4:1 reduction, the rv120 outperforms even the latest Cromotor (Km²= 19.5 N²m²/W) in terms of copper loss. The new Cro is by far the most impressive hubmotor i have seen yet. Still...way to heavy

 

[macribs]

I have no worthy comeback to give you crossbreak, as I have never run a 6 phase motor and know very little about them. Reason I asked was that I have been fascinated by 6 phase motors for two years, but the bulk and weight of 6 phase hub motor has put me off. So when I looked at the specs for Rv120 I thought maybe possible to squeeze a few more kw out of that motor if it was actually 6 phase or is it really 2 x 3 phase in one shell? And thinking of that got me thinking of redundancy and the possibility to have a limp home function if one controller dies. Just unplug the dead one and get home running the 6 phase Rv120 as a 3 phase. And rather then running one big very expensive controller to get max power out of the Rv120 with the risk of frying controller, fet's or caps it seemed appealing to me to use two cheaper controllers preferable small or tiny ones like the phaserunner. My thought was more failsafe, and hopefully more power (kw) or at least more current and more acceleration along with the ease of mind from the redundancy.

Would a 6 phase Rv120 possible also run cooler then a 3 phase Rv120? I vaguely remember reading something about less heat when a BLDC motor run as a 6 phase rather then 3 phase but I can't remember why that is. Maybe someone could weigh in?

Edited:
Found back to some of the reading I did on 6 phase motors, but there was also a forum thread somewhere that debated pros and cons of the 6 phase BLDC. I will look some more and post that as well if I find back to it. At least here are some light reading on the subject. Seems less current will run on each phase and 5 out of 6 phases will be on at the same time, giving more power and torque with less heat run as a 6 phase rather then if run as a standard 3 phase motor. A 3 phase will run 2 out of 3 phases.

http://www.unicopter.com/1931.html

Better bearings and lamination is what we are after

That does not mean we need to stop with better bearings and thinner laminations, if making a custom ES version why not make it a 6 phase with better bearings and thinner lamination? Winding as 6 phase will make motor run cooler and with more power putting less stress on each controller reducing the chance of a meltdown both for motor and controllers as well.


Now a 6 phase motor with more power and torque with less heat then a 3 phase that does sound attractive to me, then there is the happiness of redundancy and putting less stress on each controller. Whats not to like? Heck even the advantage of less stress on each controller alone makes it worth it in my eyes.


If I am far out and wrong about this just let me have it. I am here on ES mainly to learn, so drop a comment if you think I am in the wrong here.

 

[nutnspecial]

The great news is revolt is willing and able to do some custom runs.

Two sets of phases may add benefits of reduncancy and efficiency, but it's whether people think the added cost and other detractions are worth it. If efficiency increase is in the teens, it's not for me.

Are these motors that hard on controllers? I assumed the low kv would have similar erpm as bht/bigblock and play nice with trap or sine of suitable size.

Crossbreak, I'm not sure the extra cost is really what I'm looking for. Are these motors specifically designed with props in mind? I assume there is some efficiency, power, size benefits to outrunners, but the detractions of them really seems to show up on bikes vs planes. If I would use one I'm still thinking 120pro or 160short @ ~125-155mm long, for more of a 8-15kw setup on an offroad bike.

The modded 120 does seem that it would shine compared my current (but now rare-ish) bht @ 5x6" @ 6kw peak. It would be smaller, lighter, and likely at least as capable powerwise without forced cooling. Thing is, I'm not looking to build another bike like that after I use my second bht. Going bigger.

Keep workin on the idea here though, imo there is huge potential to improve upon a decent middirect drive for light bikes, and you've struck on that here.

 

[macribs]

I am still looking for some of the papers I read on 6 phase motors. As they run a 2 x 3 phase motors in one shell one could think it would scale up linear. It does not double up the power but I can't really remember how much. I've got a wage memory of somewhere between 70-80% more power as 6 phase then if motor is run as 3 phase. But I have yet to find back to the source for confirmation on that.

I don't know if this example will be a use case for this much smaller motor, but I think Arlo1 did a dyno test of a 6 phase Zero motor running 82HP on the Dyno.
Seems the 70-80% increase in power holds true for that one at least. https://www.youtube.com/watch?v=3eL0EMFPnVw

If motor is run cooler from winding as 6 phase there should be possible to harvest some serious power out of that relative light weight and nimble Rv120. If we could see peak output close to 20 kw that would be truly amazing. Even if peak power would only be possible for 2-3 seconds. Heck after 2-3 seconds you will be close to top speed anyway

I wonder what would be the added costs of doing 6 phase as well as better laminations and bearings. If not too high difference maybe people will be onboard? I guess what [strike]we all[/strike] most of us are jonsing for is cheapest way of high power in a light weight package with a little touch of durability. Maybe a custom Rv120 could be it?

The only other manufacturer I know who does also 6 phase upon request is Joby motors. But price wise those Joby's are in a hole other league. And then you get the added costs of a one-off motor on top of the steep initial cost of the motor.

 

[crossbreak]

i dont see any efficiency advantages from pseudo 6-phase. A real 6 phase maybe would have a marginal advantage, but then you cannot run it as 3phase anymore, since phase angles are 60° apart, not 120°. There is a reason why 99.9% of all BLDC motors are 3phase. As nutspecial said, that cant be an opition here since this motor is expensive already, i dont see anyone who is willing to pay more for something he wont use anyway.

cheapest way of high power...with a little touch of durability

you can buy that from Revolt already. I see no other motor that does 15kW and only costs $350 and is sub 5kg. That's why i want durable bearings and enclosed stator. These motors are too expensive to throw away after a few hundred miles, since bearings failed or the stator is damaged by dirt ingress. Building things that arent durable are anything but cheap.

 

[crossbreak]

I don't know if this example will be a use case for this much smaller motor, but I think Arlo1 did a dyno test of a 6 phase Zero motor running 82HP on the Dyno.
Seems the 70-80% increase in power holds true for that one at least. https://www.youtube.com/watch?v=3eL0EMFPnVw

You dont need 6phase to run a motor out of spec. These two things have absolutely nothing to do with each other.

 

[macribs]

You dont need 6phase to run a motor out of spec.

Well if that 6 phase lets you run "out of spec" with a cooler running motor I sure would go for that. Cooler running means less chance of failure even with out of spec performance.

If you already have a had communication with Revolt for the group buy, why don't you check the extra price for 6 phase next time you communicate with Revolt? Maybe you can ask what will be the MOQ for a 6 phase version? If you do you can PM me so I don't derail your thread anymore then I already done.

 

[nutnspecial]

I don't think it's a derailment at all. Crossbreak (imo) just thinks it's not worthwile for him and probably most. I'd agree with that, but if there's no complications/major repercussions I'd say go for the asking question part.

Me not having much knowledge or any firsthand exp with these, it's good to know that besides length we are trying to correct a major flaw with these outrunners that applies to our particular application far more than apparent design purpose. That is worth paying extra for.

In general, what really is more desirable for on the ground with dirt and mud- sealed or vented with liquid or air forced cooling?

Ps, a flanged sprocket isn't a very big deal in my exp. Wouldn't be hard to swap another normal sprocket or tack one up from scratch. There's not much torque circularly on that area- just get it fairly true. My ~2500rpm 11t is just tacked 3x to the bht shaft

 

[John in CR]

6 phase the way mine are wound does none of the things Macribs said. The only tangible benefits are:

- higher winding inductance, so for the same Kv the motor is easier for controllers to drive, though the ability to drive low inductance motors varies with controllers. That's because with double the turns on half the teeth you get more mutual inductance on the coils than the summed inductance of half the turns on double the teeth. The higher inductance enables you to push controllers closer to their stated voltage and current limits.

- Smoother quieter starts and operation with common cheap trap controllers, which when added to the fact that very low cost controllers can dependably push 100A or more battery side.

- There's been some speculation that it reduces torque ripple, but while I believe that to be true I don't have sufficient knowledge to make that claim.

Some have split the phases of motors to pump more power into them with 2 controllers, but that was due to controller limitations. I believe Zero offers a split wound motor. These motors remains a 3 phase motor. The strands of each phase are simply terminated in 2 electrically separate bundles at each end.

With the same amount of copper, same steel and magnets, wound to the same Kv, a motor will have the same torque and efficiency. FWIW the first generation motor from the factory I deal with was a 3 phase hubmotor. It was slightly smaller, a 50mm wide 150mm diameter stator, and had peak efficiency of 93%, almost as high as the newer models. It had the same great materials and build quality, and the only reason it's efficiency was slightly lower was due to some extra resistance in the mechanical series/parallel switching mechanism. 6 phase the way mine are wound seems to result in more end-wind copper, but that effect on efficiency must be negligible and likely more than offset by the added cooling of that exposed copper.

 

[alexlk]

I have a Motoped and would like to convert it to electric:
http://imgur.com/a/byJhL

The Motoped was designed to use Honda Type 70 engines:
https://tboltusa.com/store/tech.php?pID=79/Pit+Bike+%26+Honda+50%2F70+Engine+size

Type 50/70 engines are 280mm wide, so I've been reading about many of the bigger more powerful electric motors I've found (Hubmonster, Motenergy1114, Revolt 160 Pro).

I'd be interested in a Rv 160-Pro with a fixed axle and beefed up can with sprocket mounts. I have plenty of room, but slimmer is always better. Would the 160 Pro suffer if the "fan" were replaced by a solid plate for mounting a sprocket?

 

[macribs]

I have a Motoped and would like to convert it to electric:
http://imgur.com/a/byJhL

The Motoped was designed to use Honda Type 70 engines:
https://tboltusa.com/store/tech.php?pID=79/Pit+Bike+%26+Honda+50%2F70+Engine+size

Type 50/70 engines are 280mm wide, so I've been reading about many of the bigger more powerful electric motors I've found (Hubmonster, Motenergy1114, Revolt 160 Pro).

I'd be interested in a Rv 160-Pro with a fixed axle and beefed up can with sprocket mounts. I have plenty of room, but slimmer is always better. Would the 160 Pro suffer if the "fan" were replaced by a solid plate for mounting a sprocket?

Welcome to the forum

 

[crossbreak]

The modded 120 does seem that it would shine compared my current (but now rare-ish) bht @ 5x6" @ 6kw peak. It would be smaller, lighter, and likely at least as capable powerwise without forced cooling.

This motor does outperform the BHT motor easily. With ferrofluid it should be good for around 4kW continuous and 15kW peak. peak power isnt reduced by enclosing it. When i was testing the BHT two years ago, it seemed to be good for around 1.5kW continous at 48V which fits just into the picture. Pushing high peak power is no achievement. I once pushed 8.5kW into a tiny 500W Bafang BPM hub motor (for 3-4seconds) without overheating it :lol: That was fun, but far from being practical

Still, a motor like this based on the RV160pro would not be much longer, but could have even better bearings, as there is almost no space limitation for them. The RV120custom has the 25mm axle...i' like to use a 30mm one but this is not possible as you can see in the attached picture. Still, 25mm is a lot as most hubmotors have 17mm here.

An RV160custom could have a 35mm axle, with lots of space for thickest phase wires and even liquid cooling. for ebike builds i think a motor like the RV160short or pro are much too large. They have so massive no load loss that a good portion of the battery energy is wasted in no load loss when driving like "normal" though

 

[nutnspecial]

If the 120 is 4x the cont power of a bht, then yes I'd say the 160 is unncessesary weight, cost, power, and associated losses.

How would I go about confirming a base cont rating for my bht? If it is 1.5kw cont I am impressed with it.

I just have it at 100a 16s geared for ~30mph now- and although I notice wattage drop back to maybe 4k on a steep hill, it still does anything I ask, fast. If I run really hard for 20min+ in the summer (like constant full draws (starts/stops) on a tight track, never winding it out or getting top speed), it's then time to cool it off. Last summer all that consisted of was to get on the flat and open it up towards max speed with some pedalling.

If a rv120 is like 3-4x more capable that would have to be wild, and very desirable.

 

[crossbreak]

ask boisrondevens. he does 125V 120A. Sounds more like 2-3x the continous power, but yes this must be fun.. so much power in such a lightweight vehicle

 

[nutnspecial]

Isn't that the power he was burning up his 120regs at? I would prob burn my bht up at that too. But alot of it is application, and that's why I was asking how I could try to determine the continuous power of mine. Probably a dyno is the only proper way to do that.

Nevertheless, if the modded 120reg is smaller, lighter, AND more capable, it's kinda really gonna be the best thing for powerful hybrid bikes. But it does seem like devens really thinks the pro is necessary for our application though, maybe mainly because of the integrated cooling?

 

[crossbreak]

he forgot to install a temp probe in the motor. With his settings, it is easy to burn the Pro, too. Simply since he pushes more than continuous power. I never burned a motor this way, even the Bafang survived the 8,5kW without damage. Burning motors a user fault, not a product failure.

You dont need a dyno for finding continous power. all you need is a CA V3 and a temp probe in the motor to get a real world figure.

if the modded 120reg is smaller, lighter, AND more capable

as said before, it is -magnetically and electrically- the same as the RV120 Pro. So it wont be more capable. Just a bit more efficient (no giant skirt bearing) and more robust. I never wanted a modded 120reg

 

[sn0wchyld]

Revolt checked the design and they say that they can produce it as is. They want to know how many to produce. Stack is 45mm with .35mm lamination like the RV120Pro. I hope i can tell you the price soon

Who is in?

im interested too, let me know if the group buy progresses.

 

[nutnspecial]

Thanks crossbreak, I got it. Indefinite time @ wattage without overheat. Perhaps it is only 1.5 kw, though @ 10lbs I'm guessing it's gotta be better. For instance, what does a mxus v3 weigh, and what is it's cont rating? Those hubs also have less natural cooling ability to consider. I'll be doing some temp test and maybe add a thermistor anyway.
__________
Okay, (120-ES) so with the lams of a pro and the better bearing setup, any drawback at all would be the ommission of the pro's integrated fan?

Could the/a fan still be added? Sure it will need forced cooling to fully compete with the pro?

Do these motors 'eat' controllers? /Controller recommend? I was thinking 100v 100a controller from powervelocity.

What would the mount-up 'look like' for the ES version? It is still fastened by the 'face' of motor?

 

[macribs]

he forgot to install a temp probe in the motor. With his settings, it is easy to burn the Pro, too. Simply since he pushes more than continuous power. I never burned a motor this way, even the Bafang survived the 8,5kW without damage. Burning motors a user fault, not a product failure.

You dont need a dyno for finding continous power. all you need is a CA V3 and a temp probe in the motor to get a real world figure.

if the modded 120reg is smaller, lighter, AND more capable

as said before, it is -magnetically and electrically- the same as the RV120 Pro. So it wont be more capable. Just a bit more efficient (no giant skirt bearing) and more robust. I never wanted a modded 120reg

Any idea if the peak power will increase with the ES edition? I notice there is a 5 kw difference in peak performance 120 Rv Vs 120 Rv PRO.
Other then that what I can see from the drawings is that the pro is 2.3 cm wider and 500 gram more weight, so I guess thats why more peak power? Do you think Es version will be exactly same peak as 120 standard version?

Could the/a fan still be added? Sure it will need forced cooling to fully compete with the pro?

Do these motors 'eat' controllers? /Controller recommend? I was thinking 100v 100a controller from powervelocity.

What would the mount-up 'look like' for the ES version? It is still fastened by the 'face' of motor?

Second what Nutspecial said.
This will come without hall sensors and without temp gauge? So only to be run with controller sensorless? Nutspecial, if motor is without hall sensors that controller from powervelocity will not work - that controller only works with motor with hall sensors.


I am trying to understand what will be the difference between this ES version and the PRO version. Pro has hall sensors and can run "any controller"?
Pro has 5 kw more peak 15 kw total vs 120 ES 10 kw - think that is a real world number or a marketing number?
Pro has fan vs ES has no fan?

For those wishing for most peak power what will be the best choice of the two motors? Saving 2 cm in width and 500 gram weight is not too important to me.
I don't know how the lamination of ES version will affect the peak power and losses, but I do realize peak power will only be for few seconds at a time. But oh so fun.

 

[sn0wchyld]

Thanks crossbreak, I got it. Indefinite time @ wattage without overheat. Perhaps it is only 1.5 kw, though @ 10lbs I'm guessing it's gotta be better. For instance, what does a mxus v3 weigh, and what is it's cont rating? Those hubs also have less natural cooling ability to consider. I'll be doing some temp test and maybe add a thermistor anyway.
__________
Okay, (120-ES) so with the lams of a pro and the better bearing setup, any drawback at all would be the ommission of the pro's integrated fan?

Could the/a fan still be added? Sure it will need forced cooling to fully compete with the pro?

Do these motors 'eat' controllers? /Controller recommend? I was thinking 100v 100a controller from powervelocity.

What would the mount-up 'look like' for the ES version? It is still fastened by the 'face' of motor?

to compete with the pro the fan would absolutely be needed. personally i'd vote for open covers, but its easy enough to mod these/make my own if everyone else wants sealed. the other option is to get revolt to make the covers with higher surface area (ie rippled surface inside and out) which would help. the non driven side could be made very open since its not taking any torque.

controller shouldnt be an issue, though i think factory installed temp sensor would be good.

 

[nutnspecial]

I just assumed it would have halls. I could see not having them for a plane or something running a single speed, but don't we want them for our purposes?

Is it the width or price (or both) keeping us from shooting for a modded pro to begin with?
Or is there the opinion that neither/one are worth it?

 

[crossbreak]

Any idea if the peak power will increase with the ES edition?

as said, magnetically it is the same as the RV120pro. So no. It will overheat even faster as cooling will be worse. How much worse? We dont know till we test.

I can see from the drawings is that the pro is 2.3 cm wider and 500 gram more weight, so I guess thats why more peak power?

cant tell much from that. As said, we must test this. For sure, it will overheat faster due more iron loss - worse lamination. Mass has no effect here as it is nowhere close to the stator

This will come without hall sensors and without temp gauge?

this will come with both. 10k thermistor so you can connect it to a CA V3 easily. We are ES. So we use CA V3. Its simple, it's crude, still it's the best thing on earth

trying to understand what will be the difference between this ES version and the PRO version. Pro has hall sensors and can run "any controller"?

as inductance figures are high enough to drive this one easily. i doubt that even the cheapest controllers may have a problem. Anyway, i only had two Xiechang/lyen controllers (worst ones you can buy) that performed so bad that i got rid of them. the cheapo Greentime controllers did better. I had no problems even driving a 80100 with a 12Fet. So: cant tel. but there is really no reason to use a $20 controller on a $400 motor.

Pro has 5 kw more peak 15 kw total vs 120 ES 10 kw - think that is a real world number or a marketing number?
Pro has fan vs ES has no fan?

This "fan" isnt really a fan, as it blows air in no direction from what i can see: My word: TEST. I think that real world figures will be something in between those two.

For those wishing for most peak power what will be the best choice of the two motors?

iron and copper mass are the same, so it wont matter much (or at all)

I don't know how the lamination of ES version will affect the peak power and losses

Thinner lams are better: .35 lams will only have around 50% of the eddy losses of a .5lams stack

Is it the width or price (or both) keeping us from shooting for a modded pro to begin with?
Or is there the opinion that neither/one are worth it?

if you have a different motor with equal specs?

to compete with the pro the fan would absolutely be needed. personally i'd vote for open covers

i second that. enclosing it is a compromise for sure. Still, with Statorade this thing will be more than competitive i believe.

 

[nutnspecial]

Is devans the only one here that has/is running the reg and the pro? Seems the combo of .35 lams and pro ventilator do make quite a difference. Since the pro vent design won't be easily done diy, I'm cautious to end up with something marginally smaller and stronger for same money, that is difficult to keep cool.

I do understand if we want to save money (from what a custom pro would cost) and have the ability to try sealed/statorade though. Possibly sealed/statorade and also forced cooling over the exterior could be a good combo.

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.

 

[crossbreak]

I'm cautious to end up with something marginally smaller and stronger for same money

"marginally"...comparing load ratings of the bearings, this is not marginal: 61802 C0=1.1kN, 6301 (latest design) C0=4.2kN, additionally, the custom design has shorter support distance.
So maybe you end up with something that works for just a few months since it was designed for aircraft and not dirt bikes

Open blades/props aren't good

Cant follow you...that's contradictory. Coming from a BHT that is enclosed and robust with oversized bearings, going to an aircraft motor that is prone to dirt and has weak bearings must be a long road. As said, it's your decision. You have to decide yourself if you're in or not.

 

[sn0wchyld]

Is devans the only one here that has/is running the reg and the pro? Seems the combo of .35 lams and pro ventilator do make quite a difference. Since the pro vent design won't be easily done diy, I'm cautious to end up with something marginally smaller and stronger for same money, that is difficult to keep cool.

I do understand if we want to save money (from what a custom pro would cost) and have the ability to try sealed/statorade though. Possibly sealed/statorade and also forced cooling over the exterior could be a good combo.

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.

honsetly if were going to go for a custom sealed one, might as well do something to increase the surface area. I'd put far more effort/money into that than into some kind of forced air cooling. one of the biggest issues with heat dissipation of sealed motors like this and your average hub is the lack of surface area. just putting some ribs/ridges in the side cover (and ideally the magnet backing ring) could double the surface area, which would make a huge difference to cont. power.